Added explicit support for handling `CHARSET` as an alias for `CHARACTER SET` in both tables and columns. `CREATE DATABASE` and `ALTER DATABASE` statements can also specify character sets, but the DDL parser handles but does not explicitly parse them so no modification is needed for them. Several unit tests were added to confirm the behavior.
The new envelope Struct contains fields for the local time at which the connector processed the event, the kind of operation (e.g., read, insert, update, or delete), the state of the record before and after the change, and the information about the event source. The latter two items are connector-specific. The timestamp is merely the time using the connector's process clock, and no guarantees are provided about accuracy, monotonicity, or relationship to the original source event.
The envelope structure is now used as the value for each event message in the MySQL connector; they keys of the event messages remain unchanged. Note that to facilitate Kafka log compaction (which requires a null value), a delete event containing the envelope with details about the deletion is followed by a "tombstone" event that contains the same key but null value.
An example of a message value with this new envelope is as follows:
{
"schema" : {
"type" : "struct",
"fields" : [ {
"type" : "struct",
"fields" : [ {
"type" : "int32",
"optional" : false,
"name" : "org.apache.kafka.connect.data.Date",
"version" : 1,
"field" : "order_date"
}, {
"type" : "int32",
"optional" : false,
"field" : "purchaser"
}, {
"type" : "int32",
"optional" : false,
"field" : "quantity"
}, {
"type" : "int32",
"optional" : false,
"field" : "product_id"
} ],
"optional" : true,
"name" : "connector_test.orders",
"field" : "before"
}, {
"type" : "struct",
"fields" : [ {
"type" : "int32",
"optional" : false,
"name" : "org.apache.kafka.connect.data.Date",
"version" : 1,
"field" : "order_date"
}, {
"type" : "int32",
"optional" : false,
"field" : "purchaser"
}, {
"type" : "int32",
"optional" : false,
"field" : "quantity"
}, {
"type" : "int32",
"optional" : false,
"field" : "product_id"
} ],
"optional" : true,
"name" : "connector_test.orders",
"field" : "after"
}, {
"type" : "struct",
"fields" : [ {
"type" : "string",
"optional" : false,
"field" : "server"
}, {
"type" : "string",
"optional" : false,
"field" : "file"
}, {
"type" : "int64",
"optional" : false,
"field" : "pos"
}, {
"type" : "int32",
"optional" : false,
"field" : "row"
} ],
"optional" : false,
"name" : "io.debezium.connector.mysql.Source",
"field" : "source"
}, {
"type" : "string",
"optional" : false,
"field" : "op"
}, {
"type" : "int64",
"optional" : true,
"field" : "ts"
} ],
"optional" : false,
"name" : "kafka-connect-2.connector_test.orders",
"version" : 1
},
"payload" : {
"before" : null,
"after" : {
"order_date" : 16852,
"purchaser" : 1003,
"quantity" : 1,
"product_id" : 107
},
"source" : {
"server" : "kafka-connect-2",
"file" : "mysql-bin.000002",
"pos" : 2887680,
"row" : 4
},
"op" : "c",
"ts" : 1463437199134
}
}
Notice how the Schema is significantly larger, since it must describe all of the envelope's fields even when those fields are not used. In this case, the event signifies that a record was created as the 4th record of a single event recorded in the binlog.
When a row is updated in the database and the primary/unique key for that table is changed, the MySQL connector continues to generate an update event with the new key and new value, but now also generates a tombstone event for the old key. This ensures that when a Kafka topic is compacted, all prior events with the old key will (eventually) be removed. It also ensures that consumers see that the row represented by the old key has been removed.
MySQL 5.6 using the MyISAM engine will create the `help_relation` system table using a CREATE TABLE statement that does not have in the columns' REFERENCE clause a list of columns in the referenced table. MySQL 5.7 using the InnoDB engine does not include the REFERENCE clauses.
Because Debezium's MySQL DDL parser is meant only to understand the statements recorded in the binlog, it does not have to validate the statements and therefore the DDL parser can be a bit more lenient by not requiring the list of columns in a REFERENCE clause in a CREATE TABLE statement's column definitions.
This commit also adds several unit tests that validate all of the DDL statements used by MySQL 5.6 and 5.7 during startup (in the configurations used in our integration tests).
Changed the MySQL connector to use comma-separated lists of regular expressions for the database
and table whitelist/blacklists. Literals are still accepted and will match fully-qualified table names,
although the '.' character used as a delimiter is also a special character in regular expressions and
therefore may need to be escaped with a double backslash ('\\') to more carefully match fully-qualified
table names.
Added several new configuration properties for the MySQL connector that instruct it to hide,
truncate, and/or mask certain columns. The properties' values are all lists of regular expressions
or literal fully-qualified column names. For example, the following configuration property:
column.blacklist=server.users.picture,server.users.other
will cause the connector to leave out of change event messages for the `server.users` table those
fields that correspond to the `picture` and `others` columns. This capability can be used to
This capability can be used to prevent dissemination of sensitive information in the change event
stream.
An alternative to blacklisting is masking. The following configuration property:
column.mask.with.10.chars=server\\.users\\.(\\w*email)
will cause the connector to mask in the change event messages for the `server.users` table
all values for columns whose name ends in `email`. The values will be replaced in this case with
a constant string of 10 asterisk ('*') characters, even when the email value is null.
This capability can also be used to prevent dissemination of sensitive information in the change event
stream.
Another option is to truncate string values for specific columns. The following configuration
property:
column.truncate.to.120.chars=server[.]users[.](description|biography)
will cause the connector to truncate to at most 120 characters the values of the `description` and
`biography` columns in the change event messages for the `server.users` table. Although this example
used a limit of 120 characters, any positive length can be specified; separate properties should
be used when different lengths are required. Note how the '.' delimiter in the fully-qualified names
is escaped since that same character is a special character in regular expressions. This capability
can be used to reduce the size of change event messages.
Drop table/view statements that involve more than one table generate one event for each table/view. Previously, each of those statements had the original multi-table/view statement. Now, each event has a statement that applies to only that table (generated from the original with all the same clauses).
The previous change did not correctly capture the statements for a `RENAME TO` that renamed multiple tables, so fixed the code so that it generates a single `RENAME TO` for each table rename.
Refactored the mechanism by which components can listen to the activities of a DDL parser. The new approach
should be significantly more flexible for additional types of DDL events while making it easier to maintain
backward compatibility. It also will enable passing event-specific information on each DDL event.
There is no point in sending a record that contains a null key and null value. While this may not be likely for insert or update cases (since at least the value should not be null), it is possible when a row is deleted (meaning the record value will be null) but the table has no primary/unique key (meaning the record key will be null).
Corrects a bug where a deleted row was written to Kafka in the same as an insert, making them indistinguishable. Now, a deleted row is written with the row's primary/unique key as the record key, and a null record value. Note that if the row has no primary/unique key, no record is written to Kafka.
