MySQL 二进制日志(Binary Log)

    同大多数关系型数据库一样,日志文件是MySQL数据库的重要组成部分。MySQL有几种不同的日志文件,通常包括错误日志文件,二进制日志,通用日志,慢查询日志,等等。这些日志可以帮助我们定位mysqld内部发生的事件,数据库性能故障,记录数据的变更历史,用户恢复数据库等等。二进制日志,也叫binary log,是MySQL Server中最为重要的日志之一,本文主要描述二进制日志。

 

1、MySQL日志文件系统的组成
   a、错误日志:记录启动、运行或停止mysqld时出现的问题。
   b、通用日志:记录建立的客户端连接和执行的语句。
   c、更新日志:记录更改数据的语句。该日志在MySQL 5.1中已不再使用。
   d、二进制日志:记录所有更改数据的语句。还用于复制。
   e、慢查询日志:记录所有执行时间超过long_query_time秒的所有查询或不使用索引的查询。
   f、Innodb日志:innodb redo log
 
   缺省情况下,所有日志创建于mysqld数据目录中。
   可以通过刷新日志,来强制mysqld来关闭和重新打开日志文件(或者在某些情况下切换到一个新的日志)。
   当你执行一个FLUSH LOGS语句或执行mysqladmin flush-logs或mysqladmin refresh时,则日志被老化。
   对于存在MySQL复制的情形下,从复制服务器将维护更多日志文件,被称为接替日志。

 

2、二进制日志(Binary log)
  a、它包含的内容及作用如下:
    包含了所有更新了数据或者已经潜在更新了数据(比如没有匹配任何行的一个DELETE)
    包含关于每个更新数据库(DML)的语句的执行时间信息
    不包含没有修改任何数据的语句,如果需要启用该选项,需要开启通用日志功能
    主要目的是尽可能的将数据库恢复到数据库故障点,因为二进制日志包含备份后进行的所有更新
    用于在主复制服务器上记录所有将发送给从服务器的语句
    启用该选项数据库性能降低1%,但保障数据库完整性,对于重要数据库值得以性能换完整。有些类似于oracle开启归档模式。
  
  b、开启二进制日志的方法及属性
    使用--log-bin[=file_name]选项或在配置文件中指定log-bin启动时,mysqld写入包含所有更新数据的SQL命令的日志文件。
    对于未给出file_name值, 默认名为-bin后面所跟的主机名。
    在未指定绝对路径的情形下,缺省位置保存在数据目录下。
    每个二进制日志名会添加一个数字扩展名用于日志老化,因此不支持自定义的扩展名,会被mysql数字扩展名动态替换。
    若当前的日志大小达到max_binlog_size,则自动创建新的二进制日志。
    对于大的事务,二进制日志会超过max_binlog_size设定的值。也即是事务仅仅写入一个二进制日志。
    由是可知,二进制日志文件大小接近,其size不是完全相等,这点不同于oracle。
    二进制日志文件会有一个对应二进制日志索引文件,该文件包含所有的二进制日志,其文件名与二进制日志相同,扩展名为.index
    二进制索引文件通过--log-bin-index[=file_name]选项来指定
    RESET MASTER语句将删除所有二进制日志文件,这将影响到从库。也可以用PURGE MASTER LOGS只删除部分二进制文件。
  

3、二进制日志相关演示

a、启用二进制日志
--当前环境
root@localhost[(none)]> show variables like ‘%version%‘;
+-------------------------+------------------------------+
| Variable_name           | Value                        |
+-------------------------+------------------------------+
| innodb_version          | 5.5.39                       |
| protocol_version        | 10                           |
| slave_type_conversions  |                              |
| version                 | 5.5.39                       |
| version_comment         | MySQL Community Server (GPL) |
| version_compile_machine | x86_64                       |
| version_compile_os      | Linux                        |
+-------------------------+------------------------------+

root@localhost[(none)]> show variables like ‘%log_bin%‘;
+---------------------------------+-------+
| Variable_name                   | Value |
+---------------------------------+-------+
| log_bin                         | OFF   | --该参数用于设定是否启用二进制日志
| log_bin_trust_function_creators | OFF   |
| sql_log_bin                     | ON    |
+---------------------------------+-------+

