// Category: debezium-using
// Type: assembly
[id="debezium-connector-for-oracle"]
= {prodname} Connector for Oracle

:context: oracle
:data-collection: table
:mbean-name: {context}
:connector-file: {context}
:connector-name: Oracle
ifdef::community[]
:toc:
:toc-placement: macro
:linkattrs:
:icons: font

toc::[]

[[oracle-overview]]
== Overview
endif::community[]

{prodname}'s Oracle connector captures and records row-level changes that occur in databases on an Oracle server,
including tables that are added while the connector is running.
You can configure the connector to emit change events for specific subsets of schemas and tables, or to ignore, mask, or truncate values in specific columns.

ifdef::community[]
For information about the Oracle Database versions that are compatible with this connector, see the link:https://debezium.io/releases/[{prodname} release overview].
endif::community[]
ifdef::product[]
For information about the Oracle Database versions that are compatible with this connector, see the link:{LinkDebeziumSupportedConfigurations}[{NameDebeziumSupportedConfigurations}].
endif::product[]

{prodname} ingests change events from Oracle by using the native LogMiner database package
ifdef::community[]
 or the https://docs.oracle.com/database/121/XSTRM/xstrm_intro.htm#XSTRM72647[XStream API].
While the connector might work with a variety of Oracle versions and editions, only Oracle EE 12 and 19 have been tested.
endif::community[]
ifdef::product[]
.

Information and procedures for using a {prodname} Oracle connector are organized as follows:

  * xref:how-debezium-oracle-connectors-work[]
  * xref:descriptions-of-debezium-oracle-connector-data-change-events[]
  * xref:how-debezium-oracle-connectors-map-data-types[]
  * xref:setting-up-oracle-to-work-with-debezium[]
  * xref:deployment-of-debezium-oracle-connectors[]
  * xref:descriptions-of-debezium-oracle-connector-configuration-properties[]
  * xref:monitoring-debezium-oracle-connector-performance[]
  * xref:how-debezium-oracle-connectors-handle-faults-and-problems[]
endif::product[]

// Type: assembly
// ModuleID: how-debezium-oracle-connectors-work
// Title: How {prodname} Oracle connectors work
[[how-the-oracle-connector-works]]
== How the Oracle connector works

To optimally configure and run a {prodname} Oracle connector, it is helpful to understand how the connector performs snapshots, streams change events, determines Kafka topic names, uses metadata, and implements event buffering.

ifdef::product[]
For more information, see the following topics:

* xref:how-debezium-oracle-connectors-perform-database-snapshots[]
* xref:default-names-of-kafka-topics-that-receive-debezium-oracle-change-event-records[]
* xref:how-debezium-oracle-connectors-expose-database-schema-changes[]
* xref:debezium-oracle-connector-generated-events-that-represent-transaction-boundaries[]
* xref:how-the-debezium-oracle-connector-uses-event-buffering[]

endif::product[]

// Type: concept
// Title: How {prodname} Oracle connectors perform database snapshots
// ModuleID: how-debezium-oracle-connectors-perform-database-snapshots
[[oracle-snapshots]]
=== Snapshots

Typically, the redo logs on an Oracle server are configured to not retain the complete history of the database.
As a result, the {prodname} Oracle connector cannot retrieve the entire history of the database from the logs.
To enable the connector to establish a baseline for the current state of the database, the first time that the connector starts, it performs an initial _consistent snapshot_ of the database.

You can customize the way that the connector creates snapshots by setting the value of the xref:oracle-property-snapshot-mode[`snapshot.mode`] connector configuration property.
By default, the connector's snapshot mode is set to `initial`.

[[default-workflow-for-performing-an-initial-snapshot]]
.Default connector workflow for creating an initial snapshot
When the snapshot mode is set to the default, the connector completes the following tasks to create a snapshot:

1. Determines the tables to be captured.
2. Obtains a `ROW SHARE MODE` lock on each of the captured tables to prevent structural changes from occurring during creation of the snapshot. {prodname} holds the locks for only a short time.
3. Reads the current system change number (SCN) position from the server's redo log.
4. Captures the structure of all relevant tables.
5. Releases the locks obtained in Step 2.
6. Scans all of the relevant database tables and schemas as valid at the SCN position that was read in Step 3 (`SELECT * FROM ... AS OF SCN 123`), generates a `READ` event for each row, and then writes the event records to the table-specific Kafka topic.
7. Records the successful completion of the snapshot in the connector offsets.

After the snapshot process begins, if the process is interrupted due to connector failure, rebalancing, or other reasons, the process restarts after the connector restarts.
After the connector completes the initial snapshot, it continues streaming from the position that it read in Step 3 so that it does not miss any updates.
If the connector stops again for any reason, after it restarts, it resumes streaming changes from where it previously left off.

[id="oracle-connector-snapshot-mode-options"]
.Settings for `snapshot.mode` connector configuration property
[cols="30%a,70%a",options="header"]
|===
|Setting |Description

|`initial`
|The connector performs a database snapshot as described in the xref:default-workflow-for-performing-an-initial-snapshot[default workflow for creating an initial snapshot].
After the snapshot completes, the connector begins to stream event records for subsequent database changes.

|`initial_only`
|The connector performs a database snapshot and stops before streaming any change event records, not allowing any subsequent change events to be captured.

|`schema_only`
|The connector captures the structure of all relevant tables, performing all of the steps described in the xref:default-workflow-for-performing-an-initial-snapshot[default snapshot workflow], except that it does not create `READ` events to represent the data set at the point of the connector's start-up (Step 6).

|`schema_only_recovery`
|Set this option to restore a database schema history topic that is lost or corrupted.
After a restart, the connector runs a snapshot that rebuilds the topic from the source tables.
You can also set the property to periodically prune a database schema history topic that experiences unexpected growth. +
 +
WARNING: Do not use this mode to perform a snapshot if schema changes were committed to the database after the last connector shutdown.
|===

For more information, see xref:oracle-property-snapshot-mode[`snapshot.mode`] in the table of connector configuration properties.

// Type: concept
// ModuleID: debezium-oracle-ad-hoc-snapshots
[id="oracle-ad-hoc-snapshots"]
==== Ad hoc snapshots
include::{partialsdir}/modules/all-connectors/con-connector-ad-hoc-snapshots.adoc[leveloffset=+3]

// Type: concept
[id="oracle-incremental-snapshots"]
==== Incremental snapshots
include::{partialsdir}/modules/all-connectors/con-connector-incremental-snapshot.adoc[leveloffset=+3]

[WARNING]
====
The {prodname} connector for Oracle does not support schema changes while an incremental snapshot is running.
====

// Type: concept
// ModuleID: default-names-of-kafka-topics-that-receive-debezium-oracle-change-event-records
// Title: Default names of Kafka topics that receive {prodname} Oracle change event records
[[oracle-topic-names]]
=== Topic names

By default, the Oracle connector writes change events for all `INSERT`, `UPDATE`, and `DELETE` operations that occur in a table to a single Apache Kafka topic that is specific to that table.
The connector uses the following convention to name change event topics:

_topicPrefix.schemaName.tableName_

The following list provides definitions for the components of the default name:

_topicPrefix_:: The topic prefix as specified by the xref:oracle-property-topic-prefix[`topic.prefix`] connector configuration property.

_schemaName_:: The name of the schema in which the operation occurred.

_tableName_:: The name of the table in which the operation occurred.

For example, if `fulfillment` is the server name, `inventory` is the schema name, and the database contains tables with the names `orders`, `customers`, and `products`,
the {prodname} Oracle connector emits events to the following Kafka topics, one for each table in the database:

----
fulfillment.inventory.orders
fulfillment.inventory.customers
fulfillment.inventory.products
----

The connector applies similar naming conventions to label its internal database schema history topics, xref:oracle-schema-change-topic[schema change topics], and xref:oracle-transaction-metadata[transaction metadata topics].

If the default topic name do not meet your requirements, you can configure custom topic names.
To configure custom topic names, you specify regular expressions in the logical topic routing SMT.
For more information about using the logical topic routing SMT to customize topic naming, see xref:{link-topic-routing}#topic-routing[Topic routing].

// Type: concept
// ModuleID: how-debezium-oracle-connectors-expose-database-schema-changes
// Title: How {prodname} Oracle connectors expose database schema changes
[[oracle-schema-change-topic]]
=== Schema change topic

You can configure a {prodname} Oracle connector to produce schema change events that describe structural changes that are applied to captured tables in the database.
The connector writes schema change events to a Kafka topic named `_<serverName>_`, where `_topicName_` is the namespace that is specified in the xref:oracle-property-topic-prefix[`topic.prefix`] configuration property.

{prodname} emits a new message to this topic whenever it streams data from a new table.

Messages that the connector sends to the schema change topic contain a payload, and, optionally, also contain the schema of the change event message.
The payload of a schema change event message includes the following elements:

`ddl`:: Provides the SQL `CREATE`, `ALTER`, or `DROP` statement that results in the schema change.
`databaseName`:: The name of the database to which the statements are applied.
The value of `databaseName` serves as the message key.
`tableChanges`::  A structured representation of the entire table schema after the schema change.
The `tableChanges` field contains an array that includes entries for each column of the table.
Because the structured representation presents data in JSON or Avro format, consumers can easily read messages without first processing them through a DDL parser.

[IMPORTANT]
====
When the connector is configured to capture a table, it stores the history of the table's schema changes not only in the schema change topic, but also in an internal database schema history topic.
The internal database schema history topic is for connector use only and it is not intended for direct use by consuming applications.
Ensure that applications that require notifications about schema changes consume that information only from the schema change topic.
====

[IMPORTANT]
====
Never partition the database schema history topic.
For the database schema history topic to function correctly, it must maintain a consistent, global order of the event records that the connector emits to it.

To ensure that the topic is not split among partitions, set the partition count for the topic by using one of the following methods:

* If you create the database schema history topic manually, specify a partition count of `1`.
* If you use the Apache Kafka broker to create the database schema history topic automatically, the topic is created, set the value of the link:{link-kafka-docs}/#brokerconfigs_num.partitions[Kafka `num.partitions`] configuration option to `1`.
====

ifdef::community[]
[WARNING]
====
The schema change topic message format is in an incubating state and might change without notice.
====
endif::community[]

ifdef::community[]
{prodname} emits a new message to this topic whenever it streams data from a new table, or when the structure of the table is altered.

[NOTE]
====
Following a change in table structure, you must follow (the xref:{link-oracle-connector}#surrogate-schema-evolution[schema evolution procedure]).
====
endif::community[]

.Example: Message emitted to the Oracle connector schema change topic
The following example shows a typical schema change message in JSON format.
The message contains a logical representation of the table schema.

[source,json,indent=0,subs="+attributes"]
----
{
  "schema": {
  ...
  },
  "payload": {
    "source": {
      "version": "{debezium-version}",
      "connector": "oracle",
      "name": "server1",
      "ts_ms": 1588252618953,
      "snapshot": "true",
      "db": "ORCLPDB1",
      "schema": "DEBEZIUM",
      "table": "CUSTOMERS",
      "txId" : null,
      "scn" : "1513734",
      "commit_scn": "1513754",
      "lcr_position" : null,
      "rs_id": "001234.00012345.0124",
      "ssn": 1,
      "redo_thread": 1,
      "user_name": "user"
    },
    "ts_ms": 1588252618953, // <1>
    "databaseName": "ORCLPDB1", // <2>
    "schemaName": "DEBEZIUM", //
    "ddl": "CREATE TABLE \"DEBEZIUM\".\"CUSTOMERS\" \n   (    \"ID\" NUMBER(9,0) NOT NULL ENABLE, \n    \"FIRST_NAME\" VARCHAR2(255), \n    \"LAST_NAME" VARCHAR2(255), \n    \"EMAIL\" VARCHAR2(255), \n     PRIMARY KEY (\"ID\") ENABLE, \n     SUPPLEMENTAL LOG DATA (ALL) COLUMNS\n   ) SEGMENT CREATION IMMEDIATE \n  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 \n NOCOMPRESS LOGGING\n  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645\n  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1\n  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)\n  TABLESPACE \"USERS\" ", // <3>
    "tableChanges": [ // <4>
      {
        "type": "CREATE", // <5>
        "id": "\"ORCLPDB1\".\"DEBEZIUM\".\"CUSTOMERS\"", // <6>
        "table": { // <7>
          "defaultCharsetName": null,
          "primaryKeyColumnNames": [ // <8>
            "ID"
          ],
          "columns": [ // <9>
            {
              "name": "ID",
              "jdbcType": 2,
              "nativeType": null,
              "typeName": "NUMBER",
              "typeExpression": "NUMBER",
              "charsetName": null,
              "length": 9,
              "scale": 0,
              "position": 1,
              "optional": false,
              "autoIncremented": false,
              "generated": false
            },
            {
              "name": "FIRST_NAME",
              "jdbcType": 12,
              "nativeType": null,
              "typeName": "VARCHAR2",
              "typeExpression": "VARCHAR2",
              "charsetName": null,
              "length": 255,
              "scale": null,
              "position": 2,
              "optional": false,
              "autoIncremented": false,
              "generated": false
            },
            {
              "name": "LAST_NAME",
              "jdbcType": 12,
              "nativeType": null,
              "typeName": "VARCHAR2",
              "typeExpression": "VARCHAR2",
              "charsetName": null,
              "length": 255,
              "scale": null,
              "position": 3,
              "optional": false,
              "autoIncremented": false,
              "generated": false
            },
            {
              "name": "EMAIL",
              "jdbcType": 12,
              "nativeType": null,
              "typeName": "VARCHAR2",
              "typeExpression": "VARCHAR2",
              "charsetName": null,
              "length": 255,
              "scale": null,
              "position": 4,
              "optional": false,
              "autoIncremented": false,
              "generated": false
            }
          ],
          "attributes": [ // <10>
            {
              "customAttribute": "attributeValue"
            }
          ]
        }
      }
    ]
  }
}
----

.Descriptions of fields in messages emitted to the schema change topic
[cols="1,4,5",options="header"]
|===
|Item |Field name |Description

|1
|`ts_ms`
|Optional field that displays the time at which the connector processed the event. The time is based on the system clock in the JVM running the Kafka Connect task.

In the source object, ts_ms indicates the time that the change was made in the database. By comparing the value for payload.source.ts_ms with the value for payload.ts_ms, you can determine the lag between the source database update and Debezium.

|2
|`databaseName` +
`schemaName`
|Identifies the database and the schema that contains the change.

|3
|`ddl`
|This field contains the DDL that is responsible for the schema change.

|4
|`tableChanges`
|An array of one or more items that contain the schema changes generated by a DDL command.

|5
|`type`
a|Describes the kind of change. The `type` can be set to one of the following values:

`CREATE`:: Table created.
`ALTER`:: Table modified.
`DROP`:: Table deleted.

|6
|`id`
|Full identifier of the table that was created, altered, or dropped.
In the case of a table rename, this identifier is a concatenation of `_<old>_,_<new>_` table names.

|7
|`table`
|Represents table metadata after the applied change.

|8
|`primaryKeyColumnNames`
|List of columns that compose the table's primary key.

|9
|`columns`
|Metadata for each column in the changed table.

|10
|`attributes`
|Custom attribute metadata for each table change.

|===

In messages that the connector sends to the schema change topic, the message key is the name of the database that contains the schema change.
In the following example, the `payload` field contains the `databaseName` key:

[source,json,indent=0,subs="+attributes"]
----
{
  "schema": {
    "type": "struct",
    "fields": [
      {
        "type": "string",
        "optional": false,
        "field": "databaseName"
      }
    ],
    "optional": false,
    "name": "io.debezium.connector.oracle.SchemaChangeKey"
  },
  "payload": {
    "databaseName": "ORCLPDB1"
  }
}
----

// Type: assembly
// ModuleID: debezium-oracle-connector-generated-events-that-represent-transaction-boundaries
// Title: {prodname} Oracle connector-generated events that represent transaction boundaries
[[oracle-transaction-metadata]]
=== Transaction Metadata

{prodname} can generate events that represent transaction metadata boundaries and that enrich data change event messages.

[NOTE]
.Limits on when {prodname} receives transaction metadata
====
{prodname} registers and receives metadata only for transactions that occur after you deploy the connector.
Metadata for transactions that occur before you deploy the connector is not available.
====

Database transactions are represented by a statement block that is enclosed between the `BEGIN` and `END` keywords.
{prodname} generates transaction boundary events for the `BEGIN` and `END` delimiters in every transaction.
Transaction boundary events contain the following fields:

`status`:: `BEGIN` or `END`.
`id`:: String representation of the unique transaction identifier.
`ts_ms`:: The time of a transaction boundary event (`BEGIN` or `END` event) at the data source.
If the data source does not provide {prodname} with the event time, then the field instead represents the time at which {prodname} processes the event.
`event_count` (for `END` events):: Total number of events emmitted by the transaction.
`data_collections` (for `END` events):: An array of pairs of `data_collection` and `event_count` elements that indicates the number of events that the connector emits for changes that originate from a data collection.

The following example shows a typical transaction boundary message:

.Example: Oracle connector transaction boundary event

[source,json,indent=0,subs="attributes"]
----
{
  "status": "BEGIN",
  "id": "5.6.641",
  "ts_ms": 1486500577125,
  "event_count": null,
  "data_collections": null
}

{
  "status": "END",
  "id": "5.6.641",
  "ts_ms": 1486500577691,
  "event_count": 2,
  "data_collections": [
    {
      "data_collection": "ORCLPDB1.DEBEZIUM.CUSTOMER",
      "event_count": 1
    },
    {
      "data_collection": "ORCLPDB1.DEBEZIUM.ORDER",
      "event_count": 1
    }
  ]
}
----

Unless overridden via the xref:oracle-property-topic-transaction[`topic.transaction`] option,
the connector emits transaction events to the xref:oracle-property-topic-prefix[`_<topic.prefix>_`]`.transaction` topic.

// Type: concept
// ModuleID: how-the-debezium-oracle-connector-enriches-change-event-messages-with-transaction-metadata
// Title: How the {prodname} Oracle connector enriches change event messages with transaction metadata
==== Change data event enrichment

When transaction metadata is enabled, the data message `Envelope` is enriched with a new `transaction` field.
This field provides information about every event in the form of a composite of fields:

`id`:: String representation of unique transaction identifier.
`total_order`:: The absolute position of the event among all events generated by the transaction.
`data_collection_order`:: The per-data collection position of the event among all events that were emitted by the transaction.

The following example shows a typical transaction event message:

[source,json,indent=0,subs="attributes"]
----
{
  "before": null,
  "after": {
    "pk": "2",
    "aa": "1"
  },
  "source": {
...
  },
  "op": "c",
  "ts_ms": "1580390884335",
  "transaction": {
    "id": "5.6.641",
    "total_order": "1",
    "data_collection_order": "1"
  }
}
----

// Type: concept
// ModuleID: how-the-debezium-oracle-connector-uses-event-buffering
// Title: How the {prodname} Oracle connector uses event buffering
[[oracle-event-buffering]]
=== Event buffering

Oracle writes all changes to the redo logs in the order in which they occur, including changes that are later discarded by a rollback.
As a result, concurrent changes from separate transactions are intertwined.
When the connector first reads the stream of changes, because it cannot immediately determine which changes are committed or rolled back, it temporarily stores the change events in an internal buffer.
After a change is committed, the connector writes the change event from the buffer to Kafka.
The connector drops change events that are discarded by a rollback.

You can configure the buffering mechanism that the connector uses by setting the property xref:oracle-property-log-mining-buffer-type[`log.mining.buffer.type`].

==== Heap
The default buffer type is configured using `memory`.
Under the default `memory` setting, the connector uses the heap memory of the JVM process to allocate and manage buffered event records.
If you use the `memory` buffer setting, be sure that the amount of memory that you allocate to the Java process can accommodate long-running and large transactions in your environment.

ifdef::community[]
[[oracle-event-buffering-infinispan]]
==== Infinispan
The {prodname} Oracle connector can also be configured to use Infinispan as its cache provider, supporting cache stores both locally with embedded mode or remotely on a server cluster.
In order to use Infinispan, the xref:oracle-property-log-mining-buffer-type[`log.mining.buffer.type`] must be configured using either `infinispan_embedded` or `infinispan_remote`.

In order to allow flexibility with Infinispan cache configurations, the connector expects a series of cache configuration properties to be supplied when using Infinispan to buffer event data.
See the xref:oracle-connector-properties[configuration properties] in the `log.mining.buffer.infinispan.cache` namespace.
The contents of these configuration properties depend on whether the connector is to integrate with a remote Infinispan cluster or to use the embedded engine.

For example, the following illustrates what an embedded configuration would look like for the transaction cache property when using Infinispan in embedded mode:

[source,xml]
----
<local-cache name="transactions">
  <persistence passivation="false">
    <file-store fetch-state="true" read-only="false" preload="true" shared="false" segmented="false" path="./data" />
  </persistence>
</local-cache>
----

Looking at the configuration in-depth, the cache is configured to be persistent.
All caches should be configured this way to avoid loss of transaction events across connector restarts if a transaction is in-progress.
Additionally, the location where the cache is kept is defined by the `path` attribute and this should be a shared location accessible all possible runtime environments.

[NOTE]
====
When supplying XML configuration as a JSON connector property value, line breaks must be omitted or replaced with a `\n` character.
====

Another example, the following illustrates the same cache configured with an Infinispan cluster:

[source,xml]
----
<distributed-cache name="transactions" statistics="true">
  <encoding media-type="application/x-protostream" />
  <persistence passivation="false">
    <file-store fetch-state="true" read-only="false" preload="true" shared="false" segmented="false" />
  </persistence>
</distributed-cache>
----

Just like the embedded local-cache configuration from the previous example, this configuration is also defined to be persistent.
All caches should be configured this way to avoid loss of transaction events across connector restarts if a transaction is in-progress.

However, there are a few differences with noting.
First, the cache is defined as a distributed cache rather than a local-cache.
Secondly, the cache is defined to use the `application/x-protostream` encoding, which is required for all Debezium caches.
And lastly, no `path` attribute is necessary on the file store definition since the Infinispan cluster will handle this automatically.

[IMPORTANT]
====
The Infinispan buffer type is considered incubating; the cache formats may change between versions and may require a re-snapshot.
The migration notes will indicate whether this is needed.

