背景

先前开源了一个开源项目： 【阿里巴巴开源项目: 基于mysql数据库binlog的增量订阅&消费】 

本文主要是介绍一下canal支持mariadb协议上的变化. 

协议变化

mariadb5.5

mariadb5.5主要是基于mysql5.5的原型，类型定义基本没啥变化，大体上都保持兼容

主要的变化：

1. QueryLogEvent增加了status变量.    

• Q_HRNOW  用于记录毫秒的精度，枚举值下标为128

协议解析的时候，需要处理Q_HRNOW，需要跳过3字节的数据.  

ps.  mysql5.6后，新增了Q_MICROSECONDS来支持mariaDb中Q_HRNOW的毫秒精度的功能.  

2. binlog事件的变化

1./* New MySQL/Sun events are to be added right above this comment */  
2.MYSQL_EVENTS_END,  
3.  
4.MARIA_EVENTS_BEGIN= 160,  
5./* New Maria event numbers start from here */  
6.ANNOTATE_ROWS_EVENT= 160,  
7.  
8./* Add new MariaDB events here - right above this comment!  */  
9.  
10.ENUM_END_EVENT /* end marker */  

  /* New MySQL/Sun events are to be added right above this comment */
  MYSQL_EVENTS_END,

  MARIA_EVENTS_BEGIN= 160,
  /* New Maria event numbers start from here */
  ANNOTATE_ROWS_EVENT= 160,

  /* Add new MariaDB events here - right above this comment!  */

  ENUM_END_EVENT /* end marker */

新增了mariadb的binlog区间为160开始，ANNOTATE_ROWS_EVENT类型为mysql5.6中的RowsQueryLogEvent，用于记录RBR模式下insert/update/delete中执行的sql.

mariadb10

mariadb10主要是基于mysql5.6的原型，类型定义基本没啥变化，大体上都保持兼容(沿用了mysql5.6中TIMESTAMP2等新的时间类型和新的log_event类型)

主要的变化：

1. QueryLogEvent增加了status变量.    

• Q_HRNOW  用于记录毫秒的精度，枚举值下标为128

协议解析的时候，需要处理Q_HRNOW，需要跳过3字节的数据.  

ps.  mysql5.6后，新增了Q_MICROSECONDS来支持mariaDb中Q_HRNOW的毫秒精度的功能.  

2. binlog事件的变化

1.MARIA_EVENTS_BEGIN= 160,  
2.  /* New Maria event numbers start from here */  
3.  ANNOTATE_ROWS_EVENT= 160,  
4.  /* 
5.    Binlog checkpoint event. Used for XA crash recovery on the master, not used 
6.    in replication. 
7.    A binlog checkpoint event specifies a binlog file such that XA crash 
8.    recovery can start from that file - and it is guaranteed to find all XIDs 
9.    that are prepared in storage engines but not yet committed. 
10.  */  
11.  BINLOG_CHECKPOINT_EVENT= 161,  
12.  /* 
13.    Gtid event. For global transaction ID, used to start a new event group, 
14.    instead of the old BEGIN query event, and also to mark stand-alone 
15.    events. 
16.  */  
17.  GTID_EVENT= 162,  
18.  /* 
19.    Gtid list event. Logged at the start of every binlog, to record the 
20.    current replication state. This consists of the last GTID seen for 
21.    each replication domain. 
22.  */  
23.  GTID_LIST_EVENT= 163,  
24.  
25.  /* Add new MariaDB events here - right above this comment!  */  
26.  
27.  ENUM_END_EVENT /* end marker */  

MARIA_EVENTS_BEGIN= 160,
  /* New Maria event numbers start from here */
  ANNOTATE_ROWS_EVENT= 160,
  /*
    Binlog checkpoint event. Used for XA crash recovery on the master, not used
    in replication.
    A binlog checkpoint event specifies a binlog file such that XA crash
    recovery can start from that file - and it is guaranteed to find all XIDs
    that are prepared in storage engines but not yet committed.
  */
  BINLOG_CHECKPOINT_EVENT= 161,
  /*
    Gtid event. For global transaction ID, used to start a new event group,
    instead of the old BEGIN query event, and also to mark stand-alone
    events.
  */
  GTID_EVENT= 162,
  /*
    Gtid list event. Logged at the start of every binlog, to record the
    current replication state. This consists of the last GTID seen for
    each replication domain.
  */
  GTID_LIST_EVENT= 163,

  /* Add new MariaDB events here - right above this comment!  */

  ENUM_END_EVENT /* end marker */

 新增了mariadb自己的gtid处理

使用注意

1.  AnnotateRowsEvent使用

•  mariadb需要在my.cnf中设置binlog_annotate_row_events = true，开启记录annotate事件
• canal在发送COM_BINLOG_DUMP指令中需要设置binlog_flags |= BINLOG_SEND_ANNOTATE_ROWS_EVENT，不然mariadb默认不会发送AnnotateRowsEvent，而是以空的QueryLogEvent来代替.

2.  新增的binlog类型使用

• canal需要设置当前session变量
  
  
  

  1.SET @mariadb_slave_capability='" + LogEvent.MARIA_SLAVE_CAPABILITY_MINE + "'"