浅析MySQL基于ROW格式的二进制日志

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上文分析的二进制日志实际上是基于STATEMENT格式的，下面我们来看看基于ROW格式的二进制日志，毕竟，两者对应的binlog事件类型也不一样，同时，很多童鞋反映基于ROW格式的二进制日志无法查到原生的DML语句，关于这个问题，其实官方也给出了解决方案，下面，将一一揭晓。

首先，来几条测试数据

mysql> set binlog_format=row;
Query OK, 0 rows affected (0.00 sec)mysql> flush logs;
Query OK, 0 rows affected (0.01 sec)mysql> insert into test.t1 values(1,'a');
Query OK, 1 row affected (0.00 sec)mysql> use testDatabase changed
mysql> insert into t1 values(2,'b');
Query OK, 1 row affected (0.00 sec)mysql> update t1 set name='c' where id=2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0mysql> delete from t1 where id=1;
Query OK, 1 row affected (0.01 sec)

首先通过SHOW BINLOG EVENTS查看二进制日志中的内容

mysql> show binlog events in 'mysql-bin.000025';
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
| mysql-bin.000025 | 4 | Format_desc | 1 | 120 | Server ver: 5.6.31-log, Binlog ver: 4 |
| mysql-bin.000025 | 120 | Query | 1 | 188 | BEGIN |
| mysql-bin.000025 | 188 | Table_map | 1 | 236 | table_id: 79 (test.t1) |
| mysql-bin.000025 | 236 | Write_rows | 1 | 278 | table_id: 79 flags: STMT_END_F |
| mysql-bin.000025 | 278 | Xid | 1 | 309 | COMMIT /* xid=175 */ |
| mysql-bin.000025 | 309 | Query | 1 | 381 | BEGIN |
| mysql-bin.000025 | 381 | Table_map | 1 | 429 | table_id: 79 (test.t1) |
| mysql-bin.000025 | 429 | Write_rows | 1 | 471 | table_id: 79 flags: STMT_END_F |
| mysql-bin.000025 | 471 | Xid | 1 | 502 | COMMIT /* xid=183 */ |
| mysql-bin.000025 | 502 | Query | 1 | 574 | BEGIN |
| mysql-bin.000025 | 574 | Table_map | 1 | 622 | table_id: 79 (test.t1) |
| mysql-bin.000025 | 622 | Update_rows | 1 | 672 | table_id: 79 flags: STMT_END_F |
| mysql-bin.000025 | 672 | Xid | 1 | 703 | COMMIT /* xid=184 */ |
| mysql-bin.000025 | 703 | Query | 1 | 775 | BEGIN |
| mysql-bin.000025 | 775 | Table_map | 1 | 823 | table_id: 79 (test.t1) |
| mysql-bin.000025 | 823 | Delete_rows | 1 | 865 | table_id: 79 flags: STMT_END_F |
| mysql-bin.000025 | 865 | Xid | 1 | 896 | COMMIT /* xid=185 */ |
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
17 rows in set (0.00 sec)