--以下为binary log相关参数
root@localhost[(none)]> show variables like ‘%binlog%‘;
+-----------------------------------------+----------------------+
| Variable_name                           | Value                |
+-----------------------------------------+----------------------+
| binlog_cache_size                       | 32768                |
| binlog_direct_non_transactional_updates | OFF                  |
| binlog_format                           | STATEMENT            |
| binlog_stmt_cache_size                  | 32768                |
| innodb_locks_unsafe_for_binlog          | OFF                  |
| max_binlog_cache_size                   | 18446744073709547520 |
| max_binlog_size                         | 1073741824           |
| max_binlog_stmt_cache_size              | 18446744073709547520 |
| sync_binlog                             | 0                    |
+-----------------------------------------+----------------------+

--当前mysql服务器数据文件的缺省位置
root@localhost[(none)]> show variables like ‘%datadir%‘;
+---------------+-----------------+
| Variable_name | Value           |
+---------------+-----------------+
| datadir       | /var/lib/mysql/ |
+---------------+-----------------+

--停止mysql服务器
suse11b:~ # service mysql stop
Shutting down MySQL....                                               done

--编辑my.cnf来设定binary log日志位置(注,配置二进制日志路径及文件名后,系统变量log_bin被自动置为on)
suse11b:~ # vi /etc/my.cnf
suse11b:~ # grep -v ^# /etc/my.cnf
[mysqld]
log-error=/tmp/suse11b.err
log_bin=/var/lib/mysql/binarylog/binlog
suse11b:~ # mkdir -p /var/lib/mysql/binarylog
suse11b:~ # chown -R mysql:mysql /var/lib/mysql/binarylog

suse11b:~ # /etc/init.d/mysql start
Starting MySQL..                                                      done
suse11b:~ # ls -hltr /var/lib/mysql/binarylog/*
-rw-rw---- 1 mysql mysql  39 Oct  3 13:41 /var/lib/mysql/binarylog/binlog.index  #索引文件
-rw-rw---- 1 mysql mysql 107 Oct  3 13:41 /var/lib/mysql/binarylog/binlog.000001 #日志文件


b、切换日志
suse11b:~ # mysql -uroot -pxxx
root@localhost[(none)]> flush logs;
Query OK, 0 rows affected (0.04 sec)

root@localhost[(none)]> system ls -hltr /var/lib/mysql/binarylog/*
-rw-rw---- 1 mysql mysql  78 Oct  3 13:43 /var/lib/mysql/binarylog/binlog.index
-rw-rw---- 1 mysql mysql 107 Oct  3 13:43 /var/lib/mysql/binarylog/binlog.000002  #切换后产生了000002
-rw-rw---- 1 mysql mysql 147 Oct  3 13:43 /var/lib/mysql/binarylog/binlog.000001

root@localhost[(none)]> system mysqladmin flush-logs    #使用mysqladmin命令行工具flush-logs方式切换日志
root@localhost[(none)]> system ls -hltr /var/lib/mysql/binarylog/*
-rw-rw---- 1 mysql mysql 147 Oct  3 13:43 /var/lib/mysql/binarylog/binlog.000001
-rw-rw---- 1 mysql mysql 117 Oct  3 13:45 /var/lib/mysql/binarylog/binlog.index
-rw-rw---- 1 mysql mysql 107 Oct  3 13:45 /var/lib/mysql/binarylog/binlog.000003  #切换后产生了000003
-rw-rw---- 1 mysql mysql 147 Oct  3 13:45 /var/lib/mysql/binarylog/binlog.000002

