MySQL日志管理
MySQL日志简介
错误日志
默认是否开启:开启
默认路径及文件名:
- 源码和二进制安装:datadir/$hostname.err
- yum安装:/var/log/mysql.log
是否可以修改:可以
作用:查看MySQL启动时的报错找[Error]
如何修改:
## 查看错误日志路径
mysql> show variables like 'log_error';
+---------------+------------+
| Variable_name | Value |
+---------------+------------+
| log_error | ./db01.err |
+---------------+------------+
## 修改错误日志路径
[root@db01 ~]# vim /etc/my.cnf
[mysqld]
log_error=/tmp/log.txt
常规日志
默认是否开启:否
默认路径及文件名:datadir/$hostname.log
是否可以修改:可以
作用:记录MySQL的常规操作
如何修改:
## 查看常规日志是否开启和路径
mysql> show variables like '%gen%';
+------------------+----------------------------------+
| Variable_name | Value |
+------------------+----------------------------------+
| general_log | OFF |
| general_log_file | /application/mysql/data/db01.log |
+------------------+----------------------------------+
2 rows in set (0.00 sec)
### 常规日志开启(在企业中是不会开启该日志)
[root@db01 ~]# vim /etc/my.cnf
[mysqld]
general_log=1
general_log_file=/tmp/gen.lo
二进制日志(binlog)
默认是否开启:否
## 查看二进制日志是否开启
mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | ON |
+---------------+-------+
1 row in set (0.00 sec)
默认路径及文件名:datadir/xxx.000001
是否可以修改:可以
作用:
- 记录已结束的DML事务语句,并拆分为多个事件(event)来进行记录
- 记录所有DDL、DCL等语句
- 总之,二进制日志会记录所有对数据库、表发生修改的操作
如何修改:
## 以下修改方式为 mysql5.6
[root@db02 ~]# vim /etc/my.cnf
[mysqld]
log-bin=mysql-bin
[root@db02 ~]# vim /etc/my.cnf
[mysqld]
log-bin=/application/mysql/data/mysql-bin
[root@db02 ~]# vim /etc/my.cnf
[mysqld]
log-bin=/tmp/zls-bin
## MySQL5.7修改方式
MySQL5.7想要开binlog必须配置 server_id
server_id=1
log-bin=mysql-bin
mysql-bin.index:MySQL二进制日志binlog的索引文件,有几个binlog会记录几个binlog
二进制日志的工作模式
- statment:语句模式(MySQL5.6默认的工作模式)
mysql> show variables like 'binlog_format';
+---------------+-----------+
| Variable_name | Value |
+---------------+-----------+
| binlog_format | STATEMENT |
+---------------+-----------+
将所有的语句,记录在binlog中
优点:通俗易懂,占用磁盘空间小
缺点:不严谨
- row:行级模式(MySQL5.7的默认工作模式)
mysql[(none)]> show variables like 'binlog_format';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| binlog_format | ROW |
+---------------+-------+
将所有的语句及变化过程,记录在binlog中
优点:严谨
缺点:不易懂、占用磁盘空间大
- mixed:混合模式
语句模式和行级模式的混合模式
自己判断,什么时候只记录语句,什么时候记录语句和变化过程
没人用
工作模式如何修改
[root@db02 data]# vim /etc/my.cnf
[mysqld]
log-bin=/application/mysql/data/mysql-bin
binlog_format=row
如何查看二进制日志
## 查看默认语句模式
[root@db01 ~]# mysqlbinlog /application/mysql/data/mysql-bin.000001
## 查看行级模式
[root@db01 ~]# mysqlbinlog -vvv --base64-output=decode-row /application/mysql/data/mysql-bin.000001
## 库内查看当前有几个binlog日志及大小
mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 120 |
+------------------+-----------+
## 库内查看binlog日志的事件
mysql> mysql> show binlog events in 'mysql-bin.000001';
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
| mysql-bin.000001 | 4 | Format_desc | 1 | 120 | Server ver: 5.6.50-log, Binlog ver: 4 |
+------------------+-----+-------------+-----------+-------------+---------------------------------------+
事件介绍
- 在binlog中最小的记录单元为event
- 一个事务会被拆分成多个事件(event)
事件的特性
- 每个event都有一个开始位置(start position)和结束位置(stop position)。
- 所谓的位置就是event对整个二进制的文件的相对位置。
- 对于一个二进制日志中,前120个position是文件格式信息预留空间。
## mysql5.6
在MySQL5.6中,一个新的binlog起始位置点是120,120是系统信息预留空间
其实120,就是该文件的大小
143是空binlog,里面没有任何SQL语句执行
## mysql5.7
在MySQL5.7中,一个新的binlog起始位置点是154,154是系统信息预留空间
其实154,就是该文件的大小
177是空binlog,里面没有任何SQL语句执行
二进制日志数据故障恢复
## 查看binlog信息
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 120 | | | |
+------------------+----------+--------------+------------------+-------------------+
## 创建binlog数据库
mysql> create database binlog;
Query OK, 1 row affected (0.00 sec)
## 查看位置点
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 220 | | | |
+------------------+----------+--------------+------------------+-------------------+
## 创建一张表
mysql> use binlog
Database changed
mysql> create table tb1(id int);
Query OK, 0 rows affected (0.13 sec)
## 查看位置点
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 322 | | | |
+------------------+----------+--------------+------------------+-------------------+
## 插入数据
mysql> insert into tb1 values(1),(2),(3);
Query OK, 3 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 547 | | | |
+------------------+----------+--------------+------------------+-------------------+