再来通过mysqlbinlog查看

# mysqlbinlog mysql-bin.000025

/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at
# :: server id end_log_pos CRC32 0x5b15ac4f Start: binlog v , server v 5.6.-log created ::
# Warning: this binlog is either in use or was not closed properly.
BINLOG '
4MmzVw8BAAAAdAAAAHgAAAABAAQANS42LjMxLWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAXAAEGggAAAAICAgCAAAACgoKGRkAAU+s
FVs=
'/*!*/;
# at
# :: server id end_log_pos CRC32 0x005847f0 Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
SET @@session.pseudo_thread_id=/*!*/;
SET @@session.foreign_key_checks=, @@session.sql_auto_is_null=, @@session.unique_checks=, @@session.autocommit=/*!*/;
SET @@session.sql_mode=/*!*/;
SET @@session.auto_increment_increment=, @@session.auto_increment_offset=/*!*/;
/*!\C utf8 *//*!*/;
SET @@session.character_set_client=,@@session.collation_connection=,@@session.collation_server=/*!*/;
SET @@session.lc_time_names=/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x2b8d2069 Table_map: `test`.`t1` mapped to number
# at
# :: server id end_log_pos CRC32 0xadc98fbc Write_rows: table id flags: STMT_END_FBINLOG '
5smzVxMBAAAAMAAAAOwAAAAAAE8AAAAAAAEABHRlc3QAAnQxAAIDDwIeAANpII0r
5smzVx4BAAAAKgAAABYBAAAAAE8AAAAAAAEAAgAC//wBAAAAAWG8j8mt
'/*!*/;
# at
# :: server id end_log_pos CRC32 0x552dc682 Xid =
COMMIT/*!*/;
# at
# :: server id end_log_pos CRC32 0x17d8173e Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x71a27e19 Table_map: `test`.`t1` mapped to number
# at
# :: server id end_log_pos CRC32 0xefda98ca Write_rows: table id flags: STMT_END_FBINLOG '
8smzVxMBAAAAMAAAAK0BAAAAAE8AAAAAAAEABHRlc3QAAnQxAAIDDwIeAAMZfqJx
8smzVx4BAAAAKgAAANcBAAAAAE8AAAAAAAEAAgAC//wCAAAAAWLKmNrv
'/*!*/;
# at
# :: server id end_log_pos CRC32 0x7bed11c4 Xid =
COMMIT/*!*/;
# at
# :: server id end_log_pos CRC32 0xd164b750 Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x9fa3cabc Table_map: `test`.`t1` mapped to number
# at
# :: server id end_log_pos CRC32 0xb1646398 Update_rows: table id flags: STMT_END_FBINLOG '
9smzVxMBAAAAMAAAAG4CAAAAAE8AAAAAAAEABHRlc3QAAnQxAAIDDwIeAAO8yqOf
9smzVx8BAAAAMgAAAKACAAAAAE8AAAAAAAEAAgAC///8AgAAAAFi/AIAAAABY5hjZLE=
'/*!*/;
# at
# :: server id end_log_pos CRC32 0x91a90c52 Xid =
COMMIT/*!*/;
# at
# :: server id end_log_pos CRC32 0x5ae24c0b Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x33c52e84 Table_map: `test`.`t1` mapped to number
# at
# :: server id end_log_pos CRC32 0x77e907a2 Delete_rows: table id flags: STMT_END_FBINLOG '
+8mzVxMBAAAAMAAAADcDAAAAAE8AAAAAAAEABHRlc3QAAnQxAAIDDwIeAAOELsUz
+8mzVyABAAAAKgAAAGEDAAAAAE8AAAAAAAEAAgAC//wBAAAAAWGiB+l3
'/*!*/;
# at
# :: server id end_log_pos CRC32 0xb0988385 Xid =
COMMIT/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