root@localhost[(none)]> system mysqladmin refresh       #使用mysqladmin命令行工具refresh方式切换日志
root@localhost[(none)]> system ls -hltr /var/lib/mysql/binarylog/*
-rw-rw---- 1 mysql mysql 147 Oct  3 13:43 /var/lib/mysql/binarylog/binlog.000001
-rw-rw---- 1 mysql mysql 147 Oct  3 13:45 /var/lib/mysql/binarylog/binlog.000002
-rw-rw---- 1 mysql mysql 156 Oct  3 13:46 /var/lib/mysql/binarylog/binlog.index
-rw-rw---- 1 mysql mysql 107 Oct  3 13:46 /var/lib/mysql/binarylog/binlog.000004  #切换后产生了000004
-rw-rw---- 1 mysql mysql 147 Oct  3 13:46 /var/lib/mysql/binarylog/binlog.000003 


c、模拟产生二进制日志及查看内容
root@localhost[(none)]> create database tempdb;
Query OK, 1 row affected (0.00 sec)

root@localhost[(none)]> use tempdb
Database changed
root@localhost[tempdb]> create table tb1(id smallint,val varchar(10));
Query OK, 0 rows affected (0.00 sec)

root@localhost[tempdb]> insert into tb1 values(1,‘jack‘);
Query OK, 1 row affected (0.01 sec)

root@localhost[tempdb]> system strings /var/lib/mysql/binarylog/binlog.000004
bin?8.T
5.5.39-log
z=.T
tempdb
create database tempdb
tempdb
create table tb1(id smallint,val varchar(10))
tempdb
BEGIN
tempdb
insert into tb1 values(1,‘jack‘)

root@localhost[tempdb]> system more /var/lib/mysql/binarylog/binlog.index
/var/lib/mysql/binarylog/binlog.000001
/var/lib/mysql/binarylog/binlog.000002
/var/lib/mysql/binarylog/binlog.000003
/var/lib/mysql/binarylog/binlog.000004

--使用命令行工具mysqlbinlog直接提取二进制日志的内容
root@localhost[tempdb]> system mysqlbinlog /var/lib/mysql/binarylog/binlog.000004
/*!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 4
#141003 13:46:39 server id 1  end_log_pos 107   Start: binlog v 4, server v 5.5.39-log created 141003 13:46:39
# Warning: this binlog is either in use or was not closed properly.
BINLOG ‘
PzguVA8BAAAAZwAAAGsAAAABAAQANS41LjM5LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAVAAEGggAAAAICAgCAA==
‘/*!*/;
# at 107
#141003 14:08:58 server id 1  end_log_pos 194   Query   thread_id=1     exec_time=0     error_code=0
SET TIMESTAMP=1412316538/*!*/;
SET @@session.pseudo_thread_id=1/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=0/*!*/;
SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
/*!\C utf8 *//*!*/;
SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=8/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
create database tempdb
/*!*/;
# at 194
#141003 14:09:36 server id 1  end_log_pos 304   Query   thread_id=1     exec_time=0     error_code=0
use `tempdb`/*!*/;
SET TIMESTAMP=1412316576/*!*/;
create table tb1(id smallint,val varchar(10))
/*!*/;
# at 304
#141003 14:09:56 server id 1  end_log_pos 374   Query   thread_id=1     exec_time=0     error_code=0
SET TIMESTAMP=1412316596/*!*/;
BEGIN
/*!*/;
# at 374
#141003 14:09:56 server id 1  end_log_pos 471   Query   thread_id=1     exec_time=0     error_code=0
SET TIMESTAMP=1412316596/*!*/;
insert into tb1 values(1,‘jack‘)
/*!*/;
# at 471
#141003 14:09:56 server id 1  end_log_pos 498   Xid = 25
COMMIT/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
--从以上的内容可以看出二进制日志记录了所有操作的DML语句及其开销,以及一些系统环境变量的信息。


d、管理二进制日志
--对于二进制日志,应尽可能保存在安全的位置,与数据分开存储  
--使用show binary logs获取二进制日志相关信息
root@localhost[(none)]> help show binary logs;
Name: ‘SHOW BINARY LOGS‘
Description:
Syntax:
SHOW BINARY LOGS
SHOW MASTER LOGS

