MySQL Internals Manual  /  The Binary Log  /  Event Meanings

20.6 Event Meanings

The following descriptions briefly summarize the meaning of each event type:

  • UNKNOWN_EVENT

    This event type should never occur. It is never written to a binary log. If an event is read from a binary log that cannot be recognized as something else, it is treated as UNKNOWN_EVENT.

  • START_EVENT_V3

    A descriptor event that is written to the beginning of the each binary log file. (In MySQL 4.0 and 4.1, this event is written only to the first binary log file that the server creates after startup.) This event is used in MySQL 3.23 through 4.1 and superseded in MySQL 5.0 by FORMAT_DESCRIPTION_EVENT.

  • QUERY_EVENT

    Written when an updating statement is done.

  • STOP_EVENT

    Written when mysqld stops.

  • ROTATE_EVENT

    Written when mysqld switches to a new binary log file. This occurs when someone issues a FLUSH LOGS statement or the current binary log file becomes too large. The maximum size is determined by max_binlog_size.

  • INTVAR_EVENT

    Written every time a statement uses an AUTO_INCREMENT column or the LAST_INSERT_ID() function; precedes other events for the statement. This is written only before a QUERY_EVENT and is not used with row-based logging. An INTVAR_EVENT is written with a "subtype" in the event data part:

    • INSERT_ID_EVENT indicates the value to use for an AUTO_INCREMENT column in the next statement.

    • LAST_INSERT_ID_EVENT indicates the value to use for the LAST_INSERT_ID() function in the next statement.

  • LOAD_EVENT

    Used for LOAD DATA INFILE statements in MySQL 3.23. See LOAD DATA INFILE Events.

  • SLAVE_EVENT

    Not used.

  • CREATE_FILE_EVENT

    Used for LOAD DATA INFILE statements in MySQL 4.0 and 4.1. See LOAD DATA INFILE Events.

  • APPEND_BLOCK_EVENT

    Used for LOAD DATA INFILE statements as of MySQL 4.0. See LOAD DATA INFILE Events.

  • EXEC_LOAD_EVENT

    Used for LOAD DATA INFILE statements in 4.0 and 4.1. See LOAD DATA INFILE Events.

  • DELETE_FILE_EVENT

    Used for LOAD DATA INFILE statements as of MySQL 4.0. See LOAD DATA INFILE Events.

  • NEW_LOAD_EVENT

    Used for LOAD DATA INFILE statements in MySQL 4.0 and 4.1. See LOAD DATA INFILE Events.

  • RAND_EVENT

    Written every time a statement uses the RAND() function; precedes other events for the statement. Indicates the seed values to use for generating a random number with RAND() in the next statement. This is written only before a QUERY_EVENT and is not used with row-based logging.

  • USER_VAR_EVENT

    Written every time a statement uses a user variable; precedes other events for the statement. Indicates the value to use for the user variable in the next statement. This is written only before a QUERY_EVENT and is not used with row-based logging.

  • FORMAT_DESCRIPTION_EVENT

    A descriptor event that is written to the beginning of the each binary log file. This event is used as of MySQL 5.0; it supersedes START_EVENT_V3.

  • XID_EVENT

    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).

  • BEGIN_LOAD_QUERY_EVENT

    Used for LOAD DATA INFILE statements as of MySQL 5.0. See LOAD DATA INFILE Events.

  • EXECUTE_LOAD_QUERY_EVENT

    Used for LOAD DATA INFILE statements as of MySQL 5.0. See LOAD DATA INFILE Events.

  • TABLE_MAP_EVENT

    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.

  • PRE_GA_WRITE_ROWS_EVENT

    Obsolete version of WRITE_ROWS_EVENT.

  • PRE_GA_UPDATE_ROWS_EVENT

    Obsolete version of UPDATE_ROWS_EVENT.

  • PRE_GA_DELETE_ROWS_EVENT

    Obsolete version of DELETE_ROWS_EVENT.

  • WRITE_ROWS_EVENT

    Used for row-based binary logging. This event logs inserts of rows in a single table.

  • UPDATE_ROWS_EVENT

    Used for row-based binary logging. This event logs updates of rows in a single table.

  • DELETE_ROWS_EVENT

    Used for row-based binary logging. This event logs deletions of rows in a single table.

  • INCIDENT_EVENT

    Used to log an out of the ordinary event that occurred on the master. It notifies the slave that something happened on the master that might cause data to be in an inconsistent state.

  • HEARTBEAT_LOG_EVENT

    Sent by a master to a slave to let the slave know that the master is still alive. Not written to log files.


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