Additionally, when removing a {prodname} Oracle connector that uses the Infinispan buffer, the persisted cache files are not removed from disk automatically.
If the same buffer location will be used by a new connector deployment, the files should be removed manually before deploying the new connector.
====

===== Infinispan Hotrod client integration

The {prodname} Oracle connector utilizes the Hotrod client to communicate with the Infinispan cluster.
Any connector property that is prefixed with `log.mining.buffer.infinispan.client.` will be passed directly to the Hotrod client using the `infinispan.client.` namespace, allowing for complete customization of how the client is to interact with the cluster.

There is at least one required configuration property that must be supplied when using this Infinspan mode:

`log.mining.buffer.infinispan.client.hotrod.server_list`::
Specifies the list of Infinispan server hostname and port combinations, using `<hostname>:<port>` format.
endif::community[]

// Type: concept
// ModuleID: debezium-oracle-connector-scn-gap-detection
// Title: How the {prodname} Oracle connector detects gaps in SCN values
[[scn-jumps]]
=== SCN gap detection

When the {prodname} Oracle connector is configured to use LogMiner, it collects change events from Oracle by using a start and end range that is based on system change numbers (SCNs).
The connector manages this range automatically, increasing or decreasing the range depending on whether the connector is able to stream changes in near real-time, or must process a backlog of changes due to the volume of large or bulk transactions in the database.

Under certain circumstances, the Oracle database advances the SCN by an unusually high amount, rather than increasing the SCN value at a constant rate.
Such a jump in the SCN value can occur because of the way that a particular integration interacts with the database, or as a result of events such as hot backups.

The {prodname} Oracle connector relies on the following configuration properties to detect the SCN gap and adjust the mining range.

`log.mining.scn.gap.detection.gap.size.min`:: Specifies the minimum gap size.
`log.mining.scn.gap.detection.time.interval.max.ms`:: Specifies the maximum time interval.

The connector first compares the difference in the number of changes between the current SCN and the highest SCN in the current mining range.
If the difference between the current SCN value and the highest SCN value is greater than the minimum gap size, then the connector has potentially detected a SCN gap.
To confirm whether a gap exists, the connector next compares the timestamps of the current SCN and the SCN at the end of the previous mining range.
If the difference between the timestamps is less than the maximum time interval, then the existence of an SCN gap is confirmed.

When an SCN gap occurs, the {prodname} connector automatically uses the current SCN as the end point for the range of the current mining session.
This allows the connector to quickly catch up to the real-time events without mining smaller ranges in between that return no changes because the SCN value was increased by an unexpectedly large number.
When the connector performs the preceding steps in response to an SCN gap, it ignores the value that is specified by the xref:oracle-property-log-mining-batch-size-max[log.mining.batch.size.max] property.
After the connector finishes the mining session and catches back up to real-time events, it resumes enforcement of the maximum log mining batch size.

[WARNING]
====
SCN gap detection is available only if the large SCN increment occurs while the connector is running and processing near real-time events.
====

// Type: concept
// ModuleID: how-debezium-manages-offsets-in-databases-that-change-infrequently
// Title: How {prodname} manages offsets in databases that change infrequently
[[low-change-frequency-offset-management]]
=== Low change frequency offset management

The {prodname} Oracle connector tracks system change numbers in the connector offsets so that when the connector is restarted, it can begin where it left off.
These offsets are part of each emitted change event; however, when the frequency of database changes are low (every few hours or days), the offsets can become stale and prevent the connector from successfully restarting if the system change number is no longer available in the transaction logs.

For connectors that use non-CDB mode to connect to Oracle, you can enable xref:oracle-property-heartbeat-interval-ms[`heartbeat.interval.ms`] to force the connector to emit a heartbeat event at regular intervals so that offsets remain synchronized.

For connectors that use CDB mode to connect to Oracle, maintaining synchronization is more complicated.
Not only must you set xref:oracle-property-heartbeat-interval-ms[`heartbeat.interval.ms`], but it's also necessary to set xref:oracle-property-heartbeat-action-query[`heartbeat.action.query`].
Specifying both properties is required, because in CDB mode, the connector specifically tracks changes inside the PDB only.
A supplementary mechanism is needed to trigger change events from within the pluggable database.
At regular intervals, the heartbeat action query causes the connector to insert a new table row, or update an existing row in the pluggable database.
{prodname} detects the table changes and emits change events for them, ensuring that offsets remain synchronized, even in pluggable databases that process changes infrequently.

[NOTE]
====
For the connector to use the `heartbeat.action.query` with tables that are not owned by the xref:creating-users-for-the-connector[connector user account], you must grant the connector user permission to run the necessary `INSERT` or `UPDATE` queries on those tables.
====

// Type: assembly
// ModuleID: descriptions-of-debezium-oracle-connector-data-change-events
// Title: Descriptions of {prodname} Oracle connector data change events
[[oracle-events]]
== Data change events

Every data change event that the Oracle connector emits has a key and a value.
The structures of the key and value depend on the table from which the change events originate.
For information about how {prodname} constructs topic names, see xref:oracle-topic-names[Topic names].

[WARNING]
====
The {prodname} Oracle connector ensures that all Kafka Connect _schema names_ are http://avro.apache.org/docs/current/spec.html#names[valid Avro schema names].
This means that the logical server name must start with alphabetic characters or an underscore ([a-z,A-Z,\_]),
and the remaining characters in the logical server name and all characters in the schema and table names must be alphanumeric characters or an underscore ([a-z,A-Z,0-9,\_]).
The connector automatically replaces invalid characters with an underscore character.

Unexpected naming conflicts can result when the only distinguishing characters between multiple logical server names, schema names, or table names are not valid characters, and those characters are replaced with underscores.
====

{prodname} and Kafka Connect are designed around _continuous streams of event messages_.
However, the structure of these events might change over time, which can be difficult for topic consumers to handle.
To facilitate the processing of mutable event structures, each event in Kafka Connect is self-contained.
Every message key and value has two parts: a _schema_ and _payload_.
The schema describes the structure of the payload, while the payload contains the actual data.

[WARNING]
====
Changes that are performed by the `SYS` or `SYSTEM` user accounts are not captured by the connector.
====
ifdef::product[]
The following topics contain more details about data change events:

* xref:about-keys-in-debezium-oracle-connector-change-events[]
* xref:about-values-in-debezium-oracle-connector-change-events[]
endif::product[]

// Type: concept
// ModuleID: about-keys-in-debezium-oracle-connector-change-events
// Title: About keys in {prodname} Oracle connector change events
[[oracle-change-event-keys]]
=== Change event keys

For each changed table, the change event key is structured such that a field exists for each column in the primary key (or unique key constraint) of the table at the time when the event is created.

For example, a `customers` table that is defined in the `inventory` database schema, might have the following change event key:

[source,sql,indent=0]
----
CREATE TABLE customers (
  id NUMBER(9) GENERATED BY DEFAULT ON NULL AS IDENTITY (START WITH 1001) NOT NULL PRIMARY KEY,
  first_name VARCHAR2(255) NOT NULL,
  last_name VARCHAR2(255) NOT NULL,
  email VARCHAR2(255) NOT NULL UNIQUE
);
----

If the value of the xref:oracle-property-topic-prefix[`_<topic.prefix>_`]`.transaction` configuration property is set to `server1`,
the JSON representation for every change event that occurs in the `customers` table in the database features the following key structure:

[source,json,indent=0,sub="attributes"]
----
{
    "schema": {
        "type": "struct",
        "fields": [
            {
                "type": "int32",
                "optional": false,
                "field": "ID"
            }
        ],
        "optional": false,
        "name": "server1.INVENTORY.CUSTOMERS.Key"
    },
    "payload": {
        "ID": 1004
    }
}
----

The `schema` portion of the key contains a Kafka Connect schema that describes the content of the key portion.
In the preceding example, the `payload` value is not optional, the structure is defined by a schema named `server1.DEBEZIUM.CUSTOMERS.Key`, and there is one required field named `id` of type `int32`.
The value of the key's `payload` field indicates that it is indeed a structure (which in JSON is just an object) with a single `id` field, whose value is `1004`.

Therefore, you can interpret this key as describing the row in the `inventory.customers` table (output from the connector named `server1`) whose `id` primary key column had a value of `1004`.

////
[NOTE]
====
Although the `column.exclude.list` configuration property allows you to remove columns from the event values, all columns in a primary or unique key are always included in the event's key.
====

[WARNING]
====
If the table does not have a primary or unique key, then the change event's key is null. This makes sense since the rows in a table without a primary or unique key constraint cannot be uniquely identified.
====
////

// Type: concept
// ModuleID: about-values-in-debezium-oracle-connector-change-events
// Title: About values in {prodname} Oracle connector change events
[[oracle-change-event-values]]
=== Change event values

The structure of a value in a change event message mirrors the structure of the xref:oracle-change-event-keys[message key in the change event] in the message, and contains both a _schema_ section and a _payload_ section.

.Payload of a change event value
An _envelope_ structure in the payload sections of a change event value contains the following fields:

`op`:: A mandatory field that contains a string value describing the type of operation.
The `op` field in the payload of an Oracle connector change event value contains one of the following values: `c` (create or insert), `u` (update), `d` (delete), or `r` (read, which indicates a snapshot).
`before`:: An optional field that, if present, describes the state of the row _before_ the event occurred.
The structure is described by the `server1.INVENTORY.CUSTOMERS.Value` Kafka Connect schema, which the `server1` connector uses for all rows in the `inventory.customers` table.

// [WARNING]
// ====
// Whether or not this field and its elements are available is highly dependent on the https://docs.oracle.com/database/121/SUTIL/GUID-D2DDD67C-E1CC-45A6-A2A7-198E4C142FA3.htm#SUTIL1583[Supplemental Logging] configuration applying to the table.
// ====

`after`:: An optional field that, if present, contains the state of a row _after_ a change occurs.
The structure is described by the same `server1.INVENTORY.CUSTOMERS.Value` Kafka Connect schema that is used for the `before` field.
`source`:: A mandatory field that contains a structure that describes the source metadata for the event.
In the case of the Oracle connector, the structure includes the following fields:
+
* The {prodname} version.
* The connector name.
* Whether the event is part of an ongoing snapshot or not.
* The transaction id (not includes for snapshots).
* The SCN of the change.
* A timestamp that indicates when the record in the source database changed (for snapshots, the timestamp indicates when the snapshot occurred).
* Username who made the change
+
[TIP]
====
The `commit_scn` field is optional and describes the SCN of the transaction commit that the change event participates within.
ifdef::community[]
This field is only present when using the LogMiner connection adapter.
endif::community[]
====
ifdef::community[]
+
[TIP]
====
The `user_name` field is only populated when using the LogMiner connection adapter.
====
endif::community[]

`ts_ms`:: An optional field that, if present, contains the time (based on the system clock in the JVM that runs the Kafka Connect task) at which the connector processed the event.

.Schema of a change event value
The _schema_ portion of the event message's value contains a schema that describes the envelope structure of the payload and the nested fields within it.

ifdef::product[]
For more information about change event values, see the following topics:

* xref:oracle-create-events[_create_ events]
* xref:oracle-update-events[_update_ events]
* xref:oracle-delete-events[_delete_ events]
* xref:oracle-truncate-events[_truncate_ events]
endif::product[]


// Type: continue
[[oracle-create-events]]
=== _create_ events

The following example shows the value of a _create_ event value from the `customers` table that is described in the xref:oracle-change-event-keys[change event keys] example:

[source,json,indent=0,subs="+attributes"]
----
{
    "schema": {
        "type": "struct",
        "fields": [
            {
                "type": "struct",
                "fields": [
                    {
                        "type": "int32",
                        "optional": false,
                        "field": "ID"
                    },
                    {
                        "type": "string",
                        "optional": false,
                        "field": "FIRST_NAME"
                    },
                    {
                        "type": "string",
                        "optional": false,
                        "field": "LAST_NAME"
                    },
                    {
                        "type": "string",
                        "optional": false,
                        "field": "EMAIL"
                    }
                ],
                "optional": true,
                "name": "server1.DEBEZIUM.CUSTOMERS.Value",
                "field": "before"
            },
            {
                "type": "struct",
                "fields": [
                    {
                        "type": "int32",
                        "optional": false,
                        "field": "ID"
                    },
                    {
                        "type": "string",
                        "optional": false,
                        "field": "FIRST_NAME"
                    },
                    {
                        "type": "string",
                        "optional": false,
                        "field": "LAST_NAME"
                    },
                    {
                        "type": "string",
                        "optional": false,
                        "field": "EMAIL"
                    }
                ],
                "optional": true,
                "name": "server1.DEBEZIUM.CUSTOMERS.Value",
                "field": "after"
            },
            {
                "type": "struct",
                "fields": [
                    {
                        "type": "string",
                        "optional": true,
                        "field": "version"
                    },
                    {
                        "type": "string",
                        "optional": false,
                        "field": "name"
                    },
                    {
                        "type": "int64",
                        "optional": true,
                        "field": "ts_ms"
                    },
                    {
                        "type": "string",
                        "optional": true,
                        "field": "txId"
                    },
                    {
                        "type": "string",
                        "optional": true,
                        "field": "scn"
                    },
                    {
                        "type": "string",
                        "optional": true,
                        "field": "commit_scn"
                    },
                    {
                        "type": "string",
                        "optional": true,
                        "field": "rs_id"
                    },
                    {
                        "type": "int32",
                        "optional": true,
                        "field": "ssn"
                    },
                    {
                        "type": "int32",
                        "optional": true,
                        "field": "redo_thread"
                    },
                    {
                        "type": "string",
                        "optional": true,
                        "field": "user_name"
                    },
                    {
                        "type": "boolean",
                        "optional": true,
                        "field": "snapshot"
                    }
                ],
                "optional": false,
                "name": "io.debezium.connector.oracle.Source",
                "field": "source"
            },
            {
                "type": "string",
                "optional": false,
                "field": "op"
            },
            {
                "type": "int64",
                "optional": true,
                "field": "ts_ms"
            }
        ],
        "optional": false,
        "name": "server1.DEBEZIUM.CUSTOMERS.Envelope"
    },
    "payload": {
        "before": null,
        "after": {
            "ID": 1004,
            "FIRST_NAME": "Anne",
            "LAST_NAME": "Kretchmar",
            "EMAIL": "annek@noanswer.org"
        },
        "source": {
            "version": "{debezium-version}",
            "name": "server1",
            "ts_ms": 1520085154000,
            "txId": "6.28.807",
            "scn": "2122185",
            "commit_scn": "2122185",
            "rs_id": "001234.00012345.0124",
            "ssn": 1,
            "redo_thread": 1,
            "user_name": "user",
            "snapshot": false
        },
        "op": "c",
        "ts_ms": 1532592105975
    }
}
----

In the preceding example, notice how the event defines the following schema:

* The _envelope_ (`server1.DEBEZIUM.CUSTOMERS.Envelope`).
* The `source` structure (`io.debezium.connector.oracle.Source`, which is specific to the Oracle connector and reused across all events).
* The table-specific schemas for the `before` and `after` fields.

[TIP]
====
The names of the schemas for the `before` and `after` fields are of the form `_<logicalName>_._<schemaName>_._<tableName>_.Value`, and thus are entirely independent from the schemas for all other tables.
As a result, when you use the xref:{link-avro-serialization}#avro-serialization[Avro converter], the Avro schemas for tables in each logical source have their own evolution and history.
====

The `payload` portion of this event's _value_, provides information about the event.
It describes that a row was created (`op=c`), and shows that the `after` field value contains the values that were inserted into the `ID`, `FIRST_NAME`, `LAST_NAME`, and `EMAIL` columns of the row.

[TIP]
====
By default, the JSON representations of events are much larger than the rows that they describe.
The larger size is due to the JSON representation including both the schema and payload portions of a message.
You can use the xref:{link-avro-serialization}#avro-serialization[Avro Converter] to decrease the size of messages that the connector writes to Kafka topics.
====

// Type: continue
[[oracle-update-events]]
=== _update_ events

The following example shows an _update_ change event that the connector captures from the same table as the preceding _create_ event.

[source,json,indent=0,subs="+attributes"]
----
{
    "schema": { ... },
    "payload": {
        "before": {
            "ID": 1004,
            "FIRST_NAME": "Anne",
            "LAST_NAME": "Kretchmar",
            "EMAIL": "annek@noanswer.org"
        },
        "after": {
            "ID": 1004,
            "FIRST_NAME": "Anne",
            "LAST_NAME": "Kretchmar",
            "EMAIL": "anne@example.com"
        },
        "source": {
            "version": "{debezium-version}",
            "name": "server1",
            "ts_ms": 1520085811000,
            "txId": "6.9.809",
            "scn": "2125544",
            "commit_scn": "2125544",
            "rs_id": "001234.00012345.0124",
            "ssn": 1,
            "redo_thread": 1,
            "user_name": "user",
            "snapshot": false
        },
        "op": "u",
        "ts_ms": 1532592713485
    }
}
----

The payload has the same structure as the payload of a _create_ (insert) event, but the following values are different:

* The value of the `op` field is `u`, signifying that this row changed because of an update.
* The `before` field shows the former state of the row with the values that were present before the `update` database commit.
* The `after` field shows the updated state of the row, with the `EMAIL` value now set to `anne@example.com`.
* The structure of the `source` field includes the same fields as before, but the values are different, because the connector captured the event from a different position in the redo log.
* The `ts_ms` field shows the timestamp that indicates when {prodname} processed the event.

The `payload` section reveals several other useful pieces of information.
For example, by comparing the `before` and `after` structures, we can determine how a row changed as the result of a commit.
The `source` structure provides information about Oracle's record of this change, providing traceability.
It also gives us insight into when this event occurred in relation to other events in this topic and in other topics.
Did it occur before, after, or as part of the same commit as another event?

[NOTE]
====
When the columns for a row's primary/unique key are updated, the value of the row's key changes.
As a result, {prodname} emits _three_ events after such an update:

* A `DELETE` event.
* A xref:{link-oracle-connector}#oracle-tombstone-events[tombstone event] with the old key for the row.
* An `INSERT` event that provides the new key for the row.
====

// Type: continue
[[oracle-delete-events]]
=== _delete_ events

The following example shows a _delete_ event for the table that is shown in the preceding _create_ and _update_ event examples.
The `schema` portion of the _delete_ event is identical to the `schema` portion for those events.

[source,json,indent=0,subs="+attributes"]
----
{
    "schema": { ... },
    "payload": {
        "before": {
            "ID": 1004,
            "FIRST_NAME": "Anne",
            "LAST_NAME": "Kretchmar",
            "EMAIL": "anne@example.com"
        },
        "after": null,
        "source": {
            "version": "{debezium-version}",
            "name": "server1",
            "ts_ms": 1520085153000,
            "txId": "6.28.807",
            "scn": "2122184",
            "commit_scn": "2122184",
            "rs_id": "001234.00012345.0124",
            "ssn": 1,
            "redo_thread": 1,
            "user_name": "user",
            "snapshot": false
        },
        "op": "d",
        "ts_ms": 1532592105960
    }
}
----

The `payload` portion of the event reveals several differences when compared to the payload of a _create_ or _update_ event:

* The value of the `op` field is `d`, signifying that the row was deleted.
* The `before` field shows the former state of the row that was deleted with the database commit.
* The value of the `after` field is `null`, signifying that the row no longer exists.
* The structure of the `source` field includes many of the keys that exist in _create_ or _update_ events, but the values in the `ts_ms`, `scn`, and `txId` fields are different.
* The `ts_ms` shows a timestamp that indicates when {prodname} processed this event.

The _delete_ event provides consumers with the information that they require to process the removal of this row.

The Oracle connector's events are designed to work with https://cwiki.apache.org/confluence/display/KAFKA/Log+Compaction[Kafka log compaction],
which allows for the removal of some older messages as long as at least the most recent message for every key is kept.
This allows Kafka to reclaim storage space while ensuring the topic contains a complete dataset and can be used for reloading key-based state.

[[oracle-tombstone-events]]
When a row is deleted, the _delete_ event value shown in the preceding example still works with log compaction, because Kafka is able to remove all earlier messages that use the same key.
The message value must be set to `null` to instruct Kafka to remove _all messages_ that share the same key.
To make this possible, by default, {prodname}'s Oracle connector always follows a _delete_ event with a special _tombstone_ event that has the same key but `null` value.
You can change the default behavior by setting the connector property xref:oracle-property-tombstones-on-delete[`tombstones.on.delete`].

// Type: continue
[[oracle-truncate-events]]
=== _truncate_ events

A  _truncate_ change event signals that a table has been truncated.
The message key is `null` in this case, the message value looks like this:

[source,json,indent=0,subs="+attributes"]
----
{
    "schema": { ... },
    "payload": {
        "before": null,
        "after": null,
        "source": { // <1>
            "version": "{debezium-version}",
            "connector": "oracle",
            "name": "oracle_server",
            "ts_ms": 1638974535000,
            "snapshot": "false",
            "db": "ORCLPDB1",
            "sequence": null,
            "schema": "DEBEZIUM",
            "table": "TEST_TABLE",
            "txId": "02000a0037030000",
            "scn": "13234397",
            "commit_scn": "13271102",
            "lcr_position": null,
            "rs_id": "001234.00012345.0124",
            "ssn": 1,
            "redo_thread": 1,
            "user_name": "user"
        },
        "op": "t", // <2>
        "ts_ms": 1638974558961, // <3>
        "transaction": null
    }
}
----

.Descriptions of _truncate_ event value fields
[cols="1,2,7",options="header"]
|===
|Item |Field name |Description

|1
|`source`
a|Mandatory field that describes the source metadata for the event. In a _truncate_ event value, the `source` field structure is the same as for _create_, _update_, and _delete_ events for the same table, provides this metadata:

* {prodname} version
* Connector type and name
* Database and table that contains the new row
* Schema name
* If the event was part of a snapshot (always `false` for _truncate_ events)
* ID of the transaction in which the operation was performed
* SCN of the operation
* Timestamp for when the change was made in the database
* Username who performed the change

|2
|`op`
a|Mandatory string that describes the type of operation. The `op` field value is `t`, signifying that this table was truncated.

|3
|`ts_ms`
a|Optional field that displays the time at which the connector processed the event. The time is based on the system clock in the JVM running the Kafka Connect task. +

In the `source` object, `ts_ms` indicates the time that the change was made in the database. By comparing the value for `payload.source.ts_ms` with the value for `payload.ts_ms`, you can determine the lag between the source database update and {prodname}.

|===

Because _truncate_ events represent changes made to an entire table, and have no message key, in topics with multiple partitions, there is no guarantee that consumers receive _truncate_ events and change events (_create_, _update_, etc.) for to a table in order.
For example, when a consumer reads events from different partitions, it might receive an _update_ event for a table after it receives a _truncate_ event for the same table.
Ordering can be guaranteed only if a topic uses a single partition.

