二进制日志-记录了什么

二进制日志的作用是记录数据库的更改,然后用于复制和PITR(即时恢复),对那些不改变数据库的语句则不会写入二进制日志,如果一些常用的查询语句等。二进制日志按照master上事务提交的顺序记录他们,取决于事务提交时间。我们通过具体的实例查看一下二进制日志具体的记录内容:

mysql> create database test;

Query OK, 1 row affected (0.00 sec)

mysql> drop database test;

Query OK, 0 rows affected (0.00 sec)

mysql> drop database oldboy;

Query OK, 0 rows affected (0.01 sec)

mysql> create database oldboy;

Query OK, 1 row affected (0.00 sec)

mysql> use oldboy;

Database changed

mysql> create table tbl (text TEXT);

Query OK, 0 rows affected (0.01 sec)

mysql> insert into tbl values(“hello,everyone!”);

Query OK, 1 row affected (0.01 sec)

mysql> select * from tbl;

+—————–+

| text|

+—————–+

| hello,everyone! |

+—————–+

1 row in set (0.00 sec)

mysql> flush logs;

Query OK, 0 rows affected (0.00 sec)

mysql>

flushlogs命令强制轮换(rotate)二进制文件,从而得到一个完整的二进制文件。下面我们使用show binlog events命令查看该文件。

mysql> show binlog events in ‘master-bin.000002’\G;

*************************** 1. row***************************

Log_name:master-bin.000002

Pos: 4

Event_type:Format_desc

Server_id: 165

End_log_pos: 120

Info: Serverver: 5.6.35-log, Binlog ver: 4

*************************** 2. row***************************

Log_name:master-bin.000002

Pos: 120

Event_type: Query

Server_id: 165

End_log_pos: 334

Info: GRANTREPLICATION SLAVE ON *.* TO ‘repl_user’@’192.168.10.%’ IDENTIFIED BY PASSWORD’*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9′

*************************** 3. row***************************

Log_name:master-bin.000002

Pos: 334

Event_type: Query

Server_id: 165

End_log_pos: 434

Info: createdatabase oldboy

*************************** 4. row***************************

Log_name:master-bin.000002

Pos: 434

Event_type: Query

Server_id: 165

End_log_pos: 528

Info: createdatabase test

*************************** 5. row***************************

Log_name:master-bin.000002

Pos: 528

Event_type: Query

Server_id: 165

End_log_pos: 613

Info: dropdatabase test

*************************** 6. row***************************

Log_name:master-bin.000002

Pos: 613

Event_type: Query

Server_id: 165

End_log_pos: 702

Info: dropdatabase oldboy

*************************** 7. row***************************

Log_name:master-bin.000002

Pos: 702

Event_type: Query

Server_id: 165

End_log_pos: 802

Info: createdatabase oldboy

*************************** 8. row ***************************

Log_name:master-bin.000002

Pos: 802

Event_type: Query

Server_id: 165

End_log_pos: 908

Info: use`oldboy`; create table tbl (text TEXT)

*************************** 9. row***************************

Log_name:master-bin.000002

Pos: 908

Event_type: Query

Server_id: 165

End_log_pos: 991

Info: BEGIN

*************************** 10. row***************************

Log_name:master-bin.000002

Pos: 991

Event_type: Query

Server_id: 165

End_log_pos: 1111

Info: use`oldboy`; insert into tbl values (“hello,everyone!”)

*************************** 11. row***************************

Log_name:master-bin.000002

Pos: 1111

Event_type: Xid

Server_id: 165

End_log_pos: 1142

Info: COMMIT/* xid=378 */

*************************** 12. row***************************

Log_name:master-bin.000002

Pos: 1142

Event_type: Rotate

Server_id: 165

End_log_pos: 1190

Info:master-bin.000003;pos=4

12 rows in set (0.01 sec)

ERROR:

No query specified

mysql>

Event_type:事件类型,Server_id:服务器ID, Log_name:存储事件的文件名,Pos:事件在文件中的开始位置,即事件的第一个字节。End_log_pos,事件在文件中的结束位置,也是下一个事件的开始位置。Info,事件信息的可读文本。

    原文作者:温东
    原文地址: https://www.jianshu.com/p/734b9e82746c
    本文转自网络文章,转载此文章仅为分享知识,如有侵权,请联系博主进行删除。
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