数据库篇-错误日志

1. 错误日志

1.1 : 作用

记录启动\关闭\日常运行过程中,状态信息,警告,错误

1.2 : 错误日志配置

默认就是开启的: /数据路径下/hostname.err

手工设定:

Master [(none)]>select @@log_error;
vim /etc/my.cnf
log_error=/var/log/mysql.log
log_timestamps=system

重启生效

show variables like 'log_error';

1.3 : 日志内容查看

主要关注[ERROR],看上下文

2. binlog(binary logs):二进制日志

2.1 : 作用

(1)备份恢复必须依赖二进制日志
(2)主从环境必须依赖二进制日志

2.2 : binlog配置 (5.7必须加server_id)

注意：MySQL默认是没有开启二进制日志的。
基础参数查看:

开关:
[(none)]>select @@log_bin;
日志路径及名字
[(none)]>select @@log_bin_basename;
服务ID号:
[(none)]>select @@server_id;
二进制日志格式:
[(none)]>select @@binlog_format;
双一标准之二:
[(none)]>select @@sync_binlog;

2.2.1 : 创建日志目录

mkdir /data/binlog
chown -R mysql.mysql /data/binlog

2.2.2 : 修改配置文件

vim /etc/my.cnf
server_id=6   ----->5.6中，单机可以不需要此参数              
log_bin=/data/binlog/mysql-bin
binlog_format=row

2.2.3 : 重启数据库生效

[root@db01 mysql]# /etc/init.d/mysqld restart

2.2.4 : 参数说明

server_id=3306 
主要是在主从复制过程中必须要加的,但是在5.7版本中,要用以下参数(log_bin),开启binlog日志,即使是单机也是必加的
log_bin=/data/binlog/mysql-bin
(1)开启二进制日志功能
(2)设置二进制日志目录及名称前缀
binlog_format=row
binlog的记录格式??

2.3 : binlog记录了什么?

2.3.1 : 引入

binlog是SQL层的功能。记录的是变更SQL语句，不记录查询语句。

2.3.2 : 记录SQL语句种类

DDL ：原封不动的记录当前DDL(statement语句方式)。
DCL ：原封不动的记录当前DCL(statement语句方式)。
DML ：只记录已经提交的事务DML

2.3.3 : DML三种记录方式

binlog_format（binlog的记录格式）参数影响

（1）statement（5.6默认）SBR(statement based replication) 语句模式原封不动的记录当前DML。
（2）ROW (5.7 默认值) RBR(ROW based replication) 记录数据行的变化(用户看不懂，需要工具分析)
（3）mixed（混合）MBR(mixed based replication)模式：以上两种模式的混合

2.4 : event（事件）是什么?

2.4.1 : 事件的简介

二进制日志的最小记录单元

对于DDL,DCL,一个语句就是一个event
对于DML语句来讲:只记录已提交的事务。

例如以下列子,就被分为了4个event

begin;      120  - 340
DML1        340  - 460
DML2        460  - 550
commit;     550  - 760

2.4.2 : event的组成

三部分构成:

(1) 事件的开始标识
(2) 事件内容
(3) 事件的结束标识

Position:
开始标识: at 194
结束标识: end_log_pos 254

194? 254?
某个事件在binlog中的相对位置号

位置号的作用是什么？
为了方便我们截取事件

2.5 日志文件查看

2.5.1 : 查看日志的开启情况

log_bin参数设置的路径,可以找到二进制日志

Master [(none)]>show variables like '%log_bin%';
+---------------------------------+------------------------------+
| Variable_name                   | Value                        |
+---------------------------------+------------------------------+
| log_bin                         | ON                           |
| log_bin_basename                | /data/binlog/mysql-bin       |
| log_bin_index                   | /data/binlog/mysql-bin.index |
| log_bin_trust_function_creators | OFF                          |
| log_bin_use_v1_row_events       | OFF                          |
| sql_log_bin                     | ON                           |
+---------------------------------+------------------------------+
6 rows in set (0.01 sec)

2.5.2 : 查看一共多少个binlog

Master [(none)]>show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000001 |       154 |
+------------------+-----------+
1 row in set (0.01 sec)