If you do not want to capture _truncate_ events, use the xref:oracle-property-skipped-operations[`skipped.operations`] option to filter them out.

// Type: reference
// ModuleID: how-debezium-oracle-connectors-map-data-types
// Title: How {prodname} Oracle connectors map data types
[[oracle-data-type-mappings]]
== Data type mappings

When the {prodname} {connector-name} connector detects a change in the value of a table row, it emits a change event that represents the change.
Each change event record is structured in the same way as the original table, with the event record containing a field for each column value.
The data type of a table column determines how the connector represents the column's values in change event fields, as shown in the tables in the following sections.

For each column in a table, {prodname} maps the source data type to a _literal type_ and, and in some cases, a _semantic type_, in the corresponding event field.

Literal types:: Describe how the value is literally represented, using one of the following Kafka Connect schema types: `INT8`, `INT16`, `INT32`, `INT64`, `FLOAT32`, `FLOAT64`, `BOOLEAN`, `STRING`, `BYTES`, `ARRAY`, `MAP`, and `STRUCT`.

Semantic types:: Describe how the Kafka Connect schema captures the _meaning_ of the field, by using the name of the Kafka Connect schema for the field.

If the default data type conversions do not meet your needs, you can {link-prefix}:{link-custom-converters}#custom-converters[create a custom converter] for the connector.

For some Oracle large object (CLOB, NCLOB, and BLOB) and numeric data types, you can manipulate the way that the connector performs the type mapping by changing default configuration property settings.
For more information about how {prodname} properties control mappings for these data types, see xref:oracle-binary-character-lob-types[Binary and Character LOB types] and xref:oracle-numeric-types[Numeric types].

ifdef::product[]
For more information about how the {prodname} connector maps Oracle data types, see the following topics:

* xref:oracle-character-types[]
* xref:oracle-binary-character-lob-types[]
* xref:oracle-numeric-types[]
* xref:oracle-boolean-types[]
* xref:oracle-temporal-types[]
* xref:oracle-rowid-types[]
* xref:oracle-user-defined-types[]
* xref:oracle-supplied-types[]
* xref:oracle-default-values[]

endif::product[]

ifdef::community[]
Support for further data types is planned for subsequent releases.
Please file a {jira-url}/browse/DBZ[JIRA issue] for any specific types that might be missing.
endif::community[]

[id="oracle-character-types"]
=== Character types

The following table describes how the connector maps basic character types.

.Mappings for Oracle basic character types
[cols="20%a,15%a,55%a",options="header"]
|===
|Oracle Data Type
|Literal type (schema type)
|Semantic type (schema name) and Notes

|`CHAR[(M)]`
|`STRING`
|n/a

|`NCHAR[(M)]`
|`STRING`
|n/a

|`NVARCHAR2[(M)]`
|`STRING`
|n/a

|`VARCHAR[(M)]`
|`STRING`
|n/a

|`VARCHAR2[(M)]`
|`STRING`
|n/a

|===

[id="oracle-binary-character-lob-types"]
=== Binary and Character LOB types
ifdef::community[]
[NOTE]
====
Support for `BLOB`, `CLOB`, and `NCLOB` is currently in incubating state, that is, the exact semantics, configuration options and so forth might change in future revisions, based on feedback we receive.
Please let us know if you encounter any problems while using these data types.
====
endif::community[]
ifdef::product[]
[IMPORTANT]
====
Use of the `BLOB`, `CLOB`, and `NCLOB` with the {prodname} Oracle connector is a Technology Preview feature only.
Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete.
Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see link:https://access.redhat.com/support/offerings/techpreview[https://access.redhat.com/support/offerings/techpreview].
====
endif::product[]
The following table describes how the connector maps binary and character large object (LOB) data types.

.Mappings for Oracle binary and character LOB types
[cols="20%a,15%a,55%a",options="header"]
|===
|Oracle Data Type
|Literal type (schema type)
|Semantic type (schema name) and Notes

|`BFILE`
|n/a
|_This data type is not supported_

|`BLOB`
|`BYTES`
|Either the raw bytes (the default), a base64-encoded String, or a base64-url-safe-encoded String, or a hex-encoded String, based on the xref:oracle-property-binary-handling-mode[`binary.handling.mode`] connector configuration property setting.

|`CLOB`
|`STRING`
|n/a

|`LONG`
|n/a
|_This data type is not supported._

|`LONG RAW`
|n/a
|_This data type is not supported._

|`NCLOB`
|`STRING`
|n/a

|`RAW`
|n/a
|_This data type is not supported._

|===

[NOTE]
====
Oracle only supplies column values for `CLOB`, `NCLOB`, and `BLOB` data types if they're explicitly set or changed in a SQL statement.
As a result, change events never contain the value of an unchanged `CLOB`, `NCLOB`, or `BLOB` column.
Instead, they contain placeholders as defined by the connector property, `unavailable.value.placeholder`.

If the value of a `CLOB`, `NCLOB`, or `BLOB` column is updated, the new value is placed in the `after` element of the corresponding update change event.
The `before` element contains the unavailable value placeholder.
====

[id="oracle-numeric-types"]
=== Numeric types

The following table describes how the {prodname} Oracle connector maps numeric types.

[NOTE]
====
You can modify the way that the connector maps the Oracle `DECIMAL`, `NUMBER`, `NUMERIC`, and `REAL` data types by changing the value of the connector's xref:oracle-property-decimal-handling-mode[`decimal.handling.mode`] configuration property.
When the property is set to its default value of `precise`, the connector maps these Oracle data types to the Kafka Connect `org.apache.kafka.connect.data.Decimal` logical type, as indicated in the table.
When the value of the property is set to `double` or `string`, the connector uses alternate mappings for some Oracle data types.
For more information, see the _Semantic type and Notes_ column in the following table.
====
.Mappings for Oracle numeric data types
[cols="20%a,15%a,55%a",options="header"]
|===
|Oracle Data Type
|Literal type (schema type)
|Semantic type (schema name) and Notes

|`BINARY_FLOAT`
|`FLOAT32`
|n/a

|`BINARY_DOUBLE`
|`FLOAT64`
|n/a

|`DECIMAL[(P, S)]`
|`BYTES` / `INT8` / `INT16` / `INT32` / `INT64`
|`org.apache.kafka.connect.data.Decimal` if using `BYTES` +
 +
Handled equivalently to `NUMBER` (note that S defaults to 0 for `DECIMAL`).

When the `decimal.handling.mode` property is set to `double`, the connector represents `DECIMAL` values as Java `double` values with schema type `FLOAT64`.

When the `decimal.handling.mode` property is set to `string`, the connector represents DECIMAL values as their formatted string representation with schema type `STRING`.

|`DOUBLE PRECISION`
|`STRUCT`
|`io.debezium.data.VariableScaleDecimal` +
 +
Contains a structure with two fields: `scale` of type `INT32` that contains the scale of the transferred value and `value` of type `BYTES` containing the original value in an unscaled form.

|`FLOAT[(P)]`
|`STRUCT`
|`io.debezium.data.VariableScaleDecimal` +
 +
Contains a structure with two fields: `scale` of type `INT32` that contains the scale of the transferred value and `value` of type `BYTES` containing the original value in an unscaled form.

|`INTEGER`, `INT`
|`BYTES`
|`org.apache.kafka.connect.data.Decimal` +
 +
`INTEGER` is mapped in Oracle to NUMBER(38,0) and hence can hold values larger than any of the `INT` types could store

|`NUMBER[(P[, *])]`
|`STRUCT`
|`io.debezium.data.VariableScaleDecimal` +
 +
Contains a structure with two fields: `scale` of type `INT32` that contains the scale of the transferred value and `value` of type `BYTES` containing the original value in an unscaled form.

When the `decimal.handling.mode` property is set to `double`, the connector represents `NUMBER` values as Java `double` values with schema type `FLOAT64`.

When the `decimal.handling.mode` property is set to `string`, the connector represents `NUMBER` values as their formatted string representation with schema type `STRING`.

|`NUMBER(P, S \<= 0)`
|`INT8` / `INT16` / `INT32` / `INT64`
|`NUMBER` columns with a scale of 0 represent integer numbers.
A negative scale indicates rounding in Oracle, for example, a scale of -2 causes rounding to hundreds. +
 +
Depending on the precision and scale, one of the following matching Kafka Connect integer type is chosen: +

 * P - S < 3, `INT8` +
 * P - S < 5, `INT16` +
 * P - S < 10, `INT32` +
 * P - S < 19, `INT64` +
 * P - S >= 19, `BYTES` (`org.apache.kafka.connect.data.Decimal`)

When the `decimal.handling.mode` property is set to `double`, the connector represents `NUMBER` values as Java `double` values with schema type `FLOAT64`.

When the `decimal.handling.mode` property is set to `string`, the connector represents `NUMBER` values as their formatted string representation with schema type `STRING`.


|`NUMBER(P, S > 0)`
|`BYTES`
|`org.apache.kafka.connect.data.Decimal`

|`NUMERIC[(P, S)]`
|`BYTES` / `INT8` / `INT16` / `INT32` / `INT64`
|`org.apache.kafka.connect.data.Decimal` if using `BYTES` +
 +
Handled equivalently to `NUMBER` (note that S defaults to 0 for `NUMERIC`).

When the `decimal.handling.mode` property is set to `double`, the connector represents `NUMERIC` values as Java `double` values with schema type `FLOAT64`.

When the `decimal.handling.mode` property is set to `string`, the connector represents `NUMERIC` values as their formatted string representation with schema type `STRING`.

|`SMALLINT`
|`BYTES`
|`org.apache.kafka.connect.data.Decimal` +
 +
`SMALLINT` is mapped in Oracle to NUMBER(38,0) and hence can hold values larger than any of the `INT` types could store

|`REAL`
|`STRUCT`
|`io.debezium.data.VariableScaleDecimal` +
 +
Contains a structure with two fields: `scale` of type `INT32` that contains the scale of the transferred value and `value` of type `BYTES` containing the original value in an unscaled form.

When the `decimal.handling.mode` property is set to `double`, the connector represents `REAL` values as Java `double` values with schema type `FLOAT64`.

When the `decimal.handling.mode` property is set to `string`, the connector represents `REAL` values as their formatted string representation with schema type `STRING`.

|===

[id="oracle-boolean-types"]
=== Boolean types

Oracle does not provide native support for a `BOOLEAN` data type.
However, it is common practice to use other data types with certain semantics to simulate the concept of a logical `BOOLEAN` data type.

To enable you to convert source columns to Boolean data types, {prodname} provides a `NumberOneToBooleanConverter` {link-prefix}:{link-custom-converters}#custom-converters[custom converter] that you can use in one of the following ways:

* Map all `NUMBER(1)` columns to a `BOOLEAN` type.
* Enumerate a subset of columns by using a comma-separated list of regular expressions. +
To use this type of conversion, you must set the xref:oracle-property-converters[`converters`] configuration property with the `selector` parameter, as shown in the following example:
+
[source]
----
converters=boolean
boolean.type=io.debezium.connector.oracle.converters.NumberOneToBooleanConverter
boolean.selector=.*MYTABLE.FLAG,.*.IS_ARCHIVED
----

[id="oracle-temporal-types"]
=== Temporal types

Other than the Oracle `INTERVAL`, `TIMESTAMP WITH TIME ZONE`, and `TIMESTAMP WITH LOCAL TIME ZONE` data types, the way that the connector converts temporal types depends on the value of the `time.precision.mode` configuration property.

When the `time.precision.mode` configuration property is set to `adaptive` (the default), then the connector determines the literal and semantic type for the temporal types based on the column's data type definition so that events _exactly_ represent the values in the database:

[cols="25%a,20%a,55%a",options="header"]
|===
|Oracle data type |Literal type (schema type) |Semantic type (schema name) and Notes

|`DATE`
|`INT64`
|`io.debezium.time.Timestamp` +
 +
Represents the number of milliseconds since the UNIX epoch, and does not include timezone information.

|`INTERVAL DAY[(M)] TO SECOND`
|`FLOAT64`
|`io.debezium.time.MicroDuration` +
 +
The number of micro seconds for a time interval using the `365.25 / 12.0` formula for days per month average. +
 +
`io.debezium.time.Interval` (when `interval.handling.mode` is set to `string`) +
 +
The string representation of the interval value that follows the pattern `P<years>Y<months>M<days>DT<hours>H<minutes>M<seconds>S`, for example,  `P1Y2M3DT4H5M6.78S`.

|`INTERVAL YEAR[(M)] TO MONTH`
|`FLOAT64`
|`io.debezium.time.MicroDuration` +
 +
The number of micro seconds for a time interval using the `365.25 / 12.0` formula for days per month average. +
 +
`io.debezium.time.Interval` (when `interval.handling.mode` is set to `string`) +
 +
The string representation of the interval value that follows the pattern `P<years>Y<months>M<days>DT<hours>H<minutes>M<seconds>S`, for example,  `P1Y2M3DT4H5M6.78S`.

|`TIMESTAMP(0 - 3)`
|`INT64`
|`io.debezium.time.Timestamp` +
 +
Represents the number of milliseconds since the UNIX epoch, and does not include timezone information.

|`TIMESTAMP, TIMESTAMP(4 - 6)`
|`INT64`
|`io.debezium.time.MicroTimestamp` +
 +
Represents the number of microseconds since the UNIX epoch, and does not include timezone information.

|`TIMESTAMP(7 - 9)`
|`INT64`
|`io.debezium.time.NanoTimestamp` +
 +
Represents the number of nanoseconds since the UNIX epoch, and does not include timezone information.

|`TIMESTAMP WITH TIME ZONE`
|`STRING`
|`io.debezium.time.ZonedTimestamp` +
 +
A string representation of a timestamp with timezone information.

|`TIMESTAMP WITH LOCAL TIME ZONE`
|`STRING`
|`io.debezium.time.ZonedTimestamp` +
 +
A string representation of a timestamp in UTC.

|===

When the `time.precision.mode` configuration property is set to `connect`, then the connector uses the predefined Kafka Connect logical types.
This can be useful when consumers only know about the built-in Kafka Connect logical types and are unable to handle variable-precision time values.
Because the level of precision that Oracle supports exceeds the level that the logical types in Kafka Connect support, if you set `time.precision.mode` to `connect`, *a loss of precision* results when the _fractional second precision_ value of a database column is greater than 3:

[cols="25%a,20%a,55%a",options="header"]
|===
|Oracle data type |Literal type (schema type) |Semantic type (schema name) and Notes

|`DATE`
|`INT32`
|`org.apache.kafka.connect.data.Date` +
 +
Represents the number of days since the UNIX epoch.

|`INTERVAL DAY[(M)] TO SECOND`
|`FLOAT64`
|`io.debezium.time.MicroDuration` +
 +
The number of micro seconds for a time interval using the `365.25 / 12.0` formula for days per month average. +
 +
`io.debezium.time.Interval` (when `interval.handling.mode` is set to `string`) +
 +
The string representation of the interval value that follows the pattern `P<years>Y<months>M<days>DT<hours>H<minutes>M<seconds>S`, for example,  `P1Y2M3DT4H5M6.78S`.

|`INTERVAL YEAR[(M)] TO MONTH`
|`FLOAT64`
|`io.debezium.time.MicroDuration` +
 +
The number of micro seconds for a time interval using the `365.25 / 12.0` formula for days per month average. +
 +
`io.debezium.time.Interval` (when `interval.handling.mode` is set to `string`) +
 +
The string representation of the interval value that follows the pattern `P<years>Y<months>M<days>DT<hours>H<minutes>M<seconds>S`, for example,  `P1Y2M3DT4H5M6.78S`.

|`TIMESTAMP(0 - 3)`
|`INT64`
|`org.apache.kafka.connect.data.Timestamp` +
 +
Represents the number of milliseconds since the UNIX epoch, and does not include timezone information.

|`TIMESTAMP(4 - 6)`
|`INT64`
|`org.apache.kafka.connect.data.Timestamp` +
 +
Represents the number of milliseconds since the UNIX epoch, and does not include timezone information.

|`TIMESTAMP(7 - 9)`
|`INT64`
|`org.apache.kafka.connect.data.Timestamp` +
 +
Represents the number of milliseconds since the UNIX epoch, and does not include timezone information.

|`TIMESTAMP WITH TIME ZONE`
|`STRING`
|`io.debezium.time.ZonedTimestamp` +
 +
A string representation of a timestamp with timezone information.

|`TIMESTAMP WITH LOCAL TIME ZONE`
|`STRING`
|`io.debezium.time.ZonedTimestamp` +
 +
A string representation of a timestamp in UTC.

|===

[id="oracle-rowid-types"]
=== ROWID types

The following table describes how the connector maps ROWID (row address) data types.

.Mappings for Oracle ROWID data types
[cols="20%a,15%a,55%a",options="header"]
|===
|Oracle Data Type
|Literal type (schema type)
|Semantic type (schema name) and Notes

|`ROWID`
|`STRING`
|
ifdef::community[]
_This data type is not supported when using Oracle XStream._
endif::community[]
ifdef::product[]
n/a
endif::product[]

|`UROWID`
|n/a
|_This data type is not supported_.

|===

[id="oracle-user-defined-types"]
=== User-defined types

Oracle enables you to define custom data types to provide flexibility when the built-in data types do not satisfy your requirements.
There are a several user-defined types such as Object types, REF data types, Varrays, and Nested Tables.
At this time, you cannot use the {prodname} Oracle connector with any of these user-defined types.

[id="oracle-supplied-types"]
=== Oracle-supplied types

Oracle provides SQL-based interfaces that you can use to define new types when the built-in or ANSI-supported types are insufficient.
Oracle offers several commonly used data types to serve a broad array of purposes such as *Any*, *XML*, or *Spatial* types.
At this time, you cannot use the {prodname} Oracle connector with any of these data types.

[[oracle-default-values]]
=== Default Values
If a default value is specified for a column in the database schema, the Oracle connector will attempt to propagate this value to the schema of the corresponding Kafka record field.
Most common data types are supported, including:

* Character types (`CHAR`, `NCHAR`, `VARCHAR`, `VARCHAR2`, `NVARCHAR`, `NVARCHAR2`)
* Numeric types (`INTEGER`, `NUMERIC`, etc.)
* Temporal types (`DATE`, `TIMESTAMP`, `INTERVAL`, etc.)

If a temporal type uses a function call such as `TO_TIMESTAMP` or `TO_DATE` to represent the default value, the connector will resolve the default value by making an additional database call to evaluate the function.
For example, if a `DATE` column is defined with the default value of `TO_DATE('2021-01-02', 'YYYY-MM-DD')`, the column's default value will be the number of days since the UNIX epoch for that date or `18629` in this case.

If a temporal type uses the `SYSDATE` constant to represent the default value, the connector will resolve this based on whether the column is defined as `NOT NULL` or `NULL`.
If the column is nullable, no default value will be set; however, if the column isn't nullable then the default value will be resolved as either `0` (for `DATE` or `TIMESTAMP(n)` data types) or `1970-01-01T00:00:00Z` (for `TIMESTAMP WITH TIME ZONE` or `TIMESTAMP WITH LOCAL TIME ZONE` data types).
The default value type will be numeric except if the column is a `TIMESTAMP WITH TIME ZONE` or `TIMESTAMP WITH LOCAL TIME ZONE` in which case its emitted as a string.

// Type: assembly
// ModuleID: setting-up-oracle-to-work-with-debezium
//Title: Setting up Oracle to work with {prodname}
[[setting-up-oracle]]
== Setting up Oracle

The following steps are necessary to set up Oracle for use with the {prodname} Oracle connector.
These steps assume the use of the multi-tenancy configuration with a container database and at least one pluggable database.
If you do not intend to use a multi-tenant configuration, it might be necessary to adjust the following steps.

ifdef::community[]
For information about using Vagrant to set up Oracle in a virtual machine, see the https://github.com/debezium/oracle-vagrant-box/[Debezium Vagrant Box for Oracle database] GitHub repository.
endif::community[]
ifdef::product[]

For details about setting up Oracle for use with the {prodname} connector, see the following sections:

* xref:compatibility-of-the-debezium-oracle-connector-with-oracle-installation-types[]
* xref:schemas-that-the-debezium-oracle-connector-excludes-when-capturing-change-events[]
* xref:preparing-oracle-databases-for-use-with-debezium[]
* xref:resizing-oracle-redo-logs-to-accommodate-the-data-dictionary[]
* xref:creating-an-oracle-user-for-the-debezium-oracle-connector[]
* xref:support-for-oracle-standby-databases[]

endif::product[]
// Type: concept
// Title: Compatibility of the {prodname} Oracle connector with Oracle installation types
[id="compatibility-of-the-debezium-oracle-connector-with-oracle-installation-types"]
=== Compatibility with Oracle installation types


An Oracle database can be installed either as a standalone instance or using Oracle Real Application Cluster (RAC).
The {prodname} Oracle connector is compatible with both types of installation.

ifdef::product[]
[IMPORTANT]
====
Using the connector in a RAC environment is a Technology Preview feature only.
Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete.
Red Hat does not recommend using them in production.
These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see link:https://access.redhat.com/support/offerings/techpreview[https://access.redhat.com/support/offerings/techpreview].
====
endif::product[]
// Type: concept
// Title: Schemas that the {prodname} Oracle connector excludes when capturing change events
[id="schemas-that-the-debezium-oracle-connector-excludes-when-capturing-change-events"]
=== Schemas excluded from capture

When the {prodname} Oracle connector captures tables, it automatically excludes tables from the following schemas:

* `appqossys`
* `audsys`
* `ctxsys`
* `dvsys`
* `dbsfwuser`
* `dbsnmp`
* `qsmadmin_internal`
* `lbacsys`
* `mdsys`
* `ojvmsys`
* `olapsys`
* `orddata`
* `ordsys`
* `outln`
* `sys`
* `system`
* `wmsys`
* `xdb`

To enable the connector to capture changes from a table, the table must use a schema that is not named in the preceding list.

