Improves PostgreSQL RecordsStreamProducer performance for processing up
dates to a table with TOASTable columns, where those updates do not
affect said columns. Prior to this fix, these updates would trigger a
refresh of the in-memory table schema. In the worst case, this means a
query for every update. This puts significant load on the database
server and adds tens of milliseconds to the processing of each update
record.
The fix requires a new configuration option, called
'schema.refresh.mode'. This option has values 'columns_diff' (the
default) and 'columns_diff_exclude_unchanged_toast'. 'columns_diff'
maintains the pre-fix behavior. 'columns_diff_exclude_unchanged_toast'
activates the fix.
The fix must be toggleable because it decreases the consistency guarantees
Debezium provides, since in-memory table schemas may not stay
synchronized with their remote counterparts. With type metadata included
in the replication message, inconsistencies are limited to the unchanged
toast columns.
* Using database encoding for string conversion
* Not making hstore schemas optional by default
* Using Jackson instead of GSon for JSON serialization
* Removing superfluous method and log messages
* Adjusting to naming and style conventions
* Changing field.renames delimiter from equal to colon character
* Adding examples of source document structure to tests
* Adding tests for case: two renames have the same target field
* Adding missing return
* Changing Path interface to abstract class
The "field.renames" configuration property is an optional comma-separated list of the fully-qualified replacements of fields that should be used to rename fields in change event message values. Fully-qualified replacements for fields are of the form "databaseName.collectionName.fieldName.nestedFieldName=newNestedFieldName", where "databaseName" and "collectionName" may contain the wildcard (*) which matches any characters, the equal character (=) is used to determine rename mapping of field.
The "field.blacklist" configuration property is an optional comma-separated list of the fully-qualified names of fields that should be excluded from change event message values. Fully-qualified names for fields are of the form "databaseName.collectionName.fieldName.nestedFieldName", where "databaseName" and "collectionName" may contain the wildcard (*) which matches any characters.
Although the "field.blacklist" configuration property allows you to remove fields from the event values, the "_id" field is always included in the event’s key.
