Package io.debezium.connector.oracle.logminer.processor

Class TransactionCommitConsumer

  • All Implemented Interfaces:
    BlockingConsumer<LogMinerEvent>, AutoCloseable
    public class TransactionCommitConsumer
extends Object
implements AutoCloseable, BlockingConsumer<LogMinerEvent>
    A consumer of transaction events at commit time that is capable of inspecting the event stream, merging events that should be merged when LOB support is enabled, and then delegating the final stream of events to a delegate consumer. When a table has a LOB field, Oracle LogMiner often supplies us with synthetic events that deal with sub-tasks that occur in the database as a result of writing LOB data to the database. We would prefer to emit these synthetic events as a part of the overall logical event, whether that is an insert or update. An example of a scenario would be the following logical user action: INSERT INTO my_table (id,lob_field) values (1, 'some clob data'); Oracle LogMiner provides the connector with the following events: INSERT INTO my_table (id,lob_field) values (1, EMPTY_CLOB()); UPDATE my_table SET lob_field = 'some clob data' where id = 1; When LOB support is enabled, this consumer implementation will detect that the update is an event that should be merged with the previous insert event so that the emitted change events consists a single logical change, an insert that have an after section like: 
         "after": {
         "id": 1,
         "lob_field": "some clob data"
     }
    When LOB support isn't enabled, events are simply passed through to the delegate and no event inspection, merging, or buffering occurs.
    Author:
    Chris Cranford