额，what is this，竟然没看到一条明文的DML语句

实际上，对于ROW格式的二进制日志，需要使用如下方式查看，这也是STATEMENT和ROW格式的差异之一

# mysqlbinlog mysql-bin.000025 -vv --base64-output=decode-rows

/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at
# :: server id end_log_pos CRC32 0x5b15ac4f Start: binlog v , server v 5.6.-log created ::
# Warning: this binlog is either in use or was not closed properly.
# at
# :: server id end_log_pos CRC32 0x005847f0 Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
SET @@session.pseudo_thread_id=/*!*/;
SET @@session.foreign_key_checks=, @@session.sql_auto_is_null=, @@session.unique_checks=, @@session.autocommit=/*!*/;
SET @@session.sql_mode=/*!*/;
SET @@session.auto_increment_increment=, @@session.auto_increment_offset=/*!*/;
/*!\C utf8 *//*!*/;
SET @@session.character_set_client=,@@session.collation_connection=,@@session.collation_server=/*!*/;
SET @@session.lc_time_names=/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x2b8d2069 Table_map: `test`.`t1` mapped to number
# at
# :: server id end_log_pos CRC32 0xadc98fbc Write_rows: table id flags: STMT_END_F
### INSERT INTO `test`.`t1`
### SET
### @= /* INT meta=0 nullable=1 is_null=0 */
### @='a' /* VARSTRING(30) meta=30 nullable=1 is_null=0 */
# at
# :: server id end_log_pos CRC32 0x552dc682 Xid =
COMMIT/*!*/;
# at
# :: server id end_log_pos CRC32 0x17d8173e Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x71a27e19 Table_map: `test`.`t1` mapped to number 79
# at
# :: server id end_log_pos CRC32 0xefda98ca Write_rows: table id flags: STMT_END_F
### INSERT INTO `test`.`t1`
### SET
### @= /* INT meta=0 nullable=1 is_null=0 */
### @='b' /* VARSTRING(30) meta=30 nullable=1 is_null=0 */
# at
# :: server id end_log_pos CRC32 0x7bed11c4 Xid =
COMMIT/*!*/;
# at
# :: server id end_log_pos CRC32 0xd164b750 Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x9fa3cabc Table_map: `test`.`t1` mapped to number 79
# at
# :: server id end_log_pos CRC32 0xb1646398 Update_rows: table id flags: STMT_END_F
### UPDATE `test`.`t1`
### WHERE
### @= /* INT meta=0 nullable=1 is_null=0 */
### @='b' /* VARSTRING(30) meta=30 nullable=1 is_null=0 */
### SET
### @= /* INT meta=0 nullable=1 is_null=0 */
### @='c' /* VARSTRING(30) meta=30 nullable=1 is_null=0 */
# at
# :: server id end_log_pos CRC32 0x91a90c52 Xid =
COMMIT/*!*/;
# at
# :: server id end_log_pos CRC32 0x5ae24c0b Query thread_id= exec_time= error_code=
SET TIMESTAMP=/*!*/;
BEGIN
/*!*/;
# at
# :: server id end_log_pos CRC32 0x33c52e84 Table_map: `test`.`t1` mapped to number 79
# at
# :: server id end_log_pos CRC32 0x77e907a2 Delete_rows: table id flags: STMT_END_F
### DELETE FROM `test`.`t1`
### WHERE
### @= /* INT meta=0 nullable=1 is_null=0 */
### @='a' /* VARSTRING(30) meta=30 nullable=1 is_null=0 */
# at
# :: server id end_log_pos CRC32 0xb0988385 Xid =
COMMIT/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

对于STATEMENT格式的binlog，所有的DML操作都记录在QUERY_EVENT中，而对于ROW格式的binlog，所有的DML操作都记录在ROWS_EVENT中，ROWS_EVENT分为三种：WRITE_ROWS_EVENT，UPDATE_ROWS_EVENT，DELETE_ROWS_EVENT，分别对应insert，update和delete操作。

对于insert操作，WRITE_ROWS_EVENT包含了要插入的数据

对于update操作，UPDATE_ROWS_EVENT不仅包含了修改后的数据，还包含了修改前的值。

对于delete操作，仅仅需要指定删除的主键（在没有主键的情况下，会给定所有列）

事实上，在ROW格式的binlog文件中，每个ROWS_EVENT事件前都会有一个TABLE_MAP_EVENT，用于描述表的内部id和结构定义。

即便上述两个insert操作，一个没有执行use test操作，都不影响TABLE_MAP_EVENT的内容，这也会导致基于ROW格式下的库级别的复制和基于STATEMENT格式下库级别的复制的复制规则不一致。

如何在ROW格式中输出原生的DML语句？

MySQL实际上提供了一个参数，可以用于输出原生的DML语句，但是该语句仅仅是其注释的作用，并不会被应用。

如下所示，

mysql> flush logs;
Query OK, 0 rows affected (0.01 sec)mysql> set binlog_rows_query_log_events=1;
Query OK, 0 rows affected (0.01 sec)mysql> insert into t1 values(3,'c');
Query OK, 1 row affected (0.00 sec)

对应的二进制的内容如下：

mysql> show binlog events in 'mysql-bin.000026';
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
| mysql-bin.000026 | 4 | Format_desc | 1 | 120 | Server ver: 5.6.31-log, Binlog ver: 4 |
| mysql-bin.000026 | 120 | Query | 1 | 192 | BEGIN |
| mysql-bin.000026 | 192 | Rows_query | 1 | 244 | # insert into t1 values(3,'c') |
| mysql-bin.000026 | 244 | Table_map | 1 | 292 | table_id: 79 (test.t1) |
| mysql-bin.000026 | 292 | Write_rows | 1 | 334 | table_id: 79 flags: STMT_END_F |
| mysql-bin.000026 | 334 | Xid | 1 | 365 | COMMIT /* xid=189 */ |
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
6 rows in set (0.00 sec)

实际上，MySQL新增了一个事务类型来输出ROW格式中原生的DML语句，即ROWS_QUERY_EVENT。

自此以后，再也不用顾虑ROW格式的二进制日志中无法查看原生的DML语句了。

参考

1. MariaDB原理与实现