binlog-event-routing.md

Binlog Event Routing

The following MySQL binlog events are dispatched by the ChangeStreamEventListener:

TABLE_MAP

Used for row-based binary logging. This event precedes each row operation event. It maps a table definition to a number, where the table definition consists of database and table names and column definitions. The purpose of this event is to enable replication when a table has different definitions on the master and slave. Row operation events that belong to the same transaction may be grouped into sequences, in which case each such sequence of events begins with a sequence of TABLE_MAP_EVENT events: one per table used by events in the sequence.

TABLE_MAP events are used by the ChangeStreamEventDeserializer to deserialize MutationEvents that include database and tableName info.

ROWS_QUERY

Contains the SQL query that was executed to produce the row events immediately following this event.

ROWS_QUERY events are used by the ChangeStreamEventDeserializer to deserialize MutationEvents that include the event's sql query string.

*Note: In order to include sql with the mutation events, you must enable the binlog_rows_query_log_events setting in my.cnf.

QUERY

QUERY events are converted into one of several objects:

• AlterTableEvent is delivered to the ColumnInfoActor (signaling that the table's cache should be expired and refreshed)
• BeginTransaction is delivered to the TransactionActor
• CommitTransaction is delivered to the TransactionActor
• RollbackTransaction is delivered to the TransactionActor

####ROWS_EVENT (aka Mutations) Mutations (i.e. Inserts, Updates and Deletes) can be represented by several binlog events, together referred to as ROWS_EVENT:

• WRITE_ROWS and EXT_WRITE_ROWS are converted to Insert and delivered to the TransactionActor.
• UPDATE_ROWS and EXT_UPDATE_ROWS are converted to Update and delivered to the TransactionActor.
  • Note: Update events are different from Insert and Delete in that they contain both the old and the new values for the record.
• DELETE_ROWS and EXT_DELETE_ROWS are converted to Delete and delivered to the TransactionActor.

####XID Generated for a commit of a transaction that modifies one or more tables of an XA-capable storage engine. Normal transactions are implemented by sending a QUERY_EVENT containing a BEGIN statement and a QUERY_EVENT containing a COMMIT statement (or a ROLLBACK statement if the transaction is rolled back).

XID_EVENT events, indicative of the end of a transaction, are converted to CommitTransaction and delivered to the TransactionActor.

####GTID Written to the binlog prior to the mutations in it's transaction, GTID event contains the gtid of the transaction, and is added to each mutation event to allow consumers to group events by transaction (if desired).

GTID events are converted to GtidEvent and delivered to the TransactionActor.