Lists the binary log files on the server. This statement is used as
part of the procedure described in [HELP PURGE BINARY LOGS], that shows
how to determine which logs can be purged.

root@localhost[tempdb]> show binary logs;
+---------------+-----------+
| Log_name      | File_size |
+---------------+-----------+
| binlog.000001 |       147 |
| binlog.000002 |       147 |
| binlog.000003 |       147 |
| binlog.000004 |       498 |
+---------------+-----------+

show binlog events用于在二进制日志中显示事件。如果未指定‘log_name‘,则显示第一个二进制日志。
root@localhost[(none)]> help show binlog events;  --获取帮助信息
Name: ‘SHOW BINLOG EVENTS‘
Description:
Syntax:
SHOW BINLOG EVENTS
   [IN ‘log_name‘] [FROM pos] [LIMIT [offset,] row_count]

Shows the events in the binary log. If you do not specify ‘log_name‘,
the first binary log is displayed.

root@localhost[(none)]> show binlog events;
+---------------+-----+-------------+-----------+-------------+---------------------------------------+
| Log_name      | Pos | Event_type  | Server_id | End_log_pos | Info                                  |
+---------------+-----+-------------+-----------+-------------+---------------------------------------+
| binlog.000001 |   4 | Format_desc |         1 |         107 | Server ver: 5.5.39-log, Binlog ver: 4 |
| binlog.000001 | 107 | Rotate      |         1 |         147 | binlog.000002;pos=4                   |
+---------------+-----+-------------+-----------+-------------+---------------------------------------+

root@localhost[(none)]> show binlog events in ‘binlog.000005‘;  --binlog.000005不存在,所以报错
ERROR 1220 (HY000): Error when executing command SHOW BINLOG EVENTS: Could not find target log

--下面的这个查询中,前面执行的DML在这里均可以看到
root@localhost[tempdb]> show binlog events in ‘binlog.000004‘;
+---------------+-----+-------------+-----------+-------------+-------------------------------------------------------------+
| Log_name      | Pos | Event_type  | Server_id | End_log_pos | Info                                                        |
+---------------+-----+-------------+-----------+-------------+-------------------------------------------------------------+
| binlog.000004 |   4 | Format_desc |         1 |         107 | Server ver: 5.5.39-log, Binlog ver: 4                       |
| binlog.000004 | 107 | Query       |         1 |         194 | create database tempdb                                      |
| binlog.000004 | 194 | Query       |         1 |         304 | use `tempdb`; create table tb1(id smallint,val varchar(10)) |
| binlog.000004 | 304 | Query       |         1 |         374 | BEGIN                                                       |
| binlog.000004 | 374 | Query       |         1 |         471 | use `tempdb`; insert into tb1 values(1,‘jack‘)              |
| binlog.000004 | 471 | Xid         |         1 |         498 | COMMIT /* xid=25 */                                         |
+---------------+-----+-------------+-----------+-------------+-------------------------------------------------------------+

root@localhost[tempdb]> show binlog events in ‘binlog.000004‘ from 374;
+---------------+-----+------------+-----------+-------------+------------------------------------------------+
| Log_name      | Pos | Event_type | Server_id | End_log_pos | Info                                           |
+---------------+-----+------------+-----------+-------------+------------------------------------------------+
| binlog.000004 | 374 | Query      |         1 |         471 | use `tempdb`; insert into tb1 values(1,‘jack‘) |
| binlog.000004 | 471 | Xid        |         1 |         498 | COMMIT /* xid=25 */                            |
+---------------+-----+------------+-----------+-------------+------------------------------------------------+