// Type: procedure
// ModuleID: preparing-oracle-databases-for-use-with-debezium
// Title: Preparing Oracle databases for use with {prodname}
=== Preparing the database

.Configuration needed for Oracle LogMiner
[source,indent=0]
----
ORACLE_SID=ORACLCDB dbz_oracle sqlplus /nolog

CONNECT sys/top_secret AS SYSDBA
alter system set db_recovery_file_dest_size = 10G;
alter system set db_recovery_file_dest = '/opt/oracle/oradata/recovery_area' scope=spfile;
shutdown immediate
startup mount
alter database archivelog;
alter database open;
-- Should now "Database log mode: Archive Mode"
archive log list

exit;
----

To enable {prodname} to capture the _before_ state of changed database rows, you must also enable supplemental logging for captured tables or for the entire database.
The following example illustrates how to configure supplemental logging for all columns in a single `inventory.customers` table.

[source,indent=0]
----
ALTER TABLE inventory.customers ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;
----

Enabling supplemental logging for all table columns increases the volume of the Oracle redo logs.
To prevent excessive growth in the size of the logs, apply the preceding configuration selectively.

Minimal supplemental logging must be enabled at the database level and can be configured as follows.

[source,indent=0]
----
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
----

// Type: concept
// Title: Resizing Oracle redo logs to accommodate the data dictionary
// ModuleID: resizing-oracle-redo-logs-to-accommodate-the-data-dictionary
[id="oracle-redo-log-sizing"]
=== Redo log sizing

Depending on the database configuration, the size and number of redo logs might not be sufficient to achieve acceptable performance.
Before you set up the {prodname} Oracle connector, ensure that the capacity of the redo logs is sufficient to support the database.

The capacity of the redo logs for a database must be sufficient to store its data dictionary.
In general, the size of the data dictionary increases with the number of tables and columns in the database.
If the redo log lacks sufficient capacity, both the database and the {prodname} connector might experience performance problems.

Consult with your database administrator to evaluate whether the database might require increased log capacity.

// Type: procedure
// ModuleID: creating-an-oracle-user-for-the-debezium-oracle-connector
// Title: Creating an Oracle user for the {prodname} Oracle connector
[id="creating-users-for-the-connector"]
=== Creating users for the connector

For the {prodname} Oracle connector to capture change events, it must run as an Oracle LogMiner user that has specific permissions.
The following example shows the SQL for creating an Oracle user account for the connector in a multi-tenant database model.

[WARNING]
====
The connector captures database changes that are made by its own Oracle user account.
However, it does not capture changes that are made by the `SYS` or `SYSTEM` user accounts.
====

[[oracle-create-users-logminer]]
.Creating the connector's LogMiner user
[source,sql,indent=0]
----
sqlplus sys/top_secret@//localhost:1521/ORCLCDB as sysdba
  CREATE TABLESPACE logminer_tbs DATAFILE '/opt/oracle/oradata/ORCLCDB/logminer_tbs.dbf'
    SIZE 25M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED;
  exit;

sqlplus sys/top_secret@//localhost:1521/ORCLPDB1 as sysdba
  CREATE TABLESPACE logminer_tbs DATAFILE '/opt/oracle/oradata/ORCLCDB/ORCLPDB1/logminer_tbs.dbf'
    SIZE 25M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED;
  exit;

sqlplus sys/top_secret@//localhost:1521/ORCLCDB as sysdba

  CREATE USER c##dbzuser IDENTIFIED BY dbz
    DEFAULT TABLESPACE logminer_tbs
    QUOTA UNLIMITED ON logminer_tbs
    CONTAINER=ALL;

  GRANT CREATE SESSION TO c##dbzuser CONTAINER=ALL; <1>
  GRANT SET CONTAINER TO c##dbzuser CONTAINER=ALL; <2>
  GRANT SELECT ON V_$DATABASE to c##dbzuser CONTAINER=ALL; <3>
  GRANT FLASHBACK ANY TABLE TO c##dbzuser CONTAINER=ALL; <4>
  GRANT SELECT ANY TABLE TO c##dbzuser CONTAINER=ALL; <5>
  GRANT SELECT_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL; <6>
  GRANT EXECUTE_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL; <7>
  GRANT SELECT ANY TRANSACTION TO c##dbzuser CONTAINER=ALL; <8>
  GRANT LOGMINING TO c##dbzuser CONTAINER=ALL; <9>

  GRANT CREATE TABLE TO c##dbzuser CONTAINER=ALL; <10>
  GRANT LOCK ANY TABLE TO c##dbzuser CONTAINER=ALL; <11>
  GRANT CREATE SEQUENCE TO c##dbzuser CONTAINER=ALL; <12>

  GRANT EXECUTE ON DBMS_LOGMNR TO c##dbzuser CONTAINER=ALL; <13>
  GRANT EXECUTE ON DBMS_LOGMNR_D TO c##dbzuser CONTAINER=ALL; <14>

  GRANT SELECT ON V_$LOG TO c##dbzuser CONTAINER=ALL; <15>
  GRANT SELECT ON V_$LOG_HISTORY TO c##dbzuser CONTAINER=ALL; <16>
  GRANT SELECT ON V_$LOGMNR_LOGS TO c##dbzuser CONTAINER=ALL; <17>
  GRANT SELECT ON V_$LOGMNR_CONTENTS TO c##dbzuser CONTAINER=ALL; <18>
  GRANT SELECT ON V_$LOGMNR_PARAMETERS TO c##dbzuser CONTAINER=ALL; <19>
  GRANT SELECT ON V_$LOGFILE TO c##dbzuser CONTAINER=ALL; <20>
  GRANT SELECT ON V_$ARCHIVED_LOG TO c##dbzuser CONTAINER=ALL; <21>
  GRANT SELECT ON V_$ARCHIVE_DEST_STATUS TO c##dbzuser CONTAINER=ALL; <22>
  GRANT SELECT ON V_$TRANSACTION TO c##dbzuser CONTAINER=ALL; <23>

  exit;
----

.Descriptions of permissions / grants
[cols="1,4,5",options="header"]
|===
|Item |Role name |Description

|1
|CREATE SESSION
|Enables the connector to connect to Oracle.

|2
|SET CONTAINER
|Enables the connector to switch between pluggable databases.
This is only required when the Oracle installation has container database support (CDB) enabled.

|3
|SELECT ON V_$DATABASE
|Enables the connector to read the `V$DATABASE` table.

|4
|FLASHBACK ANY TABLE
|Enables the connector to perform Flashback queries, which is how the connector performs the initial snapshot of data.

|5
|SELECT ANY TABLE
|Enables the connector to read any table.

|6
|SELECT_CATALOG_ROLE
|Enables the connector to read the data dictionary, which is needed by Oracle LogMiner sessions.

|7
|EXECUTE_CATALOG_ROLE
|Enables the connector to write the data dictionary into the Oracle redo logs, which is needed to track schema changes.

|8
|SELECT ANY TRANSACTION
|Enables the snapshot process to perform a Flashback snapshot query against any transaction.
When `FLASHBACK ANY TABLE` is granted, this should also be granted.

|9
|LOGMINING
|This role was added in newer versions of Oracle as a way to grant full access to Oracle LogMiner and its
packages.  On older versions of Oracle that don't have this role, you can ignore this grant.

|10
|CREATE TABLE
|Enables the connector to create its flush table in its default tablespace.
The flush table allows the connector to explicitly control flushing of the LGWR internal buffers to disk.

|11
|LOCK ANY TABLE
|Enables the connector to lock tables during schema snapshot.
If snapshot locks are explicitly disabled via configuration, this grant can be safely ignored.

|12
|CREATE ANY SEQUENCE
|Enables the connector to create a sequence in its default tablespace.

|13
|EXECUTE ON DBMS_LOGMNR
|Enables the connector to run methods in the `DBMS_LOGMNR` package.
This is required to interact with Oracle LogMiner.
On newer versions of Oracle this is granted via the `LOGMINING` role but on older versions, this must be explicitly granted.

|14
|EXECUTE ON DBMS_LOGMNR_D
|Enables the connector to run methods in the `DBMS_LOGMNR_D` package.
This is required to interact with Oracle LogMiner.
On newer versions of Oracle this is granted via the `LOGMINING` role but on older versions, this must be explicitly granted.

|15 to 23
|SELECT ON V_$....
|Enables the connector to read these tables.
The connector must be able to read information about the Oracle redo and archive logs, and the current transaction state, to prepare the Oracle LogMiner session.
Without these grants, the connector cannot operate.

|===

// Type: concept
// Title: Support for Oracle standby databases
[id="support-for-oracle-standby-databases"]
=== Standby databases
ifdef::product[]
The {prodname} Oracle connector cannot be used with Oracle physical or logical standby databases.
endif::product[]
ifdef::community[]
An Oracle database can be configured with either a physical or a logical standby environment to provide for recovery after of a production failure.
At this time, the {prodname} Oracle connector cannot use a physical or logical standby database as the change event source.
There is an open https://issues.redhat.com/browse/DBZ-3866[Jira issue] to investigate this support.

=== Failover databases

It is customary for a logical or physical standby to exist in the case of an Oracle production failure.
When a failure occurs and the standby instance is promoted to production, the database must be opened for read/write transactions before the {prodname} Oracle connector can connect to the database.

In the case of a physical standby, the standby is an exact copy of production, which implies that the SCN values are identical.
When using a physical standby, it is sufficient to reconfigure the {prodname} Oracle connector to use the hostname of the standby once the database is open.

In the case of a logical standby, the standby is not an exact copy of the production database, so the SCN offsets in the standby differ from those in the production database.
If you use a logical standby, to help ensure that {prodname} does not miss any change events, after the database is open, configure a new connector and perform a new database snapshot.
endif::community[]
// Type: assembly
// ModuleID: deployment-of-debezium-oracle-connectors
// Title: Deployment of {prodname} Oracle connectors
[[oracle-deploying-a-connector]]
== Deployment

ifdef::community[]
To deploy a {prodname} Oracle connector, you install the {prodname} Oracle connector archive, configure the connector, and start the connector by adding its configuration to Kafka Connect.

.Prerequisites
* link:https://zookeeper.apache.org/[Apache ZooKeeper], link:http://kafka.apache.org/[Apache Kafka], and link:{link-kafka-docs}.html#connect[Kafka Connect] are installed.
* Oracle Database is installed, and is xref:{link-oracle-connector}#setting-up-oracle[configured to work with the {prodname} connector].

.Procedure

. Download the {prodname} https://repo1.maven.org/maven2/io/debezium/debezium-connector-oracle/{debezium-version}/debezium-connector-oracle-{debezium-version}-plugin.tar.gz[Oracle connector plug-in archive].
. Extract the files into your Kafka Connect environment.
. Download the link:https://repo1.maven.org/maven2/com/oracle/database/jdbc/ojdbc8/{ojdbc8-version}/ojdbc8-{ojdbc8-version}.jar[JDBC driver for Oracle] from Maven Central and extract the downloaded driver file to the directory that contains the {prodname} Oracle connector JAR file.
. Add the directory with the JAR files to {link-kafka-docs}/#connectconfigs[Kafka Connect's `plugin.path`].
. Restart your Kafka Connect process to pick up the new JAR files.

.Next steps

* xref:{link-oracle-connector}#oracle-example-configuration[Configure the connector] and xref:{link-oracle-connector}#oracle-adding-connector-configuration[add the configuration to your Kafka Connect cluster.]

endif::community[]

ifdef::product[]
You can use either of the following methods to deploy a {prodname} Oracle connector:

* xref:openshift-streams-oracle-connector-deployment[Use {StreamsName} to automatically create an image that includes the connector plug-in].
+
This is the preferred method.
* xref:deploying-debezium-oracle-connectors[Build a custom Kafka Connect container image from a Dockerfile].

[IMPORTANT]
====
Due to licensing requirements, the {prodname} Oracle connector archive does not include the Oracle JDBC driver that the connector requires to connect to an Oracle database.
To enable the connector to access the database, you must add the driver to your connector environment.
For more information, see xref:obtaining-the-oracle-jdbc-driver[Obtaining the Oracle JDBC driver].
====

.Additional resources

* xref:descriptions-of-debezium-oracle-connector-configuration-properties[]

// Type: procedure
[id="obtaining-the-oracle-jdbc-driver"]
=== Obtaining the Oracle JDBC driver

Due to licensing requirements, the Oracle JDBC driver file that {prodname} requires to connect to an Oracle database is not included in the {prodname} Oracle connector archive.
ifdef::product[]
The driver is available for download from Maven Central.
Depending on the deployment method that you use, you retrieve the driver by adding a command to the Kafka Connect custom resource or to the Dockerfile that you use to build the connector image.

* If you use {StreamsName} to add the connector to your Kafka Connect image, add the Maven Central location for the driver to `builds.plugins.artifact.url` in the `KafkaConnect` custom resource as shown in xref:using-streams-to-deploy-debezium-oracle-connectors[].
* If you use a Dockerfile to build a container image for the connector, insert a `curl` command in the Dockerfile to specify the URL for downloading the required driver file from Maven Central.
For more information, see xref:deploying-debezium-oracle-connectors[Deploying a {prodname} Oracle connector by building a custom Kafka Connect container image from a Dockerfile].

endif::product[]
ifdef::community[]

NOTE: If you use the {prodname} Oracle connector with Oracle XStream, obtain the JDBC driver as part of the Oracle Instant Client package.
For more information, see xref:obtaining-oracle-jdbc-driver-and-xstreams-api-files[].

.Procedure

. From a browser, link:https://repo1.maven.org/maven2/com/oracle/database/jdbc/ojdbc8/{ojdbc8-version}/ojdbc8-{ojdbc8-version}.jar[download the 'ojdbc8.jar' from Maven Central].
. Copy the downloaded driver file to the directory that contains the {prodname} Oracle connector JAR file (`debezium-connector-oracle-{debezium-version}.jar`).
endif::community[]


// Type: concept
[id="openshift-streams-oracle-connector-deployment"]
=== {prodname} Oracle connector deployment using {StreamsName}

include::{partialsdir}/modules/all-connectors/con-connector-streams-deployment.adoc[leveloffset=+1]

// Type: procedure
[id="using-streams-to-deploy-debezium-oracle-connectors"]
=== Using {StreamsName} to deploy a {prodname} Oracle connector
include::{partialsdir}/modules/all-connectors/proc-using-streams-to-deploy-a-debezium-connector.adoc[leveloffset=+1]

// Type: procedure
[id="deploying-debezium-oracle-connectors"]
=== Deploying a {prodname} Oracle connector by building a custom Kafka Connect container image from a Dockerfile

To deploy a {prodname} Oracle connector, you must build a custom Kafka Connect container image that contains the {prodname} connector archive, and then push this container image to a container registry.
You then need to create the following custom resources (CRs):

* A `KafkaConnect` CR that defines your Kafka Connect instance.
  The `image` property in the CR specifies the name of the container image that you create to run your {prodname} connector.
  You apply this CR to the OpenShift instance where link:https://access.redhat.com/products/red-hat-amq#streams[Red Hat {StreamsName}] is deployed.
  {StreamsName} offers operators and images that bring Apache Kafka to OpenShift.

* A `KafkaConnector` CR that defines your {prodname} Oracle connector.
  Apply this CR to the same OpenShift instance where you apply the `KafkaConnect` CR.

.Prerequisites

* Oracle Database is running and you completed the steps to {LinkDebeziumUserGuide}#setting-up-oracle-for-use-with-the-debezium-oracle-connector[set up Oracle to work with a {prodname} connector].

* {StreamsName} is deployed on OpenShift and is running Apache Kafka and Kafka Connect.
  For more information, see link:{LinkDeployStreamsOpenShift}[{NameDeployStreamsOpenShift}]

* Podman or Docker is installed.

* You have an account and permissions to create and manage containers in the container registry (such as `quay.io` or `docker.io`) to which you plan to add the container that will run your {prodname} connector.

* The Kafka Connect server has access to Maven Central to download the required JDBC driver for Oracle.
  You can also use a local copy of the driver, or one that is available from a local Maven repository or other HTTP server.
+
For more information, see xref:{link-oracle-connector}#obtaining-the-oracle-jdbc-driver[Obtaining the Oracle JDBC driver].

.Procedure

. Create the {prodname} Oracle container for Kafka Connect:

.. Create a Dockerfile that uses `{DockerKafkaConnect}` as the base image.
For example, from a terminal window, enter the following command:
+
[source,shell,subs="+attributes,+quotes"]
----
cat <<EOF >debezium-container-for-oracle.yaml // <1>
FROM {DockerKafkaConnect}
USER root:root
RUN mkdir -p /opt/kafka/plugins/debezium // <2>
RUN curl -O {red-hat-maven-repository}debezium/debezium-connector-{connector-file}/{debezium-version}-redhat-__<build_number>__/debezium-connector-{connector-file}-{debezium-version}-redhat-__<build_number>__-plugin.zip
RUN curl -O https://repo1.maven.org/maven2/com/oracle/ojdbc/ojdbc8/{ojdbc8-version}/ojdbc8-{ojdbc8-version}.jar
USER 1001
EOF
----
<1> You can specify any file name that you want.
<2> Specifies the path to your Kafka Connect plug-ins directory. If your Kafka Connect plug-ins directory is in a different location, replace this path with the actual path of your directory.
+
The command creates a Dockerfile with the name `debezium-container-for-oracle.yaml` in the current directory.

.. Build the container image from the `debezium-container-for-oracle.yaml` Docker file that you created in the previous step.
From the directory that contains the file, open a terminal window and enter one of the following commands:
+
[source,shell,options="nowrap"]
----
podman build -t debezium-container-for-oracle:latest .
----
+
[source,shell,options="nowrap"]
----
docker build -t debezium-container-for-oracle:latest .
----
The preceding commands build a container image with the name `debezium-container-for-oracle`.

.. Push your custom image to a container registry, such as quay.io or an internal container registry.
The container registry must be available to the OpenShift instance where you want to deploy the image.
Enter one of the following commands:
+
[source,shell,subs="+quotes"]
----
podman push _<myregistry.io>_/debezium-container-for-oracle:latest
----
+
[source,shell,subs="+quotes"]
----
docker push _<myregistry.io>_/debezium-container-for-oracle:latest
----

.. Create a new {prodname} Oracle KafkaConnect custom resource (CR).
For example, create a KafkaConnect CR with the name `dbz-connect.yaml` that specifies `annotations` and `image` properties as shown in the following example:
+
[source,yaml,subs="+attributes"]
----
apiVersion: {KafkaConnectApiVersion}
kind: KafkaConnect
metadata:
  name: my-connect-cluster
  annotations:
    strimzi.io/use-connector-resources: "true" // <1>
spec:
  #...
  image: debezium-container-for-oracle  // <2>
----
<1>  `metadata.annotations` indicates to the Cluster Operator that KafkaConnector resources are used to configure connectors in this Kafka Connect cluster.
<2>  `spec.image` specifies the name of the image that you created to run your {prodname} connector.
This property overrides the `STRIMZI_DEFAULT_KAFKA_CONNECT_IMAGE` variable in the Cluster Operator

.. Apply the `KafkaConnect` CR to the OpenShift Kafka Connect environment by entering the following command:
+
[source,shell,options="nowrap"]
----
oc create -f dbz-connect.yaml
----
+
The command adds a Kafka Connect instance that specifies the name of the image that you created to run your {prodname} connector.

. Create a `KafkaConnector` custom resource that configures your {prodname} Oracle connector instance.
+
You configure a {prodname} Oracle connector in a `.yaml` file that specifies the configuration properties for the connector.
The connector configuration might instruct {prodname} to produce events for a subset of the schemas and tables, or it might set properties so that {prodname} ignores, masks, or truncates values in specified columns that are sensitive, too large, or not needed.
+
The following example configures a {prodname} connector that connects to an Oracle host IP address, on port `1521`.
This host has a database named `ORCLCDB`, and `server1` is the server's logical name.
+
.Oracle `inventory-connector.yaml`
[source,yaml,subs="+attributes,+quotes",options="nowrap"]
----
apiVersion: {KafkaConnectorApiVersion}
kind: KafkaConnector
metadata:
  name: inventory-connector // <1>
  labels:
    strimzi.io/cluster: my-connect-cluster
  annotations:
    strimzi.io/use-connector-resources: 'true'
spec:
  class: io.debezium.connector.oracle.OracleConnector // <2>
  config:
    database.hostname: _<oracle_ip_address>_ // <3>
    database.port: 1521 // <4>
    database.user: c##dbzuser // <5>
    database.password: dbz // <6>
    database.dbname: ORCLCDB // <7>
    database.pdb.name : ORCLPDB1, <8>
    topic.prefix: server1 // <9>
    schema.history.internal.kafka.bootstrap.servers: kafka:9092 // <10>
    schema.history.internal.kafka.topic: schema-changes.inventory // <11>
----
+
.Descriptions of connector configuration settings
[cols="1,7",options="header",subs="+attributes"]
|===
|Item |Description

|1
|The name of our connector when we register it with a Kafka Connect service.

|2
|The name of this Oracle connector class.

|3
|The address of the Oracle instance.

|4
|The port number of the Oracle instance.

|5
|The name of the Oracle user, as specified in xref:{link-oracle-connector}#creating-users-for-the-connector[Creating users for the connector].

|6
|The password for the Oracle user, as specified in xref:{link-oracle-connector}#creating-users-for-the-connector[Creating users for the connector].

|7
|The name of the database to capture changes from.

|8
|The name of the Oracle pluggable database that the connector captures changes from. Used in container database (CDB) installations only.

|9
|Topic prefix identifies and provides a namespace for the Oracle database server from which the connector captures changes.

|10
|The list of Kafka brokers that this connector uses to write and recover DDL statements to the database schema history topic.

|11
|The name of the database schema history topic where the connector writes and recovers DDL statements. This topic is for internal use only and should not be used by consumers.

|===

. Create your connector instance with Kafka Connect.
  For example, if you saved your `KafkaConnector` resource in the `inventory-connector.yaml` file, you would run the following command:
+
[source,shell,options="nowrap"]
----
oc apply -f inventory-connector.yaml
----
+
The preceding command registers `inventory-connector` and the connector starts to run against the `server1` database as defined in the `KafkaConnector` CR.
endif::product[]

ifdef::community[]
[[oracle-example-configuration]]
=== {prodname} Oracle connector configuration

Typically, you register a {prodname} Oracle connector by submitting a JSON request that specifies the configuration properties for the connector.
The following example shows a JSON request for registering an instance of the {prodname} Oracle connector with logical name `server1` at port 1521:

You can choose to produce events for a subset of the schemas and tables in a database.
Optionally, you can ignore, mask, or truncate columns that contain sensitive data, that are larger than a specified size, or that you do not need.

