QUERY_EVENT

This event is written into the binary log file for:

• Statement-based replication (updating statements).

• DDLs.

• COMMIT related to nontransactional engines (like MyISAM or BLACKHOLE).

Header

• Event Type = 0x02.

Fields

Fixed data part:

• The ID of the thread that issued this statement on the master.

• The time in seconds that the statement took to execute.

• The length of the name of the database which was the default database when the statement was executed. This name appears later, in the variable data part. It is necessary for statements such as INSERT INTO t VALUES(1) that don't specify the database and rely on the default database previously selected by USE.

Variable data part:

• Zero or more status variables. Each status variable consists of one byte code identifying the variable stored, followed by the value of the variable. The format of the value is variable-specific. The number of bytes 'n' is the length of the status variable block (read in fixed data part).

• The default database name (null-terminated).

• The SQL statement. By subtraction the size of the statement can be known.

Status variables

Q_FLAGS2_CODE (0x00)

• bitmask.

Q_SQL_MODE_CODE (0x01)

• 8-byte bitmask.

Q_CATALOG_NZ_CODE (0x02)

• length

• catalog name + '\0'

Q_AUTO_INCREMENT (0x03)

• auto_increment increment

• auto_increment offset

Q_CHARSET_CODE (0x04)

• client character set

• collation_connection

• collation_server

Q_TIMEZONE_CODE (0x05)

• length

• time zone

Q_CATALOG_NZ_CODE (0x06)

• length

• catalog

Q_LC_TIME_NAMES_CODE (0x07)

• code The mapping between code and names are defined in sql_locale.cc.

Q_CHARSET_DATABASE_CODE (0x08)

• database collation

Q_TABLE_MAP_FOR_UPDATE_CODE (0x09)

• table bittmask Every bit of this variable represents a table, and is set to 1 if the corresponding table is to be updated by this statement.

Q_MASTER_DATA_WRITTEN_CODE (0x0A)

• Not in use any more

• original event length

Q_INVOKER (0x0B|)

• user name length

• user name

• host name length

• host name

Q_UPDATED_DB_NAMES (0x0C)

• MySQL only

• count

• for (i=0;i < count; i++)

  • Null terminated database name

Q_MICROSECONDS (0x0D)

• MySQL only

• microsecond part

Q_HRNOW (0x80)

• MariaDB only

• microsecond part

Q_XID (0x81)

• MariaDB only

• xid

Example With CRC32

Header, 19 Bytes

• Event Time[4] = 71 17 28 5a ===> 1512576881.

• Event Type[1] = 2.

• Server_id[4] = 8c 27 00 00 ===> 10124.

• Event Size = 55 00 00 00 ===> 85.

Content, Variable Data

• Thread ID[4] = 66 01 00 00 ===> 358.

• Execution Time[4] = 00 00 00 00 => 0 seconds.

• Statement default database name len[1] = 00 => 0 (no default database).

• Error code[2] = 00 00 => 0 (no errors).

CRC32, 4 Bytes

• 4a 69 9e ed.

Example With Default Database and CRC32

Content, Variable Data

• Thread ID[4] = 66 01 00 00 ===> 358.

• Execution Time[4] = 10 00 00 00 => 1 second.

• Statement default database name len[1] = 04 => 4 (default database is "test").

• Error code[2] = 00 00 => 0 (no errors).

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