mysql> commit;
Query OK, 0 rows affected (0.00 sec)
mysql> select * from tb1;
+------+
| id |
+------+
| 1 |
| 2 |
| 3 |
+------+
3 rows in set (0.00 sec)
mysql> update tb1 set id=10 where id=1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> commit;
Query OK, 0 rows affected (0.00 sec)
mysql> select * from tb1;
+------+
| id |
+------+
| 10 |
| 2 |
| 3 |
+------+
3 rows in set (0.00 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 770 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysql> delete from tb1 where id=2;
Query OK, 1 row affected (0.00 sec)
mysql> commit;
Query OK, 0 rows affected (0.00 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 988 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysql> select * from tb1;
+------+
| id |
+------+
| 10 |
| 3 |
+------+
## 删除表
mysql> drop table tb1;
Query OK, 0 rows affected (0.01 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 1108 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
## 删除库
mysql> drop database binlog;
Query OK, 0 rows affected (0.01 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 1197 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
如何恢复
## 1.查看binlog,找到起始位置点和结束位置点
[root@db01 ~]# mysqlbinlog -vvv --base64-output=decode-row /application/mysql/data/mysql-bin.000001
起始点:120
结束点:853
## 2.截取binlog
[root@db01 ~]# mysqlbinlog --start-position=120 --stop-position=853 /application/mysql/data/mysql-bin.000001 >/tmp/1.sql
## 3.导入截取出来的数据
[root@db01 ~]# mysql </tmp/1.sql -uroot -p
Enter password:
## 4.查询数据
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| binlog |
| linux50 |
| mysql |
| performance_schema |
| test |
| world |
| www |
+--------------------+
8 rows in set (0.00 sec)
mysql> use binlog
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+------------------+
| Tables_in_binlog |
+------------------+
| tb1 |
+------------------+
1 row in set (0.00 sec)
mysql> select * from tb1;
+------+
| id |
+------+
| 10 |
| 2 |
| 3 |
+------+
3 rows in set (0.00 sec)
此类方法存在问题
- 如果误删除一年之前创建的数据
解决方案:
全量备份,配合binlog的增量部分
- 用户使用数据是穿插使用的,binlog也不是一个库一个库记录的
解决方案:
只需要过滤出,被删除的数据库相关binlog中的sql语句
使用-d指定数据库截取binlog
[root@db01 data]# mysqlbinlog -d(指定) tb1(表名) -vvv --base64-output=decode-row mysql-bin.000001
刷新binlog
# 1.重启数据库会自动刷新binlog
# 2.当binlog大小达到1G的时候,会自动刷新出下一个binlog
# 3.手动执行 flush logs;
# 4.使用mysqladmin flush-log
[root@db04 data]# mysqladmin flush-log
# 5.使用mysqldump做备份时,可以刷新binlog
[root@db02 data]# mysqldump -A -F > /tmp/full.sql
删除binlog
原则:
在存储能力范围内,能保留多少binlog就保留多少binlog
## 1.根据存在时间删除日志
# 临时生效
mysql> set global expire_logs_days = 7;
Query OK, 0 rows affected (0.01 sec)
# 永久生效(不建议使用)
[root@db01 data]# vim /etc/my.cnf
[mysqld]
expire_logs_days = 7
## 2.删除指定时间段binlog
purge binary logs before now() - interval 3 day;
## 3.指定binlog名字删除,之前的binlog都删除
purge binary logs to 'mysql-bin.000010';
mysql[(none)]> purge binary logs to 'mysql-bin.000007';
## 4.重置binlog,删除所有binlog
mysql> reset master;
Query OK, 0 rows affected (0.01 sec)
mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 120 |
+------------------+-----------+
1 row in set (0.00 sec)
慢日志(慢查询日志)
默认是否开启:否
mysql> show variables like 'slow%';
+---------------------+---------------------------------------+
| Variable_name | Value |
+---------------------+---------------------------------------+
| slow_launch_time | 2 |
| slow_query_log | OFF |
| slow_query_log_file | /application/mysql/data/db01-slow.log |
+---------------------+---------------------------------------+
3 rows in set (0.00 sec)
默认路径及文件名:datadir/$hostname-slow.log
是否可以修改:可以
作用:
- 记录执行的比较慢的SQL语句
如何修改:
[root@db01 ~]# vim /etc/my.cnf
[mysqld]
# 指定是否开启慢查询日志
slow_query_log = 1
# 指定慢日志文件存放位置(默认在data)
slow_query_log_file=/application/mysql/data/slow.log
# 设定慢查询的阀值(默认10s)
long_query_time=0.05
# 不使用索引的SQL语句是否记录到慢查询日志
log_queries_not_using_indexes
# 查询检查返回少于该参数指定行的SQL不被记录到慢查询日志
min_examined_row_limit=1000(鸡肋)
查看慢查询日志
[root@db01 ~]# mysqldumpslow
-s:指定如何排序
c:按照记录次数
t:按照时间排序
r:按照返回记录排序
l:按照查询时间排序
ac:按照记录次数 倒序排序
at:按照时间排序 倒序排序
ar:按照返回记录 倒序排序
al:按照查询时间 倒序排序
-t:top N
-g:指定正则表达式
[root@db01 ~]# mysqldumpslow -s ar /application/mysql/data/slow.log
## 第三方percona公司提供
percona-tookit
pt-query-digest 慢查询日志名字