.Example: {prodname} Oracle connector configuration
[source,json,indent=0,subs="+quotes"]
----
{
    "name": "inventory-connector",  // <1>
    "config": {
        "connector.class" : "io.debezium.connector.oracle.OracleConnector",  // <2>
        "database.hostname" : "<ORACLE_IP_ADDRESS>",  // <3>
        "database.port" : "1521",  // <4>
        "database.user" : "c##dbzuser",  // <5>
        "database.password" : "dbz",   // <6>
        "database.dbname" : "ORCLCDB",  // <7>
        "topic.prefix" : "server1",  // <8>
        "tasks.max" : "1",  // <9>
        "database.pdb.name" : "ORCLPDB1",  // <10>
        "schema.history.internal.kafka.bootstrap.servers" : "kafka:9092", // <11>
        "schema.history.internal.kafka.topic": "schema-changes.inventory"  // <12>
    }
}
----
<1> The name that is assigned to the connector when you register it with a Kafka Connect service.
<2> The name of this Oracle connector class.
<3> The address of the Oracle instance.
<4> The port number of the Oracle instance.
<5> The name of the Oracle user, as specified in xref:{link-oracle-connector}#creating-users-for-the-connector[Creating users for the connector].
<6> The password for the Oracle user, as specified in xref:{link-oracle-connector}#creating-users-for-the-connector[Creating users for the connector].
<7> The name of the database to capture changes from.
<8> Topic prefix that identifies and provides a namespace for the Oracle database server from which the connector captures changes.
<9> The maximum number of tasks to create for this connector.
<10> The name of the Oracle pluggable database that the connector captures changes from. Used in container database (CDB) installations only.
<11> The list of Kafka brokers that this connector uses to write and recover DDL statements to the database schema history topic.
<12> The name of the database schema history topic where the connector writes and recovers DDL statements. This topic is for internal use only and should not be used by consumers.

In the previous example, the `database.hostname` and `database.port` properties are used to define the connection to the database host.
However, in more complex Oracle deployments, or in deployments that use Transparent Network Substrate (TNS) names, you can use an alternative method in which you specify a JDBC URL.

The following JSON example shows the same configuration as in the preceding example, except that it uses a JDBC URL to connect to the database.

.Example: {prodname} Oracle connector configuration that uses a JDBC URL to connect to the database
[source,json,indent=0]
----
{
    "name": "inventory-connector",
    "config": {
        "connector.class" : "io.debezium.connector.oracle.OracleConnector",
        "tasks.max" : "1",
        "topic.prefix" : "server1",
        "database.user" : "c##dbzuser",
        "database.password" : "dbz",
        "database.url": "jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(LOAD_BALANCE=OFF)(FAILOVER=ON)(ADDRESS=(PROTOCOL=TCP)(HOST=<oracle ip 1>)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=<oracle ip 2>)(PORT=1521)))(CONNECT_DATA=SERVICE_NAME=)(SERVER=DEDICATED)))",
        "database.dbname" : "ORCLCDB",
        "database.pdb.name" : "ORCLPDB1",
        "schema.history.internal.kafka.bootstrap.servers" : "kafka:9092",
        "schema.history.internal.kafka.topic": "schema-changes.inventory"
    }
}
----
endif::community[]


For the complete list of the configuration properties that you can set for the {prodname} Oracle connector, see xref:{link-oracle-connector}#oracle-connector-properties[Oracle connector properties].

ifdef::community[]
You can send this configuration with a `POST` command to a running Kafka Connect service.
The service records the configuration and starts a connector task that performs the following operations:

* Connects to the Oracle database.
* Reads the redo log.
* Records change events to Kafka topics.

[[oracle-adding-connector-configuration]]
=== Adding connector configuration

To start running a {prodname} Oracle connector, create a connector configuration, and add the configuration to your Kafka Connect cluster.

.Prerequisites

* xref:{link-oracle-connector}#setting-up-oracle[Oracle is configured for use with {prodname}].
* The {prodname} Oracle connector is installed.

.Procedure

. Create a xref:{link-oracle-connector}#oracle-example-configuration[configuration] for the Oracle connector.

. Use the link:{link-kafka-docs}/#connect_rest[Kafka Connect REST API] to add that connector configuration to your Kafka Connect cluster.
endif::community[]

.Results

After the connector starts, it xref:{link-oracle-connector}#oracle-snapshots[performs a consistent snapshot] of the Oracle databases that the connector is configured for.
The connector then starts generating data change events for row-level operations and streaming the change event records to Kafka topics.

// Type: concept
// ModuleID: configuration-of-container-databases-and-non-container-databases
// Title: Configuration of container databases and non-container-databases
[[pluggable-vs-non-pluggable-databases]]
=== Pluggable vs Non-Pluggable databases
[[oracle-database-mode]]


Oracle Database supports the following deployment types:

Container database (CDB):: A database that can contain multiple pluggable databases (PDBs).
Database clients connect to each PDB as if it were a standard, non-CDB database.

Non-container database (non-CDB):: A standard Oracle database, which does not support the creation of pluggable databases.


ifdef::community[]


.Example: {prodname} connector configuration for CDB deployments
[source,json,indent=0]
----
{
    "config": {
        "connector.class" : "io.debezium.connector.oracle.OracleConnector",
        "tasks.max" : "1",
        "topic.prefix" : "server1",
        "database.hostname" : "<oracle ip>",
        "database.port" : "1521",
        "database.user" : "c##dbzuser",
        "database.password" : "dbz",
        "database.dbname" : "ORCLCDB",
        "database.pdb.name" : "ORCLPDB1",
        "schema.history.internal.kafka.bootstrap.servers" : "kafka:9092",
        "schema.history.internal.kafka.topic": "schema-changes.inventory"
    }
}
----

[IMPORTANT]
====
When you configure a {prodname} Oracle connector for use with an Oracle CDB, you must specify a value for the property `database.pdb.name`, which names the PDB that you want the connector to capture changes from.
For non-CDB installation, do *not* specify the `database.pdb.name` property.
====

.Example: {prodname} Oracle connector configuration for non-CDB deployments
[source,json,indent=0]
----
{
    "config": {
        "connector.class" : "io.debezium.connector.oracle.OracleConnector",
        "tasks.max" : "1",
        "topic.prefix" : "server1",
        "database.hostname" : "<oracle ip>",
        "database.port" : "1521",
        "database.user" : "c##dbzuser",
        "database.password" : "dbz",
        "database.dbname" : "ORCLCDB",
        "schema.history.internal.kafka.bootstrap.servers" : "kafka:9092",
        "schema.history.internal.kafka.topic": "schema-changes.inventory"
    }
}
----

endif::community[]
ifdef::product[]
// Type: procedure
[id="verifying-that-the-debezium-oracle-connector-is-running"]
=== Verifying that the {prodname} Oracle connector is running

include::{partialsdir}/modules/all-connectors/proc-verifying-the-connector-deployment.adoc[leveloffset=+1]

endif::product[]

// Type: reference
// Title: Descriptions of {prodname} Oracle connector configuration properties
// ModuleID: descriptions-of-debezium-oracle-connector-configuration-properties
[[oracle-connector-properties]]
== Connector properties

The {prodname} Oracle connector has numerous configuration properties that you can use to achieve the right connector behavior for your application.
Many properties have default values.
Information about the properties is organized as follows:

* xref:required-debezium-oracle-connector-configuration-properties[Required {prodname} Oracle connector configuration properties]
* xref:debezium-oracle-connector-database-history-configuration-properties[Database schema history connector configuration properties] that control how {prodname} processes events that it reads from the database schema history topic.
** xref:oracle-pass-through-database-history-properties-for-configuring-producer-and-consumer-clients[Pass-through database schema history properties]
* xref:debezium-oracle-connector-pass-through-database-driver-configuration-properties[Pass-through database driver properties] that control the behavior of the database driver.

[id="required-debezium-{context}-connector-configuration-properties"]
=== Required {prodname} Oracle connector configuration properties
The following configuration properties are _required_ unless a default value is available.

[cols="30%a,25%a,45%a"]
|===
|Property
|Default
|Description

|[[oracle-property-name]]<<oracle-property-name, `+name+`>>
|No default
|Unique name for the connector. Attempting to register again with the same name will fail. (This property is required by all Kafka Connect connectors.)

|[[oracle-property-connector-class]]<<oracle-property-connector-class, `+connector.class+`>>
|No default
|The name of the Java class for the connector. Always use a value of `io.debezium.connector.oracle.OracleConnector` for the Oracle connector.

|[[oracle-property-converters]]<<oracle-property-converters, `converters`>>
|No default
|Enumerates a comma-separated list of the symbolic names of the {link-prefix}:{link-custom-converters}#custom-converters[custom converter] instances that the connector can use. +
For example, `boolean`. +
This property is required to enable the connector to use a custom converter.

For each converter that you configure for a connector, you must also add a `.type` property, which specifies the fully-qualifed name of the class that implements the converter interface.
The `.type` property uses the following format: +

`_<converterSymbolicName>_.type` +

For example, +

 boolean.type: io.debezium.connector.oracle.converters.NumberOneToBooleanConverter

If you want to further control the behavior of a configured converter, you can add one or more configuration parameters to pass values to the converter.
To associate any additional configuration parameters with a converter, prefix the parameter names with the symbolic name of the converter. +
 +
For example, to define a `selector` parameter that specifies the subset of columns that the `boolean` converter processes, add the following property: +

 boolean.selector: .*MYTABLE.FLAG,.*.IS_ARCHIVED

|[[oracle-property-tasks-max]]<<oracle-property-tasks-max, `+tasks.max+`>>
|`1`
|The maximum number of tasks to create for this connector. The Oracle connector always uses a single task and therefore does not use this value, so the default is always acceptable.

|[[oracle-property-database-hostname]]<<oracle-property-database-hostname, `+database.hostname+`>>
|No default
|IP address or hostname of the Oracle database server.

|[[oracle-property-database-port]]<<oracle-property-database-port, `+database.port+`>>
|No default
|Integer port number of the Oracle database server.

|[[oracle-property-database-user]]<<oracle-property-database-user, `+database.user+`>>
|No default
|Name of the Oracle user account that the connector uses to connect to the Oracle database server.

|[[oracle-property-database-password]]<<oracle-property-database-password, `+database.password+`>>
|No default
|Password to use when connecting to the Oracle database server.

|[[oracle-property-database-dbname]]<<oracle-property-database-dbname, `+database.dbname+`>>
|No default
|Name of the database to connect to. Must be the CDB name when working with the CDB + PDB model.

|[[oracle-property-database-url]]<<oracle-property-database-url, `+database.url+`>>
|No default
|Specifies the raw database JDBC URL. Use this property to provide flexibility in defining that database connection.
Valid values include raw TNS names and RAC connection strings.
ifdef::product[]
[NOTE]
Using the connector in a RAC environment is a Technology Preview feature.
endif::product[]

|[[oracle-property-database-pdb-name]]<<oracle-property-database-pdb-name, `+database.pdb.name+`>>
|No default
|Name of the Oracle pluggable database to connect to. Use this property with container database (CDB) installations only.

|[[oracle-property-topic-prefix]]<<oracle-property-topic-prefix, `+topic.prefix+`>>
|No default
|Topic prefix that provides a namespace for the Oracle database server from which the connector captures changes.
The value that you set is used as a prefix for all Kafka topic names that the connector emits.
Specify a topic prefix that is unique among all connectors in your {prodname} environment.
The following characters are valid: alphanumeric characters, hyphens, dots, and underscores. +
 +
[WARNING]
====
Do not change the value of this property.
If you change the name value, after a restart, instead of continuing to emit events to the original topics, the connector emits subsequent events to topics whose names are based on the new value.
The connector is also unable to recover its database schema history topic.
====

|[[oracle-property-database-connection-adapter]]<<oracle-property-database-connection-adapter, `+database.connection.adapter+`>>
|`logminer`
|The adapter implementation that the connector uses when it streams database changes.
You can set the following values:
`logminer`(default):: The connector uses the native Oracle LogMiner API.
ifdef::community[]
`xstream`:: The connector uses the Oracle XStreams API.
endif::community[]
|[[oracle-property-snapshot-mode]]<<oracle-property-snapshot-mode, `+snapshot.mode+`>>
|_initial_
|Specifies the mode that the connector uses to take snapshots of a captured table.
You can set the following values:

`initial`:: The snapshot includes the structure and data of the captured tables.
Specify this value to populate topics with a complete representation of the data from the captured tables.

`initial_only`:: The snapshot includes the structure and data of the captured tables.
The connector performs an initial snapshot and then stops, without processing any subsequent changes.

`schema_only`:: The snapshot includes only the structure of captured tables.
Specify this value if you want the connector to capture data only for changes that occur after the snapshot.

`schema_only_recovery`:: This is a recovery setting for a connector that has already been capturing changes.
When you restart the connector, this setting enables recovery of a corrupted or lost database schema history topic.
You might set it periodically to "clean up" a database schema history topic that has been growing unexpectedly.
Database schema history topics require infinite retention.
Note this mode is only safe to be used when it is guaranteed that no schema changes happened since the point in time the connector was shut down before and the point in time the snapshot is taken.

After the snapshot is complete, the connector continues to read change events from the database's redo logs except when `snapshot.mode` is configured as `initial_only`.

For more information, see the xref:oracle-connector-snapshot-mode-options[table of `snapshot.mode` options].

|[[oracle-property-snapshot-locking-mode]]<<oracle-property-snapshot-locking-mode, `+snapshot.locking.mode+`>>
|_shared_
a|Controls whether and for how long the connector holds a table lock. Table locks prevent certain types of changes table operations from occurring while the connector performs a snapshot.
You can set the following values:

`shared`:: Enables concurrent access to the table, but prevents any session from acquiring an exclusive table lock.
  The connector acquires a `ROW SHARE` level lock while it captures table schema.

`none`:: Prevents the connector from acquiring any table locks during the snapshot.
  Use this setting only if no schema changes might occur during the creation of the snapshot.

|[[oracle-property-snapshot-include-collection-list]]<<oracle-property-snapshot-include-collection-list, `+snapshot.include.collection.list+`>>
| All tables specified in `table.include.list`
|An optional, comma-separated list of regular expressions that match the fully-qualified names (`_<schemaName>_._<tableName>_`) of the tables to include in a snapshot.
ifdef::product[]
Only POSIX regular expressions are valid.
endif::product[]
ifdef::community[]
In environments that use the LogMiner implementation, you must use POSIX regular expressions only.
endif::community[]
The specified items must be named in the connector's xref:{context}-property-table-include-list[`table.include.list`] property.
This property takes effect only if the connector's xref:oracle-property-snapshot-mode[`snapshot.mode`] property is set to a value other than `never`. +
This property does not affect the behavior of incremental snapshots. +

To match the name of a table, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the table; it does not match substrings that might be present in a table name.

|[[oracle-property-snapshot-select-statement-overrides]]<<oracle-property-snapshot-select-statement-overrides, `+snapshot.select.statement.overrides+`>>
|No default
|Specifies the table rows to include in a snapshot.
Use the property if you want a snapshot to include only a subset of the rows in a table.
This property affects snapshots only.
It does not apply to events that the connector reads from the log.

The property contains a comma-separated list of fully-qualified table names in the form `_<schemaName>.<tableName>_`. For example, +
 +
`+"snapshot.select.statement.overrides": "inventory.products,customers.orders"+` +
 +
For each table in the list, add a further configuration property that specifies the `SELECT` statement for the connector to run on the table when it takes a snapshot.
The specified `SELECT` statement determines the subset of table rows to include in the snapshot.
Use the following format to specify the name of this `SELECT` statement property: +
 +
`snapshot.select.statement.overrides._<schemaName>_._<tableName>_` +
 +
For example,
`snapshot.select.statement.overrides.customers.orders` +
 +
Example:

From a `customers.orders` table that includes the soft-delete column, `delete_flag`, add the following properties if you want a snapshot to include only those records that are not soft-deleted:

----
"snapshot.select.statement.overrides": "customer.orders",
"snapshot.select.statement.overrides.customer.orders": "SELECT * FROM [customers].[orders] WHERE delete_flag = 0 ORDER BY id DESC"
----

In the resulting snapshot, the connector includes only the records for which `delete_flag = 0`.

|[[oracle-property-schema-include-list]]<<oracle-property-schema-include-list, `+schema.include.list+`>>
|No default
|An optional, comma-separated list of regular expressions that match names of schemas for which you *want* to capture changes.
ifdef::product[]
Only POSIX regular expressions are valid.
endif::product[]
ifdef::community[]
In environments that use the LogMiner implementation, you must use POSIX regular expressions only.
endif::community[]
Any schema name not included in `schema.include.list` is excluded from having its changes captured.
By default, all non-system schemas have their changes captured. +

To match the name of a schema, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the schema; it does not match substrings that might be present in a schema name. +
If you include this property in the configuration, do not also set the `schema.exclude.list` property.

|[[oracle-property-include-schema-comments]]<<oracle-property-include-schema-comments, `+include.schema.comments+`>>
|`false`
|Boolean value that specifies whether the connector should parse and publish table and column comments on metadata objects. Enabling this option will bring the implications on memory usage. The number and size of logical schema objects is what largely impacts how much memory is consumed by the Debezium connectors, and adding potentially large string data to each of them can potentially be quite expensive.

|[[oracle-property-schema-exclude-list]]<<oracle-property-schema-exclude-list, `+schema.exclude.list+`>>
|No default
|An optional, comma-separated list of regular expressions that match names of schemas for which you *do not* want to capture changes.
ifdef::product[]
Only POSIX regular expressions are valid.
endif::product[]
ifdef::community[]
In environments that use the LogMiner implementation, you must use POSIX regular expressions only. +
endif::community[]
Any schema whose name is not included in `schema.exclude.list` has its changes captured, with the exception of system schemas. +

To match the name of a schema, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the schema; it does not match substrings that might be present in a schema name. +
If you include this property in the configuration, do not set the`schema.include.list` property.

|[[oracle-property-table-include-list]]<<oracle-property-table-include-list, `+table.include.list+`>>
|No default
|An optional comma-separated list of regular expressions that match fully-qualified table identifiers for tables to be captured.
ifdef::product[]
Only POSIX regular expressions are valid.
endif::product[]
ifdef::community[]
If you use the LogMiner implementation, use only POSIX regular expressions with this property.
endif::community[]
When this property is set, the connector captures changes only from the specified tables.
Each table identifier uses the following format: +
 +
`__<schema_name>.<table_name>__` +
 +
By default, the connector monitors every non-system table in each captured database. +

To match the name of a table, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the table; it does not match substrings that might be present in a table name. +
If you include this property in the configuration, do not also set the `table.exclude.list` property.

|[[oracle-property-table-exclude-list]]<<oracle-property-table-exclude-list, `+table.exclude.list+`>>
|No default
|An optional comma-separated list of regular expressions that match fully-qualified table identifiers for tables to be excluded from monitoring.
ifdef::product[]
Only POSIX regular expressions are valid.
endif::product[]
ifdef::community[]
If you use the LogMiner implementation, use only POSIX regular expressions with this property.
endif::community[]
The connector captures change events from any table that is not specified in the exclude list.
Specify the identifier for each table using the following format: +
 +
`_<schemaName>.<tableName>_`.