root@localhost[tempdb]> show binlog events in ‘binlog.000004‘ from 374 limit 1;
+---------------+-----+------------+-----------+-------------+------------------------------------------------+
| Log_name      | Pos | Event_type | Server_id | End_log_pos | Info                                           |
+---------------+-----+------------+-----------+-------------+------------------------------------------------+
| binlog.000004 | 374 | Query      |         1 |         471 | use `tempdb`; insert into tb1 values(1,‘jack‘) |
+---------------+-----+------------+-----------+-------------+------------------------------------------------+


d、删除历史日志
--使用purge手动删除指定日志
--使用expire-log-days删除失效日志,设置变量expire_logs_days,删除超出这个变量保留期之前的所有日志被删除
--自动日志删除通常发生在服务器启动以及日志flush
--reset master方式
root@localhost[(none)]> help purge;
Name: ‘PURGE BINARY LOGS‘
Description:
Syntax:
PURGE { BINARY | MASTER } LOGS
    { TO ‘log_name‘ | BEFORE datetime_expr }

Examples:
PURGE BINARY LOGS TO ‘mysql-bin.010‘;
PURGE BINARY LOGS BEFORE ‘2008-04-02 22:46:26‘;

root@localhost[tempdb]> purge binary logs to ‘binlog.000003‘;
Query OK, 0 rows affected (0.12 sec)

root@localhost[tempdb]> show binary logs;
+---------------+-----------+
| Log_name      | File_size |
+---------------+-----------+
| binlog.000003 |       147 |
| binlog.000004 |       498 |
+---------------+-----------+

root@localhost[tempdb]> system ls -hltr /var/lib/mysql/binarylog/*
-rw-rw---- 1 mysql mysql 147 Oct  3 13:46 /var/lib/mysql/binarylog/binlog.000003
-rw-rw---- 1 mysql mysql 498 Oct  3 14:09 /var/lib/mysql/binarylog/binlog.000004
-rw-rw---- 1 mysql mysql  78 Oct  3 14:23 /var/lib/mysql/binarylog/binlog.index

--使用before子句purge日志,binlog.000003被删除
root@localhost[tempdb]> purge binary logs before ‘2014-10-03 14:09:56‘;
Query OK, 0 rows affected (0.02 sec)

root@localhost[tempdb]> show binary logs;
+---------------+-----------+
| Log_name      | File_size |
+---------------+-----------+
| binlog.000004 |       498 |
+---------------+-----------+

--Author: Leshami
--Blog  : http://blog.csdn.net/leshami
--重置所有日志
--reset master将删除在索引文件中列出所有的日志文件并重置索引文件,最后生成一个新的binlog文件。
--该操作之前先备份binlog至其它位置以备以后需要。
root@localhost[tempdb]> help reset master;
Name: ‘RESET MASTER‘
Description:
Syntax:
RESET MASTER

Deletes all binary log files listed in the index file, resets the
binary log index file to be empty, and creates a new binary log file.
This statement is intended to be used only when the master is started
for the first time.

root@localhost[tempdb]> reset master;
Query OK, 0 rows affected (0.13 sec)

root@localhost[tempdb]> show binary logs;
+---------------+-----------+
| Log_name      | File_size |
+---------------+-----------+
| binlog.000001 |       107 |  --reset之后,从000001开始生成全新空日志
+---------------+-----------+

--expire_log系统变量控制二进制日志自动删除的天数。默认值为0,表示“没有自动删除”。启动时和二进制日志循环时可能删除。
root@localhost[tempdb]> show variables like ‘expire_log%‘;
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| expire_logs_days | 0     |
+------------------+-------+

root@localhost[tempdb]> set expire_logs_days=7;   --提示次系统变量为全局变量
ERROR 1229 (HY000): Variable ‘expire_logs_days‘ is a GLOBAL variable and should be set with SET GLOBAL
root@localhost[tempdb]> set global expire_logs_days=7;  --设置
Query OK, 0 rows affected (0.01 sec)

root@localhost[tempdb]> select @@expire_logs_days;
+--------------------+
| @@expire_logs_days |
+--------------------+
|                  7 |
+--------------------+


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