To match the name of a table, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the table; it does not match substrings that might be present in a table name. +
If you include this property in the configuration, do not also set the `table.include.list` property.

|[[oracle-property-column-include-list]]<<oracle-property-column-include-list, `+column.include.list+`>>
|No default
|An optional, comma-separated list of regular expressions that match the fully-qualified names of columns that want to include in the change event message values.
ifdef::product[]
Only POSIX regular expressions are valid.
endif::product[]
ifdef::community[]
In environments that use the LogMiner implementation, you must use POSIX regular expressions only.
endif::community[]
Fully-qualified names for columns use the following format: +
 +
`_<Schema_name>.<table_name>.<column_name>_` +
 +
The primary key column is always included in an event's key, even if you do not use this property to explicitly include its value. +

To match the name of a column, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the column it does not match substrings that might be present in a column name. +
If you include this property in the configuration, do not also set the `column.exclude.list` property.

|[[oracle-property-column-exclude-list]]<<oracle-property-column-exclude-list, `+column.exclude.list+`>>
|No default
|An optional, comma-separated list of regular expressions that match the fully-qualified names of columns that you want to exclude from change event message values.
ifdef::product[]
Only POSIX regular expressions are valid.
endif::product[]
ifdef::community[]
In environments that use the LogMiner implementation, you must use POSIX regular expressions only.
endif::community[]
Fully-qualified column names use the following format: +
 +
`_<schema_name>.<table_name>.<column_name>_` +
 +
The primary key column is always included in an event's key, even if you use this property to explicitly exclude its value. +

To match the name of a column, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the column it does not match substrings that might be present in a column name. +
If you include this property in the configuration, do not set the `column.include.list` property.

|[[oracle-property-column-mask-hash]]<<oracle-property-column-mask-hash, `column.mask.hash._hashAlgorithm_.with.salt._salt_`>>;
[[oracle-property-column-mask-hash-v2]]<<oracle-property-column-mask-hash-v2, `column.mask.hash.v2._hashAlgorithm_.with.salt._salt_`>>
|_n/a_
|An optional, comma-separated list of regular expressions that match the fully-qualified names of character-based columns.
Fully-qualified names for columns are of the form `_<schemaName>_._<tableName>_._<columnName>_`. +
To match the name of a column {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the column; the expression does not match substrings that might be present in a column name. +
In the resulting change event record, the values for the specified columns are replaced with pseudonyms. +

A pseudonym consists of the hashed value that results from applying the specified _hashAlgorithm_ and _salt_.
Based on the hash function that is used, referential integrity is maintained, while column values are replaced with pseudonyms.
Supported hash functions are described in the {link-java7-standard-names}[MessageDigest section] of the Java Cryptography Architecture Standard Algorithm Name Documentation. +
 +
In the following example, `CzQMA0cB5K` is a randomly selected salt. +

----
column.mask.hash.SHA-256.with.salt.CzQMA0cB5K = inventory.orders.customerName, inventory.shipment.customerName
----

If necessary, the pseudonym is automatically shortened to the length of the column.
The connector configuration can include multiple properties that specify different hash algorithms and salts. +
 +
Depending on the _hashAlgorithm_ used, the _salt_ selected, and the actual data set, the resulting data set might not be completely masked. +
 +
Hashing strategy version 2 should be used to ensure fidelity if the value is being hashed in different places or systems.

|[[oracle-property-binary-handling-mode]]<<oracle-property-binary-handling-mode, `+binary.handling.mode+`>>
|bytes
|Specifies how binary (`blob`) columns should be represented in change events, including: `bytes` represents binary data as byte array (default), `base64` represents binary data as base64-encoded String, `base64-url-safe` represents binary data as base64-url-safe-encoded String, `hex` represents binary data as hex-encoded (base16) String


|[[oracle-property-schema-name-adjustment-mode]]<<oracle-property-schema-name-adjustment-mode,`+schema.name.adjustment.mode+`>>
|none
|Specifies how schema names should be adjusted for compatibility with the message converter used by the connector. Possible settings:  +

* `none` does not apply any adjustment. +
* `avro` replaces the characters that cannot be used in the Avro type name with underscore. +

|[[oracle-property-decimal-handling-mode]]<<oracle-property-decimal-handling-mode, `+decimal.handling.mode+`>>
|`precise`
| Specifies how the connector should handle floating point values for `NUMBER`, `DECIMAL` and `NUMERIC` columns.
You can set one of the following options:

`precise` (default):: Represents values precisely by using `java.math.BigDecimal` values represented in change events in a binary form.
`double`:: Represents values by using `double` values.
  Using `double` values is easier, but can result in a loss of precision.
`string`:: Encodes values as formatted strings.
  Using the `string` option is easier to consume, but results in a loss of semantic information about the real type.
  For more information, see <<oracle-numeric-types>>.

|[[oracle-property-interval-handling-mode]]<<oracle-property-interval-handling-mode, `+interval.handling.mode+`>>
|`numeric`
| Specifies how the connector should handle values for `interval` columns: +
 +
`numeric` represents intervals using approximate number of microseconds. +
 +
`string` represents intervals exactly by using the string pattern representation `P<years>Y<months>M<days>DT<hours>H<minutes>M<seconds>S`. For example: `P1Y2M3DT4H5M6.78S`.

|[[oracle-property-event-processing-failure-handling-mode]]<<oracle-property-event-processing-failure-handling-mode, `+event.processing.failure.handling.mode+`>>
|`fail`
| Specifies how the connector should react to exceptions during processing of events.
You can set one of the following options:

`fail`:: Propagates the exception (indicating the offset of the problematic event), causing the connector to stop.
`warn`:: Causes the problematic event to be skipped. The offset of the problematic event is then logged.
`skip`:: Causes the problematic event to be skipped.

|[[oracle-property-max-batch-size]]<<oracle-property-max-batch-size, `+max.batch.size+`>>
|`2048`
|A positive integer value that specifies the maximum size of each batch of events to process during each iteration of this connector.

|[[oracle-property-max-queue-size]]<<oracle-property-max-queue-size, `+max.queue.size+`>>
|`8192`
|Positive integer value that specifies the maximum number of records that the blocking queue can hold.
When {prodname} reads events streamed from the database, it places the events in the blocking queue before it writes them to Kafka.
The blocking queue can provide backpressure for reading change events from the database
in cases where the connector ingests messages faster than it can write them to Kafka, or when Kafka becomes unavailable.
Events that are held in the queue are disregarded when the connector periodically records offsets.
Always set the value of `max.queue.size` to be larger than the value of xref:{context}-property-max-batch-size[`max.batch.size`].

|[[oracle-property-max-queue-size-in-bytes]]<<oracle-property-max-queue-size-in-bytes, `+max.queue.size.in.bytes+`>>
|`0` (disabled)
|A long integer value that specifies the maximum volume of the blocking queue in bytes.
By default, volume limits are not specified for the blocking queue.
To specify the number of bytes that the queue can consume, set this property to a positive long value. +
If xref:oracle-property-max-queue-size[`max.queue.size`] is also set, writing to the queue is blocked when the size of the queue reaches the limit specified by either property.
For example, if you set `max.queue.size=1000`, and `max.queue.size.in.bytes=5000`, writing to the queue is blocked after the queue contains 1000 records, or after the volume of the records in the queue reaches 5000 bytes.

|[[oracle-property-poll-interval-ms]]<<oracle-property-poll-interval-ms, `+poll.interval.ms+`>>
|`500` (0.5 second)
|Positive integer value that specifies the number of milliseconds the connector should wait during each iteration for new change events to appear.

|[[oracle-property-tombstones-on-delete]]<<oracle-property-tombstones-on-delete, `+tombstones.on.delete+`>>
|`true`
|Controls whether a _delete_ event is followed by a tombstone event.
The following values are possible:

`true`:: For each delete operation, the connector emits a _delete_ event and a subsequent tombstone event.
`false`:: For each delete operation, the connector emits only a _delete_ event.

After a source record is deleted, a tombstone event (the default behavior) enables Kafka to completely delete all events that share the key of the deleted row in topics that have {link-kafka-docs}/#compaction[log compaction] enabled.

|[[oracle-property-message-key-columns]]<<oracle-property-message-key-columns, `+message.key.columns+`>>
|No default
|A list of expressions that specify the columns that the connector uses to form custom message keys for change event records that it publishes to the Kafka topics for specified tables.

By default, {prodname} uses the primary key column of a table as the message key for records that it emits.
In place of the default, or to specify a key for tables that lack a primary key, you can configure custom message keys based on one or more columns. +
To establish a custom message key for a table, list the table, followed by the columns to use as the message key.
Each list entry takes the following format: +
 +
   `_<fullyQualifiedTableName>_`:``_<keyColumn>_``,``_<keyColumn>_`` +
 +
To base a table key on multiple column names, insert commas between the column names. +
Each fully-qualified table name is a regular expression in the following format: +
 +
`_<schemaName>_._<tableName>_` +
 +
The property can include entries for multiple tables.
Use a semicolon to separate table entries in the list. +
 The following example sets the message key for the tables `inventory.customers` and `purchase.orders`: +
 +
`inventory.customers:pk1,pk2;(.*).purchaseorders:pk3,pk4` +
 +
For the table `inventory.customer`, the columns `pk1` and `pk2` are specified as the message key.
For the `purchaseorders` tables in any schema, the columns `pk3` and `pk4` server as the message key. +
There is no limit to the number of columns that you use to create custom message keys.
However, it's best to use the minimum number that are required to specify a unique key.

|[[oracle-property-column-truncate-to-length-chars]]<<oracle-property-column-truncate-to-length-chars, `column.truncate.to._length_.chars`>>
|No default
|An optional, comma-separated list of regular expressions that match the fully-qualified names of character-based columns.
Set this property if you want the connector to mask the values for a set of columns, for example, if they contain sensitive data.
Set `_length_` to a positive integer to replace data in the specified columns with the number of asterisk (`*`) characters specified by the _length_ in the property name.
Set _length_ to `0` (zero) to replace data in the specified columns with an empty string.

The fully-qualified name of a column observes the following format: `_<schemaName>_._<tableName>_._<columnName>_`.
To match the name of a column, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the column; the expression does not match substrings that might be present in a column name.

You can specify multiple properties with different lengths in a single configuration.

|[[oracle-property-column-mask-with-length-chars]]<<oracle-property-column-mask-with-length-chars, `column.mask.with._length_.chars`>>
|No default
|An optional comma-separated list of regular expressions for masking column names in change event messages by replacing characters with asterisks (`*`). +
Specify the number of characters to replace in the name of the property, for example, `column.mask.with.8.chars`. +
Specify length as a positive integer or zero.
Then add regular expressions to the list for each character-based column name where you want to apply a mask. +
Use the following format to specify fully-qualified column names: `_<schemaName>_._<tableName>_._<columnName>_`. +
 +
The connector configuration can include multiple properties that specify different lengths.

|[[oracle-property-column-propagate-source-type]]<<oracle-property-column-propagate-source-type, `+column.propagate.source.type+`>>
|No default
|An optional, comma-separated list of regular expressions that match the fully-qualified names of columns for which you want the connector to emit extra parameters that represent column metadata.
When this property is set, the connector adds the following fields to the schema of event records:

* `pass:[_]pass:[_]debezium.source.column.type` +
* `pass:[_]pass:[_]debezium.source.column.length` +
* `pass:[_]pass:[_]debezium.source.column.scale` +

These parameters propagate a column's original type name and length (for variable-width types), respectively. +
Enabling the connector to emit this extra data can assist in properly sizing specific numeric or character-based columns in sink databases.

The fully-qualified name of a column observes one of the following formats: `_<tableName>_._<columnName>_`, or `_<schemaName>_._<tableName>_._<columnName>_`. +
To match the name of a column, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the column; the expression does not match substrings that might be present in a column name.

|[[oracle-property-datatype-propagate-source-type]]<<oracle-property-datatype-propagate-source-type, `+datatype.propagate.source.type+`>>
|No default
|An optional, comma-separated list of regular expressions that specify the fully-qualified names of data types that are defined for columns in a database.
When this property is set, for columns with matching data types, the connector emits event records that include the following extra fields in their schema:

* `pass:[_]pass:[_]debezium.source.column.type` +
* `pass:[_]pass:[_]debezium.source.column.length` +
* `pass:[_]pass:[_]debezium.source.column.scale` +

These parameters propagate a column's original type name and length (for variable-width types), respectively. +
Enabling the connector to emit this extra data can assist in properly sizing specific numeric or character-based columns in sink databases.

The fully-qualified name of a column observes one of the following formats: `_<tableName>_._<typeName>_`, or `_<schemaName>_._<tableName>_._<typeName>_`.  +
To match the name of a data type, {prodname} applies the regular expression that you specify as an _anchored_ regular expression.
That is, the specified expression is matched against the entire name string of the data type; the expression does not match substrings that might be present in a type name.

For the list of Oracle-specific data type names, see the xref:oracle-data-type-mappings[Oracle data type mappings].

|[[oracle-property-heartbeat-interval-ms]]<<oracle-property-heartbeat-interval-ms, `+heartbeat.interval.ms+`>>
|`0`
|Specifies, in milliseconds, how frequently the connector sends messages to a heartbeat topic. +
Use this property to determine whether the connector continues to receive change events from the source database. +
It can also be useful to set the property in situations where no change events occur in captured tables for an extended period. +
In such a case, although the connector continues to read the redo log, it emits no change event messages, so that the offset in the Kafka topic remains unchanged.
Because the connector does not flush the latest system change number (SCN) that it read from the database, the database might retain the redo log files for longer than necessary.
If the connector restarts, the extended retention period could result in the connector redundantly sending some change events. +
The default value of `0` prevents the connector from sending any heartbeat messages.

|[[oracle-property-heartbeat-action-query]]<<oracle-property-heartbeat-action-query, `+heartbeat.action.query+`>>
|No default
|Specifies a query that the connector executes on the source database when the connector sends a heartbeat message. +
 +
For example: +
 +
`INSERT INTO test_heartbeat_table (text) VALUES ('test_heartbeat')` +
 +
The connector runs the query after it emits a xref:oracle-property-heartbeat-interval-ms[heartbeat message].

Set this property and create a heartbeat table to receive the heartbeat messages to resolve situations in which xref:low-change-frequency-offset-management[{prodname} fails to synchronize offsets on low-traffic databases that are on the same host as a high-traffic database].
After the connector inserts records into the configured table, it is able to receive changes from the low-traffic database and acknowledge SCN changes in the database, so that offsets can be synchronized with the broker.

|[[oracle-property-snapshot-delay-ms]]<<oracle-property-snapshot-delay-ms, `+snapshot.delay.ms+`>>
|No default
|Specifies an interval in milliseconds that the connector waits after it starts before it takes a snapshot. +
Use this property to prevent snapshot interruptions when you start multiple connectors in a cluster, which might cause re-balancing of connectors.

|[[oracle-property-snapshot-fetch-size]]<<oracle-property-snapshot-fetch-size, `+snapshot.fetch.size+`>>
|`2000`
|Specifies the maximum number of rows that should be read in one go from each table while taking a snapshot.
The connector reads table contents in multiple batches of the specified size.

|[[oracle-property-query-fetch-size]]<<oracle-property-query-fetch-size, `+query.fetch.size+`>>
|No default
|Specifies the number of rows that will be fetched for each database round-trip of a given query.
Defaults to the JDBC driver's default fetch size.

|[[oracle-property-sanitize-field-names]]<<oracle-property-sanitize-field-names, `+sanitize.field.names+`>>
|`true` when the connector configuration explicitly specifies the `key.converter` or `value.converter` parameters to use Avro, otherwise defaults to `false`.
|Specifies whether field names are normalized to comply with Avro naming requirements.
For more information, see xref:{link-avro-serialization}#avro-naming[Avro naming].

|[[oracle-property-provide-transaction-metadata]]<<oracle-property-provide-transaction-metadata, `+provide.transaction.metadata+`>>
|`false`
|Set the property to `true` if you want {prodname} to generate events with transaction boundaries and enriches data events envelope with transaction metadata.

See xref:{link-oracle-connector}#oracle-transaction-metadata[Transaction Metadata] for additional details.

|[[oracle-property-log-mining-strategy]]<<oracle-property-log-mining-strategy, `+log.mining.strategy+`>>
|`redo_log_catalog`
|Specifies the mining strategy that controls how Oracle LogMiner builds and uses a given data dictionary for resolving table and column ids to names. +
 +
`redo_log_catalog`:: Writes the data dictionary to the online redo logs causing more archive logs to be generated over time.
This also enables tracking DDL changes against captured tables, so if the schema changes frequently this is the ideal choice. +
 +
`online_catalog`:: Uses the database's current data dictionary to resolve object ids and does not write any extra information to the online redo logs.
This allows LogMiner to mine substantially faster but at the expense that DDL changes cannot be tracked.
If the captured table(s) schema changes infrequently or never, this is the ideal choice.

|[[oracle-property-log-mining-buffer-type]]<<oracle-property-log-mining-buffer-type, `+log.mining.buffer.type+`>>
|`memory`
|The buffer type controls how the connector manages buffering transaction data. +
 +
`memory` - Uses the JVM process' heap to buffer all transaction data.
Choose this option if you don't expect the connector to process a high number of long-running or large transactions.
When this option is active, the buffer state is not persisted across restarts.
Following a restart, recreate the buffer from the SCN value of the current offset. +
ifdef::community[]
 +
`infinispan_embedded` - This option uses an embedded Infinispan cache to buffer transaction data and persist it to disk.
+
`infinispan_remote` - This option uses a remote Infinispan cluster to buffer transaction data and persist it to disk.


|[[oracle-property-log-mining-buffer-transaction-events-threshold]]<<oracle-property-log-mining-buffer-transaction-events-threshold, `+log.mining.buffer.transaction.events.threshold+`>>
|`0`
|The maximum number of events a transaction is capable of having in the transaction buffer.
Transactions with event counts that exceed this threshold not be emitted and will be abandoned.
The default behavior is there is no transaction event threshold.

|[[oracle-property-log-mining-buffer-infinispan-cache-transactions]]<<oracle-property-log-mining-buffer-infinispan-cache-transactions, `+log.mining.buffer.infinispan.cache.transactions+`>>
|No default
|The XML configuration for the Infinispan transaction cache.
For more information, see xref:oracle-event-buffering-infinispan[Infinispan event buffering].

|[[oracle-property-log-mining-buffer-infinispan-cache-events]]<<oracle-property-log-mining-buffer-infinispan-cache-events, `+log.mining.buffer.infinispan.cache.events+`>>
|No default
|The XML configuration for the Infinispan events cache.
For more information, see xref:oracle-event-buffering-infinispan[Infinispan event buffering].

|[[oracle-property-log-mining-buffer-infinispan-cache-processed-transactions]]<<oracle-property-log-mining-buffer-infinispan-cache-processed-transactions, `+log.mining.buffer.infinispan.cache.processed_transactions+`>>
|No default
|The XML configuration for the Infinispan processed transactions cache.
For more information, see xref:oracle-event-buffering-infinispan[Infinispan event buffering].

|[[oracle-property-log-mining-buffer-infinispan-cache-schema-changes]]<<oracle-property-log-mining-buffer-infinispan-cache-schema-changes, `+log.mining.buffer.infinispan.cache.schema_changes+`>>
|No default
|The XML configuration for the Infinispan schema changes cache.

|[[oracle-property-log-mining-buffer-drop-on-stop]]<<oracle-property-log-mining-buffer-drop-on-stop, `+log.mining.buffer.drop.on.stop+`>>
|`false`
|Specifies whether the buffer state is deleted after the connector stops in a graceful, expected way. +
 +
This setting only impacts buffer implementations that persist state across restarts, such as `infinispan`. +
The default behavior is that the buffer state is always retained between restarts. +
 +
Set to `true` only in testing or development environments.
endif::community[]

|[[oracle-property-log-mining-session-max-ms]]<<oracle-property-log-mining-session-max-ms, `+log.mining.session.max.xs+`>>
|`0`
|The maximum number of milliseconds that a LogMiner session can be active before a new session is used. +
 +
For low volume systems, a LogMiner session may consume too much PGA memory when the same session is used for a long period of time.
The default behavior is to only use a new LogMiner session when a log switch is detected.
By setting this value to something greater than `0`, this specifies the maximum number of milliseconds a LogMiner session can be active before it gets stopped and started to deallocate and reallocate PGA memory.

|[[oracle-property-log-mining-batch-size-min]]<<oracle-property-log-mining-batch-size-min, `+log.mining.batch.size.min+`>>
|`1000`
|The minimum SCN interval size that this connector attempts to read from redo/archive logs. Active batch size is also increased/decreased by this amount for tuning connector throughput when needed.

|[[oracle-property-log-mining-batch-size-max]]<<oracle-property-log-mining-batch-size-max, `+log.mining.batch.size.max+`>>
|`100000`
|The maximum SCN interval size that this connector uses when reading from redo/archive logs.

|[[oracle-property-log-mining-batch-size-default]]<<oracle-property-log-mining-batch-size-default, `+log.mining.batch.size.default+`>>
|`20000`
|The starting SCN interval size that the connector uses for reading data from redo/archive logs.

|[[oracle-property-log-mining-sleep-time-min-ms]]<<oracle-property-log-mining-sleep-time-min-ms, `+log.mining.sleep.time.min.ms+`>>
|`0`
|The minimum amount of time that the connector sleeps after reading data from redo/archive logs and before starting reading data again. Value is in milliseconds.

|[[oracle-property-log-mining-sleep-time-max-ms]]<<oracle-property-log-mining-sleep-time-max-ms, `+log.mining.sleep.time.max.ms+`>>
|`3000`
|The maximum amount of time that the connector ill sleeps after reading data from redo/archive logs and before starting reading data again. Value is in milliseconds.

|[[oracle-property-log-mining-sleep-time-default-ms]]<<oracle-property-log-mining-sleep-time-default-ms, `+log.mining.sleep.time.default.ms+`>>
|`1000`
|The starting amount of time that the connector sleeps after reading data from redo/archive logs and before starting reading data again. Value is in milliseconds.

|[[oracle-property-log-mining-sleep-time-increment-ms]]<<oracle-property-log-mining-sleep-time-increment-ms, `+log.mining.sleep.time.increment.ms+`>>
|`200`
|The maximum amount of time up or down that the connector uses to tune the optimal sleep time when reading data from logminer. Value is in milliseconds.

|[[oracle-property-log-mining-archive-log-hours]]<<oracle-property-log-mining-archive-log-hours, `+log.mining.archive.log.hours+`>>
|`0`
|The number of hours in the past from SYSDATE to mine archive logs.
When the default setting (`0`) is used, the connector mines all archive logs.

|[[oracle-property-log-mining-archive-log-only-mode]]<<oracle-property-log-mining-archive-log-only-mode, `+log.mining.archive.log.only.mode+`>>
|`false`
|Controls whether or not the connector mines changes from just archive logs or a combination of the online redo logs and archive logs (the default). +
 +
Redo logs use a circular buffer that can be archived at any point.
In environments where online redo logs are archived frequently, this can lead to LogMiner session failures.
In contrast to redo logs, archive logs are guaranteed to be reliable.
Set this option to `true` to force the connector to mine archive logs only.
After you set the connector to mine only the archive logs, the latency between an operation being committed and the connector emitting an associated change event might increase.
The degree of latency depends on how frequently the database is configured to archive online redo logs.

|[[oracle-property-log-mining-archive-log-only-scn-poll-interval-ms]]<<oracle-property-log-mining-archive-log-only-scn-poll-interval-ms, `+log.mining.archive.log.only.scn.poll.interval.ms+`>>
|`10000`
|The number of milliseconds the connector will sleep in between polling to determine if the starting system change number is in the archive logs.
If `log.mining.archive.log.only.mode` is not enabled, this setting is not used.

|[[oracle-property-log-mining-transaction-retention-hours]]<<oracle-property-log-mining-transaction-retention-hours, `log.mining.transaction.retention.hours`>>
|`0`
|Positive integer value that specifies the number of hours to retain long running transactions between redo log switches.
When set to `0`, transactions are retained until a commit or rollback is detected.

The LogMiner adapter maintains an in-memory buffer of all running transactions.
Because all of the DML operations that are part of a transaction are buffered until a commit or rollback is detected,
long-running transactions should be avoided in order to not overflow that buffer.
Any transaction that exceeds this configured value is discarded entirely, and the connector does not emit any messages for the operations that were part of the transaction.
ifdef::community[]
While this option allows the behavior to be configured on a case-by-case basis,
we have plans to enhance this behavior in a future release by means of adding a scalable transaction buffer, (see xref:{jira-url}/browse/DBZ-3123[DBZ-3123]).
endif::community[]
|[[oracle-property-log-mining-archive-destination-name]]<<oracle-property-log-mining-archive-destination-name, `+log.mining.archive.destination.name+`>>
|No default
|Specifies the configured Oracle archive destination to use when mining archive logs with LogMiner. +
 +
The default behavior automatically selects the first valid, local configured destination.
However, you can use a specific destination can be used by providing the destination name, for example, `LOG_ARCHIVE_DEST_5`.

|[[oracle-property-log-mining-username-exclude-list]]<<oracle-property-log-mining-username-exclude-list, `+log.mining.username.exclude.list+`>>
|No default
|List of database users to exclude from the LogMiner query.
It can be useful to set this property if you want the capturing process to always exclude the changes that specific users make.

|[[oracle-property-log-mining-scn-gap-detection-gap-size-min]]<<oracle-property-log-mining-scn-gap-detection-gap-size-min, `+log.mining.scn.gap.detection.gap.size.min+`>>
|`1000000`
|Specifies a value that the connector compares to the difference between the current and previous SCN values to determine whether an SCN gap exists.
If the difference between the SCN values is greater than the specified value, and the time difference is smaller than xref:oracle-property-log-mining-scn-gap-detection-time-interval-max-ms[`log.mining.scn.gap.detection.time.interval.max.ms`] then an SCN gap is detected, and the connector uses a mining window larger than the configured maximum batch.

|[[oracle-property-log-mining-scn-gap-detection-time-interval-max-ms]]<<oracle-property-log-mining-scn-gap-detection-time-interval-max-ms, `+log.mining.scn.gap.detection.time.interval.max.ms+`>>
|`20000`
|Specifies a value,  in milliseconds, that the connector compares to the difference between the current and previous SCN timestamps  to determine whether an SCN gap exists.
If the difference between the timestamps is less than the specified value, and the SCN delta is greater than xref:oracle-property-log-mining-scn-gap-detection-gap-size-min[`log.mining.scn.gap.detection.gap.size.min`], then an SCN gap is detected and the connector uses a mining window larger than the configured maximum batch.

|[[oracle-property-lob-enabled]]<<oracle-property-lob-enabled, `+lob.enabled+`>>
|`false`
|Controls whether or not large object (CLOB or BLOB) column values are emitted in change events. +
 +
By default, change events have large object columns, but the columns contain no values.
There is a certain amount of overhead in processing and managing large object column types and payloads.
To capture large object values and serialized them in change events, set this option to `true`.

ifdef::product[]
NOTE: Use of large object data types is a Technology Preview feature.
endif::product[]

|[[oracle-property-unavailable-value-placeholder]]<<oracle-property-unavailable-value-placeholder, `+unavailable.value.placeholder+`>>
|`__debezium_unavailable_value`
|Specifies the constant that the connector provides to indicate that the original value is unchanged and not provided by the database.

|[[oracle-property-rac-nodes]]<<oracle-property-rac-nodes, `+rac.nodes+`>>
|No default
|A comma-separated list of Oracle Real Application Clusters (RAC) node host names or addresses.
This field is required to enable compatibility with an Oracle RAC deployment.
ifdef::product[]
[NOTE]
Using the connector in a RAC environment is a Technology Preview feature.
endif::product[]

Specify the list of RAC nodes by using one of the following methods:

* Specify a value for xref:oracle-property-database-port[`database.port`], and use the specified port value for each address in the `rac.nodes` list.
For example:
+
[source,properties]
----
database.port=1521
rac.nodes=192.168.1.100,192.168.1.101
----

* Specify a value for xref:oracle-property-database-port[`database.port`], and override the default port for one or more entries in the list.
The list can include entries that use the default `database.port` value, and entries that define their own unique port values.
For example:
+
[source,properties]
----
database.port=1521
rac.nodes=192.168.1.100,192.168.1.101:1522
----

If you supply a raw JDBC URL for the database by using the xref:oracle-property-database-url[`database.url`] property, instead of defining a value for `database.port`, each RAC node entry must explicitly specify a port value.


|[[oracle-property-skipped-operations]]<<oracle-property-skipped-operations, `+skipped.operations+`>>
|No default
|A comma-separated list of the operation types that you want the connector to skip during streaming.
You can configure the connector to skip the following types of operations:

* `c` (insert/create)
* `u` (update)
* `d` (delete)
* `t` (truncate)

By default, only truncate operations are skipped.

|[[oracle-property-signal-data-collection]]<<oracle-property-signal-data-collection,`+signal.data.collection+`>>
|No default value
a|Fully-qualified name of the data collection that is used to send xref:{link-signalling}#debezium-signaling-enabling-signaling[signals] to the connector.
When you use this property with an Oracle pluggable database (PDB), set its value to the name of the root database. +
Use the following format to specify the collection name: +
`_<databaseName>_._<schemaName>_._<tableName>_`

|[[oracle-property-incremental-snapshot-chunk-size]]<<oracle-property-incremental-snapshot-chunk-size, `+incremental.snapshot.chunk.size+`>>
|`1024`
|The maximum number of rows that the connector fetches and reads into memory during an incremental snapshot chunk.
Increasing the chunk size provides greater efficiency, because the snapshot runs fewer snapshot queries of a greater size.
However, larger chunk sizes also require more memory to buffer the snapshot data.
Adjust the chunk size to a value that provides the best performance in your environment.

|[[oracle-property-topic-naming-strategy]]<<oracle-property-topic-naming-strategy, `topic.naming.strategy`>>
|`io.debezium.schema.SchemaTopicNamingStrategy`
|The name of the TopicNamingStrategy class that should be used to determine the topic name for data change, schema change, transaction, heartbeat event etc., defaults to `SchemaTopicNamingStrategy`.

|[[oracle-property-topic-delimiter]]<<oracle-property-topic-delimiter, `topic.delimiter`>>
|`.`
|Specify the delimiter for topic name, defaults to `.`.

|[[oracle-property-topic-cache-size]]<<oracle-property-topic-cache-size, `topic.cache.size`>>
|`10000`
|The size used for holding the topic names in bounded concurrent hash map. This cache will help to determine the topic name corresponding to a given data collection.

|[[oracle-property-topic-heartbeat-prefix]]<<oracle-property-topic-heartbeat-prefix, `+topic.heartbeat.prefix+`>>
|`__debezium-heartbeat`
|Controls the name of the topic to which the connector sends heartbeat messages. The topic name has this pattern: +
 +
_topic.heartbeat.prefix_._topic.prefix_ +
 +
For example, if the topic prefix is `fulfillment`, the default topic name is `__debezium-heartbeat.fulfillment`.

|[[oracle-property-topic-transaction]]<<oracle-property-topic-transaction, `topic.transaction`>>
|`transaction`
|Controls the name of the topic to which the connector sends transaction metadata messages. The topic name has this pattern: +
 +
_topic.prefix_._topic.transaction_ +
 +
For example, if the topic prefix is `fulfillment`, the default topic name is `fulfillment.transaction`.

|===

[id="debezium-oracle-connector-database-history-configuration-properties"]
==== {prodname} Oracle connector database schema history configuration properties
include::../../partials/modules/all-connectors/ref-connector-configuration-database-history-properties.adoc[leveloffset=+1]

[id="debezium-oracle-connector-pass-through-database-driver-configuration-properties"]
==== {prodname} Oracle connector pass-through database driver configuration properties

include::{partialsdir}/modules/all-connectors/ref-connector-pass-through-database-driver-configuration-properties.adoc[leveloffset=+1]

// Type: assembly
// ModuleID: monitoring-debezium-oracle-connector-performance
// Title: Monitoring {prodname} Oracle connector performance
[[oracle-monitoring]]
== Monitoring

The {prodname} Oracle connector provides three metric types in addition to the built-in support for JMX metrics that Apache Zookeeper, Apache Kafka, and Kafka Connect have.

* xref:{link-oracle-connector}#oracle-snapshot-metrics[snapshot metrics]; for monitoring the connector when performing snapshots
* xref:{link-oracle-connector}#oracle-streaming-metrics[streaming metrics]; for monitoring the connector when processing change events
* xref:{link-oracle-connector}#oracle-schema-history-metrics[schema history metrics]; for monitoring the status of the connector's schema history

Please refer to the xref:{link-debezium-monitoring}#monitoring-debezium[monitoring documentation] for details of how to expose these metrics via JMX.

// Type: reference
// ModuleID: debezium-oracle-connector-snapshot-metrics
// Title: {prodname} Oracle connector snapshot metrics
[[oracle-snapshot-metrics]]
=== Snapshot Metrics

[[oracle-monitoring-snapshots]]

include::{partialsdir}/modules/all-connectors/frag-common-mbean-name.adoc[leveloffset=+1,tags=common-snapshot]

include::{partialsdir}/modules/all-connectors/ref-connector-monitoring-snapshot-metrics.adoc[leveloffset=+1]

include::{partialsdir}/modules/all-connectors/ref-connector-monitoring-incremental-snapshot-metrics.adoc[leveloffset=+1]

// Type: reference
// ModuleID: debezium-oracle-connector-streaming-metrics
// Title: {prodname} Oracle connector streaming metrics
[[oracle-streaming-metrics]]
=== Streaming Metrics

[[oracle-monitoring-streaming]]
include::{partialsdir}/modules/all-connectors/frag-common-mbean-name.adoc[leveloffset=+1,tags=common-streaming]

include::{partialsdir}/modules/all-connectors/ref-connector-monitoring-streaming-metrics.adoc[leveloffset=+1]

The {prodname} Oracle connector also provides the following additional streaming metrics:

.Descriptions of additional streaming metrics
[cols="45%a,25%a,30%a"]
|===
|Attributes |Type |Description

|[[oracle-streaming-metrics-currentscn]]<<oracle-streaming-metrics-currentscn, `+CurrentScn+`>>
|`string`
|The most recent system change number that has been processed.

|[[oracle-streaming-metrics-oldest-scn]]<<oracle-streaming-metrics-oldest-scn, `+OldestScn+`>>
|`string`
|The oldest system change number in the transaction buffer.

|[[oracle-streaming-metrics-committed-scn]]<<oracle-streaming-metrics-committed-scn, `+CommittedScn+`>>
|`string`
|The last committed system change number from the transaction buffer.

|[[oracle-streaming-metrics-offset-scn]]<<oracle-streaming-metrics-offset-scn, `+OffsetScn+`>>
|`string`
|The system change number currently written to the connector's offsets.

|[[oracle-streaming-metrics-currentredologfilename]]<<oracle-streaming-metrics-currentredologfilename, `+CurrentRedoLogFileName+`>>
|`string[]`
|Array of the log files that are currently mined.

|[[oracle-streaming-metrics-minimumminedlogcount]]<<oracle-streaming-metrics-minimumminedlogcount, `+MinimumMinedLogCount+`>>
|`long`
|The minimum number of logs specified for any LogMiner session.

|[[oracle-streaming-metrics-maximumminedlogcount]]<<oracle-streaming-metrics-maximumminedlogcount, `+MaximumMinedLogCount+`>>
|`long`
|The maximum number of logs specified for any LogMiner session.

|[[oracle-streaming-metrics-redologstatus]]<<oracle-streaming-metrics-redologstatus, `+RedoLogStatus+`>>
|`string[]`
|Array of the current state for each mined logfile with the format `_filename_\|_status_`.

|[[oracle-streaming-metrics-switchcounter]]<<oracle-streaming-metrics-switchcounter, `+SwitchCounter+`>>
|`int`
|The number of times the database has performed a log switch for the last day.

|[[oracle-streaming-metrics-lastcaptureddmlcount]]<<oracle-streaming-metrics-lastcaptureddmlcount, `+LastCapturedDmlCount+`>>
|`long`
|The number of DML operations observed in the last LogMiner session query.

|[[oracle-streaming-metrics-maxcaptureddmlinbatch]]<<oracle-streaming-metrics-maxcaptureddmlinbatch, `+MaxCapturedDmlInBatch+`>>
|`long`
|The maximum number of DML operations observed while processing a single LogMiner session query.

|[[oracle-streaming-metrics-totalcaptureddmlcount]]<<oracle-streaming-metrics-totalcaptureddmlcount, `+TotalCapturedDmlCount+`>>
|`long`
|The total number of DML operations observed.

|[[oracle-streaming-metrics-fetchingquerycount]]<<oracle-streaming-metrics-fetchingquerycount, `+FetchingQueryCount+`>>
|`long`
|The total number of LogMiner session query (aka batches) performed.

|[[oracle-streaming-metrics-lastdurationoffetchqueryinmilliseconds]]<<oracle-streaming-metrics-lastdurationoffetchqueryinmilliseconds, `+LastDurationOfFetchQueryInMilliseconds+`>>
|`long`
|The duration of the last LogMiner session query's fetch in milliseconds.

|[[oracle-streaming-metrics-maxdurationoffetchqueryinmilliseconds]]<<oracle-streaming-metrics-maxdurationoffetchqueryinmilliseconds, `+MaxDurationOfFetchQueryInMilliseconds+`>>
|`long`
|The maximum duration of any LogMiner session query's fetch in milliseconds.

|[[oracle-streaming-metrics-lastbatchprocessingtimeinmilliseconds]]<<oracle-streaming-metrics-lastbatchprocessingtimeinmilliseconds, `+LastBatchProcessingTimeInMilliseconds+`>>
|`long`
|The duration for processing the last LogMiner query batch results in milliseconds.

|[[oracle-streaming-metrics-totalparsetimeinmilliseconds]]<<oracle-streaming-metrics-totalparsetimeinmilliseconds, `+TotalParseTimeInMilliseconds+`>>
|`long`
|The time in milliseconds spent parsing DML event SQL statements.

|[[oracle-streaming-metrics-lastminingsessionstarttimeinmilliseconds]]<<oracle-streaming-metrics-lastminingsessionstarttimeinmilliseconds, `+LastMiningSessionStartTimeInMilliseconds+`>>
|`long`
|The duration in milliseconds to start the last LogMiner session.

|[[oracle-streaming-metrics-maxminingsessionstarttimeinmilliseconds]]<<oracle-streaming-metrics-maxminingsessionstarttimeinmilliseconds, `+MaxMiningSessionStartTimeInMilliseconds+`>>
|`long`
|The longest duration in milliseconds to start a LogMiner session.

|[[oracle-streaming-metrics-totalminingsessionstarttimeinmilliseconds]]<<oracle-streaming-metrics-totalminingsessionstarttimeinmilliseconds, `+TotalMiningSessionStartTimeInMilliseconds+`>>
|`long`
|The total duration in milliseconds spent by the connector starting LogMiner sessions.

|[[oracle-streaming-metrics-minbatchprocessingtimeinmilliseconds]]<<oracle-streaming-metrics-minbatchprocessingtimeinmilliseconds, `+MinBatchProcessingTimeInMilliseconds+`>>
|`long`
|The minimum duration in milliseconds spent processing results from a single LogMiner session.

|[[oracle-streaming-metrics-maxbatchprocessingtimeinmilliseconds]]<<oracle-streaming-metrics-maxbatchprocessingtimeinmilliseconds, `+MaxBatchProcessingTimeInMilliseconds+`>>
|`long`
|The maximum duration in milliseconds spent processing results from a single LogMiner session.

|[[oracle-streaming-metrics-totalprocessingtimeinmilliseconds]]<<oracle-streaming-metrics-totalprocessingtimeinmilliseconds, `+TotalProcessingTimeInMilliseconds+`>>
|`long`
|The total duration in milliseconds spent processing results from LogMiner sessions.

|[[oracle-streaming-metrics-totalresultsetnexttimeinmilliseconds]]<<oracle-streaming-metrics-totalresultsetnexttimeinmilliseconds, `+TotalResultSetNextTimeInMilliseconds+`>>
|`long`
|The total duration in milliseconds spent by the JDBC driver fetching the next row to be processed from the log mining view.

|[[oracle-streaming-metrics-totalprocessedrows]]<<oracle-streaming-metrics-totalprocessedrows, `+TotalProcessedRows+`>>
|`long`
|The total number of rows processed from the log mining view across all sessions.

|[[oracle-streaming-metrics-batchsize]]<<oracle-streaming-metrics-batchsize, `+BatchSize+`>>
|`int`
|The number of entries fetched by the log mining query per database round-trip.

|[[oracle-streaming-metrics-millisecondtosleepbetweenminingquery]]<<oracle-streaming-metrics-millisecondtosleepbetweenminingquery, `+MillisecondToSleepBetweenMiningQuery+`>>
|`long`
|The number of milliseconds the connector sleeps before fetching another batch of results from the log mining view.

|[[oracle-streaming-metrics-maxbatchprocessingthroughput]]<<oracle-streaming-metrics-maxbatchprocessingthroughput, `+MaxBatchProcessingThroughput+`>>
|`long`
|The maximum number of rows/second processed from the log mining view.

|[[oracle-streaming-metrics-averagebatchprocessingthroughput]]<<oracle-streaming-metrics-averagebatchprocessingthroughput, `+AverageBatchProcessingThroughput+`>>
|`long`
|The average number of rows/second processed from the log mining.

|[[oracle-streaming-metrics-lastbatchprocessingthroughput]]<<oracle-streaming-metrics-lastbatchprocessingthroughput, `+LastBatchProcessingThroughput+`>>
|`long`
|The average number of rows/second processed from the log mining view for the last batch.

|[[oracle-streaming-metrics-networkconnectionproblemscounter]]<<oracle-streaming-metrics-networkconnectionproblemscounter, `+NetworkConnectionProblemsCounter+`>>
|`long`
|The number of connection problems detected.

|[[oracle-streaming-metrics-hourstokeeptransactioninbuffer]]<<oracle-streaming-metrics-hourstokeeptransactioninbuffer, `+HoursToKeepTransactionInBuffer+`>>
|`int`
|The number of hours that transactions are retained by the connector's in-memory buffer without being committed or rolled back before being discarded.
See <<oracle-property-log-mining-transaction-retention-hours, `log.mining.transaction.retention`>> for more details.

|[[oracle-streaming-metrics-number-of-active-transactions]]<<oracle-streaming-metrics-number-of-active-transactions, `+NumberOfActiveTransactions+`>>
|`long`
|The number of current active transactions in the transaction buffer.

|[[oracle-streaming-metrics-number-of-committed-transactions]]<<oracle-streaming-metrics-number-of-committed-transactions, `+NumberOfCommittedTransactions+`>>
|`long`
|The number of committed transactions in the transaction buffer.
ifdef::community[]
|[[oracle-streaming-metrics-number-of-oversized-transactions]]<<oracle-streaming-metrics-number-of-oversized-transactions, `+NumberOfOversizedTransactions+`>>
|`long`
|The number of transactions that were discarded because their size exceeded <<oracle-property-log-mining-buffer-transaction-events-threshold, `log.mining.buffer.transaction.events.threshold`>>.
endif::community[]
|[[oracle-streaming-metrics-number-of-rolledback-transactions]]<<oracle-streaming-metrics-number-of-rolledback-transactions, `+NumberOfRolledBackTransactions+`>>
|`long`
|The number of rolled back transactions in the transaction buffer.

|[[oracle-streaming-metrics-commit-throughput]]<<oracle-streaming-metrics-commit-throughput, `+CommitThroughput+`>>
|`long`
|The average number of committed transactions per second in the transaction buffer.

|[[oracle-streaming-metrics-registered-dml-count]]<<oracle-streaming-metrics-registered-dml-count, `+RegisteredDmlCount+`>>
|`long`
|The number of registered DML operations in the transaction buffer.

|[[oracle-streaming-metrics-lag-from-source-in-milliseconds]]<<oracle-streaming-metrics-lag-from-source-in-milliseconds, `+LagFromSourceInMilliseconds+`>>
|`long`
|The time difference in milliseconds between when a change occurred in the transaction logs and when its added to the transaction buffer.

|[[oracle-streaming-metrics-max-lag-from-source-in-milliseconds]]<<oracle-streaming-metrics-max-lag-from-source-in-milliseconds, `+MaxLagFromSourceInMilliseconds+`>>
|`long`
|The maximum time difference in milliseconds between when a change occurred in the transaction logs and when its added to the transaction buffer.

|[[oracle-streaming-metrics-min-lag-from-source-in-milliseconds]]<<oracle-streaming-metrics-min-lag-from-source-in-milliseconds, `+MinLagFromSourceInMilliseconds+`>>
|`long`
|The minimum time difference in milliseconds between when a change occurred in the transaction logs and when its added to the transaction buffer.

|[[oracle-streaming-metrics-abandoned-transaction-ids]]<<oracle-streaming-metrics-abandoned-transaction-ids, `+AbandonedTransactionIds+`>>
|`string[]`
|An array of the most recent abandoned transaction identifiers removed from the transaction buffer due to their age.
See <<oracle-property-log-mining-transaction-retention-hours, `log.mining.transaction.retention.hours`>> for details.

|[[oracle-streaming-metrics-rolled-back-transaction-ids]]<<oracle-streaming-metrics-rolled-back-transaction-ids, `+RolledBackTransactionIds+`>>
|`string[]`
|An array of the most recent transaction identifiers that have been mined and rolled back in the transaction buffer.

|[[oracle-streaming-metrics-last-commit-duration-in-milliseconds]]<<oracle-streaming-metrics-last-commit-duration-in-milliseconds, `+LastCommitDurationInMilliseconds+`>>
|`long`
|The duration of the last transaction buffer commit operation in milliseconds.

|[[oracle-streaming-metrics-max-commit-duration-in-milliseconds]]<<oracle-streaming-metrics-max-commit-duration-in-milliseconds, `+MaxCommitDurationInMilliseconds+`>>
|`long`
|The duration of the longest transaction buffer commit operation in milliseconds.

|[[oracle-streaming-metrics-error-count]]<<oracle-streaming-metrics-error-count, `+ErrorCount+`>>
|`int`
|The number of errors detected.

|[[oracle-streaming-metrics-warning-count]]<<oracle-streaming-metrics-warning-count, `+WarningCount+`>>
|`int`
|The number of warnings detected.

|[[oracle-streaming-metrics-scn-freeze-count]]<<oracle-streaming-metrics-scn-freeze-count, `+ScnFreezeCount+`>>
|`int`
|The number of times that the system change number was checked for advancement and remains unchanged.
A high value can indicate that a long-running transactions is ongoing and is preventing the connector from flushing the most recently processed system change number to the connector's offsets.
When conditions are optimal, the value should be close to or equal to `0`.

|[[oracle-streaming-metrics-unparsable-ddl-count]]<<oracle-streaming-metrics-unparsable-ddl-count, `+UnparsableDdlCount+`>>
|`int`
|The number of DDL records that have been detected but could not be parsed by the DDL parser.
This should always be `0`; however when allowing unparsable DDL to be skipped, this metric can be used to determine if any warnings have been written to the connector logs.

|[[oracle-streaming-metrics-mining-session-user-global-area-memory-in-bytes]]<<oracle-streaming-metrics-mining-session-user-global-area-memory-in-bytes, `+MiningSessionUserGlobalAreaMemoryInBytes+`>>
|`long`
|The current mining session's user global area (UGA) memory consumption in bytes.

|[[oracle-streaming-metrics-mining-session-user-global-area-max-memory-in-bytes]]<<oracle-streaming-metrics-mining-session-user-global-area-max-memory-in-bytes, `+MiningSessionUserGlobalAreaMaxMemoryInBytes+`>>
|`long`
|The maximum mining session's user global area (UGA) memory consumption in bytes across all mining sessions.

|[[oracle-streaming-metrics-mining-session-process-global-area-memory-in-bytes]]<<oracle-streaming-metrics-mining-session-process-global-area-memory-in-bytes, `+MiningSessionProcessGlobalAreaMemoryInBytes+`>>
|`long`
|The current mining session's process global area (PGA) memory consumption in bytes.

|[[oracle-streaming-metrics-mining-session-process-global-area-max-memory-in-bytes]]<<oracle-streaming-metrics-mining-session-process-global-area-max-memory-in-bytes, `+MiningSessionProcessGlobalAreaMaxMemoryInBytes+`>>
|`long`
|The maximum mining session's process global area (PGA) memory consumption in bytes across all mining sessions.

|===

// Type: reference
// ModuleID: debezium-oracle-connector-schema-history-metrics
// Title: {prodname} Oracle connector schema history metrics
[[oracle-schema-history-metrics]]
=== Schema History Metrics

[[oracle-monitoring-schema-history]]

include::{partialsdir}/modules/all-connectors/ref-connector-monitoring-schema-history-metrics.adoc[leveloffset=+1]

ifdef::community[]
[[surrogate-schema-evolution]]
== Surrogate schema evolution

The Oracle connector automatically tracks and applies table schema changes by parsing DDL from the redo logs.
If the DDL parser encounters an incompatible statement, if needed, the connector provides an alternative way to apply the schema change.

By default, the connector stops when it encounters a DDL statement that it cannot parse.
You can use {prodname} link:/documentation/reference/configuration/signalling[signaling] to trigger the update of the database schema from such DDL statements.

The type of the schema update action is `schema-changes`.
This action updates the schema of all tables enumerated in the signal parameters.
The message does not contain the update to the schema.
Instead, it contains the complete new schema structure.

.Action parameters
[cols="3,9",options="header"]
|===
|Name | Description

|`database`
|The name of the Oracle database.

|`schema`
|The name of the schema where changes are applied.

|`changes`
|An array containing the requested schema updates.

|`changes.type`
|Type of the schema change, usually `ALTER`

|`changes.id`
|The fully-qualified name of the table

|`changes.table`
|The fully-qualified name of the table

|`changes.table.defaultCharsetName`
|The character set name used for the table if different from database default

|`changes.table.primaryKeyColumnNames`
|Array with the name of columns composing the primary key

|`changes.table.columns`
|Array with the column metadata

|`...columns.name`
|The name of the column

|`...columns.jdbcType`
|The JDBC type of the column as defined at link:https://docs.oracle.com/javase/8/docs/api/java/sql/Types.html[JDBC API]

|`...columns.typeName`
|The name of the column type

|`...columns.typeExpression`
|The full column type definition

|`...columns.charsetName`
|The column character set if different from the default

|`...columns.length`
|The length/size constraint of the column

|`...columns.scale`
|The scale of numeric column

|`...columns.position`
|The position of the column in the table starting with `1`

|`...columns.optional`
|Boolean `true` if column value is not mandatory

|`...columns.autoIncremented`
|Boolean `true` if column value is automatically calculated from a sequence

|`...columns.generated`
|Boolean `true` if column value is automatically calculated

|===

After the `schema-changes` signal is inserted, the connector must be restarted with an altered configuration that includes specifying the  <<{context}-property-database-history-skip-unparseable-ddl, `+schema.history.internal.skip.unparseable.ddl+`>> option as `true`.
After the connector's commit SCN advances beyond the DDL change, to prevent unparseable DDL statements from being skipped unexpectedly, return the connector configuration to its previous state.

.Example of a logging record
[cols="1,9a",options="header"]
|===
|Column | Value

|id
|`924e3ff8-2245-43ca-ba77-2af9af02fa07`

|type
|`schema-changes`

|data
|[source,json,indent=0,subs="attributes"]
----
{
   "database":"ORCLPDB1",
   "schema":"DEBEZIUM",
   "changes":[
      {
         "type":"ALTER",
         "id":"\"ORCLPDB1\".\"DEBEZIUM\".\"CUSTOMER\"",
         "table":{
            "defaultCharsetName":null,
            "primaryKeyColumnNames":[
               "ID",
               "NAME"
            ],
            "columns":[
               {
                  "name":"ID",
                  "jdbcType":2,
                  "typeName":"NUMBER",
                  "typeExpression":"NUMBER",
                  "charsetName":null,
                  "length":9,
                  "scale":0,
                  "position":1,
                  "optional":false,
                  "autoIncremented":false,
                  "generated":false
               },
               {
                  "name":"NAME",
                  "jdbcType":12,
                  "typeName":"VARCHAR2",
                  "typeExpression":"VARCHAR2",
                  "charsetName":null,
                  "length":1000,
                  "position":2,
                  "optional":true,
                  "autoIncremented":false,
                  "generated":false
               },
               {
                  "name":"SCORE",
                  "jdbcType":2,
                  "typeName":"NUMBER",
                  "typeExpression":"NUMBER",
                  "charsetName":null,
                  "length":6,
                  "scale":2,
                  "position":3,
                  "optional":true,
                  "autoIncremented":false,
                  "generated":false
               },
               {
                  "name":"REGISTERED",
                  "jdbcType":93,
                  "typeName":"TIMESTAMP(6)",
                  "typeExpression":"TIMESTAMP(6)",
                  "charsetName":null,
                  "length":6,
                  "position":4,
                  "optional":true,
                  "autoIncremented":false,
                  "generated":false
               }
            ]
         }
      }
   ]
}
----

|===

[[oracle-xstreams-support]]
== XStreams support

The {prodname} Oracle connector by default ingests changes using native Oracle LogMiner.
The connector can be toggled to use Oracle XStream instead.
To configure the connector to use Oracle XStream, you must apply specific database and connector configurations that differ from those that you use with LogMiner.

.Prerequisites

* To use the XStream API, you must have a license for the GoldenGate product.
Installing GoldenGate is not required.

=== Preparing the Database

.Configuration needed for Oracle XStream
[source,indent=0]
----
ORACLE_SID=ORCLCDB dbz_oracle sqlplus /nolog

CONNECT sys/top_secret AS SYSDBA
alter system set db_recovery_file_dest_size = 5G;
alter system set db_recovery_file_dest = '/opt/oracle/oradata/recovery_area' scope=spfile;
alter system set enable_goldengate_replication=true;
shutdown immediate
startup mount
alter database archivelog;
alter database open;
-- Should show "Database log mode: Archive Mode"
archive log list

exit;
----

In addition, supplemental logging must be enabled for captured tables or the database in order for data changes to capture the _before_ state of changed database rows.
The following illustrates how to configure this on a specific table, which is the ideal choice to minimize the amount of information captured in the Oracle redo logs.

[source,indent=0]
----
ALTER TABLE inventory.customers ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;
----

=== Creating XStream users for the connector

The {prodname} Oracle connector requires that users accounts be set up with specific permissions so that the connector can capture change events.
The following briefly describes these user configurations using a multi-tenant database model.


[[oracle-create-users-xstream]]
.Creating an XStream Administrator user
[source,indent=0]
----
sqlplus sys/top_secret@//localhost:1521/ORCLCDB as sysdba
  CREATE TABLESPACE xstream_adm_tbs DATAFILE '/opt/oracle/oradata/ORCLCDB/xstream_adm_tbs.dbf'
    SIZE 25M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED;
  exit;

sqlplus sys/top_secret@//localhost:1521/ORCLPDB1 as sysdba
  CREATE TABLESPACE xstream_adm_tbs DATAFILE '/opt/oracle/oradata/ORCLCDB/ORCLPDB1/xstream_adm_tbs.dbf'
    SIZE 25M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED;
  exit;

sqlplus sys/top_secret@//localhost:1521/ORCLCDB as sysdba
  CREATE USER c##dbzadmin IDENTIFIED BY dbz
    DEFAULT TABLESPACE xstream_adm_tbs
    QUOTA UNLIMITED ON xstream_adm_tbs
    CONTAINER=ALL;

  GRANT CREATE SESSION, SET CONTAINER TO c##dbzadmin CONTAINER=ALL;

  BEGIN
     DBMS_XSTREAM_AUTH.GRANT_ADMIN_PRIVILEGE(
        grantee                 => 'c##dbzadmin',
        privilege_type          => 'CAPTURE',
        grant_select_privileges => TRUE,
        container               => 'ALL'
     );
  END;
  /

  exit;
----

.Creating the connector's XStream user
[source,indent=0]
----
sqlplus sys/top_secret@//localhost:1521/ORCLCDB as sysdba
  CREATE TABLESPACE xstream_tbs DATAFILE '/opt/oracle/oradata/ORCLCDB/xstream_tbs.dbf'
    SIZE 25M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED;
  exit;

sqlplus sys/top_secret@//localhost:1521/ORCLPDB1 as sysdba
  CREATE TABLESPACE xstream_tbs DATAFILE '/opt/oracle/oradata/ORCLCDB/ORCLPDB1/xstream_tbs.dbf'
    SIZE 25M REUSE AUTOEXTEND ON MAXSIZE UNLIMITED;
  exit;

sqlplus sys/top_secret@//localhost:1521/ORCLCDB as sysdba
  CREATE USER c##dbzuser IDENTIFIED BY dbz
    DEFAULT TABLESPACE xstream_tbs
    QUOTA UNLIMITED ON xstream_tbs
    CONTAINER=ALL;

  GRANT CREATE SESSION TO c##dbzuser CONTAINER=ALL;
  GRANT SET CONTAINER TO c##dbzuser CONTAINER=ALL;
  GRANT SELECT ON V_$DATABASE to c##dbzuser CONTAINER=ALL;
  GRANT FLASHBACK ANY TABLE TO c##dbzuser CONTAINER=ALL;
  GRANT SELECT_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL;
  GRANT EXECUTE_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL;
  exit;
----

=== Create an XStream Outbound Server

Create an https://docs.oracle.com/cd/E11882_01/server.112/e16545/xstrm_cncpt.htm#XSTRM1088[XStream Outbound server]
(given the right privileges, this might be done automatically by the connector going forward, see {jira-url}/browse/DBZ-721[DBZ-721]):

.Create an XStream Outbound Server
[source,indent=0]
----
sqlplus c##dbzadmin/dbz@//localhost:1521/ORCLCDB
DECLARE
  tables  DBMS_UTILITY.UNCL_ARRAY;
  schemas DBMS_UTILITY.UNCL_ARRAY;
BEGIN
    tables(1)  := NULL;
    schemas(1) := 'debezium';
  DBMS_XSTREAM_ADM.CREATE_OUTBOUND(
    server_name     =>  'dbzxout',
    table_names     =>  tables,
    schema_names    =>  schemas);
END;
/
exit;
----

[NOTE]
====
When setting up an XStream Outbound Server to capture changes from a pluggable database,
the `source_container_name` parameter should be provided specifying the pluggable database name.
====

.Configure the XStream user account to connect to the XStream Outbound Server
[source,indent=0]
----
sqlplus sys/top_secret@//localhost:1521/ORCLCDB as sysdba
BEGIN
  DBMS_XSTREAM_ADM.ALTER_OUTBOUND(
    server_name  => 'dbzxout',
    connect_user => 'c##dbzuser');
END;
/
exit;
----

[NOTE]
====
A single XStream Outbound server cannot be shared by multiple {prodname} Oracle connectors.
Each connector requires a unique XStream Outbound connector to be configured.
====

[[selecting-the-adapter]]
=== Configuring the XStream adapter

By default, {prodname} uses Oracle LogMiner to ingest change events from Oracle.
You can adjust the connector configuration to enable the connector to use the Oracle XStreams adapter.

The following configuration example adds the properties `database.connection.adapter` and `database.out.server.name` to enable the connector to use the XStream API implementation.

[source,json,indent=0]
----
{
    "name": "inventory-connector",
    "config": {
        "connector.class" : "io.debezium.connector.oracle.OracleConnector",
        "tasks.max" : "1",
        "topic.prefix" : "server1",
        "database.hostname" : "<oracle ip>",
        "database.port" : "1521",
        "database.user" : "c##dbzuser",
        "database.password" : "dbz",
        "database.dbname" : "ORCLCDB",
        "database.pdb.name" : "ORCLPDB1",
        "schema.history.internal.kafka.bootstrap.servers" : "kafka:9092",
        "schema.history.internal.kafka.topic": "schema-changes.inventory",
        "database.connection.adapter": "xstream",
        "database.out.server.name" : "dbzxout"
    }
}
----

[id="obtaining-oracle-jdbc-driver-and-xstreams-api-files"]
=== Obtaining the Oracle JDBC driver and XStream API files

The {prodname} Oracle connector requires the Oracle JDBC driver (`ojdbc8.jar`) to connect to Oracle databases.
If the connector uses XStream to access the database, you must also have the XStream API (`xstreams.jar`).
Licensing requirements prohibit {prodname} from including these files in the Oracle connector archive.
However, the required files are available for free download as part of the Oracle Instant Client.
The following steps describe how to download the Oracle Instant Client and extract the required files.

.Procedure

. From a browser, download the https://www.oracle.com/database/technologies/instant-client/downloads.html[Oracle Instant Client package] for your operating system.

. Extract the archive, and then open the `instantclient___<version>__` directory.
+
For example:
+
[source]
----
instantclient_21_1/
├── adrci
├── BASIC_LITE_LICENSE
├── BASIC_LITE_README
├── genezi
├── libclntshcore.so -> libclntshcore.so.21.1
├── libclntshcore.so.12.1 -> libclntshcore.so.21.1

...

├── ojdbc8.jar
├── ucp.jar
├── uidrvci
└── xstreams.jar

----

. Copy the `ojdbc8.jar` and `xstreams.jar` files, and add them to the `_<kafka_home>_/libs` directory, for example, `kafka/libs`.
. Create an environment variable, `LD_LIBRARY_PATH`, and set its value to the path to the Instant Client directory, for example:
+
[source,bash,indent=0]
----
LD_LIBRARY_PATH=/path/to/instant_client/
----

[[oracle-xstreams-connector-properties]]
=== XStream connector properties

The following configuration properties are _required_ when using XStreams unless a default value is available.

[cols="30%a,25%a,45%a"]
|===
|Property
|Default
|Description

|[[oracle-property-database-out-server-name]]<<oracle-property-database-out-server-name, `+database.out.server.name+`>>
|No default
|Name of the XStream outbound server configured in the database.

|===

[[oracle-xstreams-dbms-lob-package]]
=== XStream and DBMS_LOB

Oracle provides a database package called `DBMS_LOB` that consists of a collection of programs to operate on BLOB, CLOB, and NCLOB columns.
Most of these programs manipulate the LOB column in totality, however, one program, `WRITEAPPEND`, is capable of manipulating a subset of the LOB data buffer.

When using XStream, `WRITEAPPEND` emits a logical change record (LCR) event for each invocation of the program.
These LCR events are not combined into a single change event like they are when using the Oracle LogMiner adapter, and so consumers of the topic should be prepared to receive events with partial column values.
This diverged behavior is captured in https://issues.redhat.com/browse/DBZ-4741[DBZ-4741] and will be addressed in a future release.


endif::community[]

// Type: concept
// ModuleID: how-debezium-oracle-connectors-handle-faults-and-problems
// Title: How {prodname} Oracle connectors handle faults and problems
[[oracle-when-things-go-wrong]]
== Behavior when things go wrong

{prodname} is a distributed system that captures all changes in multiple upstream databases; it never misses or loses an event.
When the system is operating normally or being managed carefully then {prodname} provides _exactly once_ delivery of every change event record.

If a fault occurs, {prodname} does not lose any events.
However, while it is recovering from the fault, it might repeat some change events.
In these abnormal situations, {prodname}, like Kafka, provides _at least once_ delivery of change events.

The rest of this section describes how {prodname} handles various kinds of faults and problems.

[id="oracle-logs-do-not-contain-offset-perform-new-snapshot"]
=== Logs do not contain offset, perform a new snapshot

In some cases, after the {prodname} Oracle connector restarts, it reports the following error:

[source]
----
Online REDO LOG files or archive logs do not contain the offset scn xxxxxxx. Please perform a new snapshot.
----

After the connector examines the redo and archive logs, if it cannot find the SCN that is recorded in the connector offsets, it returns the preceding error.
Because the connector uses the SCN to determine where to resume processing, if the expected SCN if not found, a new snapshot must be completed.

You might find that the `V$ARCHIVED_LOG` table contains a record with an SCN that matches the expected range.
However, the record might not be available for mining.
To be available for mining, a record must include a filename in the `NAME` column, a value of `NO` in the `DELETED` column, and a value of `A` (available) in the `STATUS` column.
If a record does not match any of these criteria, it is considered incomplete and cannot be mined.

At a minimum, archive logs must be retained for as long as the longest downtime window of the connector.

[NOTE]
====
Records that have no value in the `NAME` column no longer exist in the file system.
In such records, the value of the `DELETED` field is set to `YES`, and the `STATUS` field is set to `D` to indicate that the log is deleted.
====

[id="oracle-cannot-reference-overflow-table"]
=== ORA-25191 - Cannot reference overflow table of an index-organized table

Oracle might issue this error during the snapshot phase when encountering an index-organized table (IOT).
This error means that the connector has attempted to execute an operation that must be executed against the parent index-organized table that contains the specified overflow table.

To resolve this, the IOT name used in the SQL operation should be replaced with the parent index-organized table name.
To determine the parent index-organized table name, use the following SQL:

[source,sql]
----
SELECT IOT_NAME
  FROM DBA_TABLES
 WHERE OWNER='<tablespace-owner>'
   AND TABLE_NAME='<iot-table-name-that-failed>'
----

The connector's `table.include.list` or `table.exclude.list` configuration options should then be adjusted to explicitly include or exclude the appropriate tables to avoid the connector from attempting to capture changes from the child index-organized table.

[id="oracle-pga-aggregate-limit"]
=== ORA-04036: PGA memory used by the instance exceeds PGA_AGGREGATE_LIMIT

Oracle might report this error when {prodname} connects to a database in which changes occur infrequently.
The {prodname} connector starts an Oracle LogMiner session and reuses this session until a log switch is detected.
The reuse is both a performance and resource utilization optimization; however, a long-running mining session can cause high Program Global Area (PGA) memory usage.

If your redo log switches infrequently, you can avoid the ORA-04036 error by specifying how frequently Oracle switches logs.
A log switch causes the connector to restart the mining session, thereby avoiding high PGA memory usage.
The following configuration forces Oracle to switch log files every 20 minutes if a log switch does not occur during that interval:

[source,sql]
----
ALTER SYSTEM SET archive_lag_target=1200 scope=both;
----

Running the preceding query requires specific administrative privileges.
Coordinate with your database administrator to implement the change.

As alternative to adjusting the Oracle `ARCHIVE_LAG_TARGET` parameter, you can limit the duration of an Oracle LogMiner session by setting the connector configuration option xref:oracle-property-log-mining-session-max-ms[`log.mining.session.max.ms`].
The `log.mining.session.max.ms` option causes the LogMiner session to restart regularly, whether or not the switch to a new database log occurs.

[id="oracle-sys-system-change-not-emitted"]
=== LogMiner adapter does not capture changes made by SYS or SYSTEM

Oracle uses the `SYS` and `SYSTEM` accounts to carry out many internal changes.
When the {prodname} Oracle connector fetches changes from LogMiner, it automatically filters changes that originate from these administrator accounts.
To ensure that the connector emit event records when you change a table, never use the `SYS` or `SYSTEM` user accounts to modify the table.

[id="oracle-stops-capturing-changes-aws"]
=== Connector stops capturing changes from Oracle on AWS

Due to the https://aws.amazon.com/blogs/networking-and-content-delivery/best-practices-for-deploying-gateway-load-balancer[fixed idle timeout of 350 seconds on the AWS Gateway Load Balancer],
JDBC calls that require more than 350 seconds to complete can hang indefinitely.

In situations where calls to the Oracle LogMiner API take more than 350 seconds to complete, a timeout can be triggered, causing the AWS Gateway Load Balancer to hang.
For example, such timeouts can occur when a LogMiner session that processes large amounts of data runs concurrently with Oracle's periodic checkpointing task.

ifdef::product[]
To prevent timeouts from occurring on the AWS Gateway Load Balancer, enable keep-alive packets from the Kafka Connect environment, by performing the following steps as root or a super-user:
endif::product[]
ifdef::community[]
To prevent timeouts from occurring on the AWS Gateway Load Balancer, enable keep-alive packets from the kafka Connect or Debezium Server environment, by performing the following task as the root user or as a super-user in the environment that hosts the connector:
endif::community[]

. From a terminal, run the following command:
+
```shell
sysctl -w net.ipv4.tcp_keepalive_time=60
```
. Edit `/etc/sysctl.conf` and set the value of the following variable as shown:
+
```properties
net.ipv4.tcp_keepalive_time=60
```
. Reconfigure the {prodname} for Oracle connector to use the `database.url` property rather than `database.hostname` and add the `(ENABLE=broken)` Oracle connect string descriptor as shown in the following example:
+
```properties
database.url=jdbc:oracle:thin:username/password!@(DESCRIPTION=(ENABLE=broken)(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(Host=hostname)(Port=port)))(CONNECT_DATA=(SERVICE_NAME=serviceName)))
```

The preceding steps configure the TCP network stack to send keep-alive packets every 60 seconds.
As a result, the AWS Gateway Load Balancer does not timeout when JDBC calls to the LogMiner API take more than 350 seconds to complete, enabling the connector to continue to read changes from the database's transaction logs.

[id="oracle-oracle-11-exception-ora01882"]
=== Connection fails with error `ORA-01882: timezone region not found`

When you start a connector that the Oracle JDBC driver (`ojdbc8.jar`) to access an Oracle 11g database, the connector might report the following error:

```shell
Caused by: java.sql.SQLException: ORA-00604: error occurred at recursive SQL level 1
ORA-01882: timezone region not found
```

To prevent the preceding error from occurring, add the following setting to the connector configuration: `database.oracle.jdbc.timezoneAsRegion=false`.