Master [(none)]>flush logs;
Query OK, 0 rows affected (0.03 sec)

Master [(none)]>flush logs;
Query OK, 0 rows affected (0.01 sec)

Master [(none)]>show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000001 |       201 |
| mysql-bin.000002 |       201 |
| mysql-bin.000003 |       154 |
+------------------+-----------+
3 rows in set (0.00 sec)

Master [(none)]>

2.5.3 : 查看mysql正在使用的日志文件

Master [(none)]>show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---*斜体样式*---------------+----------+--------------+------------------+-------------------+
| mysql-bin.000003 |      154 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
Master [(none)]>

file: 当前MySQL正在使用的文件名
Position：最后一个事件的结束位置号

2.6 : 日志内容查看

2.6.1 : event查看

Master [binlog]>show binlog events in 'mysql-bin.000003';
+------------------+-----+----------------+-----------+-------------+----------------------------------------+
| Log_name         | Pos | Event_type     | Server_id | End_log_pos | Info                                   |
+------------------+-----+----------------+-----------+-------------+----------------------------------------+
| mysql-bin.000003 |   4 | Format_desc    |         6 |         123 | Server ver: 5.7.20-log, Binlog ver: 4  |
| mysql-bin.000003 | 123 | Previous_gtids |         6 |         154 |                                        |
| mysql-bin.000003 | 154 | Anonymous_Gtid |         6 |         219 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'   |
| mysql-bin.000003 | 219 | Query          |         6 |         319 | create database binlog                 |
| mysql-bin.000003 | 319 | Anonymous_Gtid |         6 |         384 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'   |
| mysql-bin.000003 | 384 | Query          |         6 |         486 | use `binlog`; create table t1 (id int) |
+------------------+-----+----------------+-----------+-------------+----------------------------------------+

Log_name：binlog文件名
Pos：开始的position
Event_type：事件类型
Format_desc：格式描述，每一个日志文件的第一个事件，多用户没有意义，

MySQL识别binlog必要信息

Server_id：mysql服务号标识
End_log_pos：事件的结束位置号
Info：事件内容

补充:

SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
[root@db01 binlog]# mysql -e "show binlog events in 'mysql-bin.000004'" |grep drop

2.6.2 : binlog文件内容详细查看

mysqlbinlog /data/mysql/mysql-bin.000006
mysqlbinlog --base64-output=decode-rows -vvv /data/binlog/mysql-bin.000003
mysqlbinlog  -d binlog /data/binlog/mysql-bin.000003
[root@db01 binlog]# mysqlbinlog --start-datetime='2019-05-06 17:00:00' --stop-datetime='2019-05-06 17:01:00'  /data/binlog/mysql-bin.000004

2.7 : 基于Position号进行日志截取

核心就是找截取的起点和终点

--start-position=321
--stop-position=513
 mysqlbinlog --start-position=219 --stop-position=1347 /data/binlog/mysql-bin.000003 >/tmp/bin.sql

案例: 使用binlog日志进行数据恢复

模拟:

1. 
[(none)]>create database binlog charset utf8;
2. 
[(none)]>use binlog;
[binlog]>create table t1(id int);
3. 
[binlog]>insert into t1 values(1);
[binlog]>commit;
[binlog]>insert into t1 values(2);
[binlog]>commit;
[binlog]>insert into t1 values(3);
[binlog]>commit;
4. 
[binlog]>drop database binlog;

恢复:

[(none)]>show master status ;
[(none)]>show binlog events in 'mysql-bin.000004';
[root@db01 binlog]# mysqlbinlog --start-position=1227 --stop-position=2342 /data/binlog/mysql-bin.000004 >/tmp/bin.sql
[(none)]>set sql_Log_bin=0;
[(none)]>source /tmp/bin.sql

2.8 : binlog日志的GTID新特性

2.8.1 : GTID 介绍

5.6 版本新加的特性,5.7中做了加强
5.6 中不开启,没有这个功能.
5.7 中的GTID,即使不开也会有自动生成

SET @@SESSION.GTID_NEXT= 'ANONYMOUS'

2.8.2 : GTID(Global Transaction ID)

是对于一个已提交事务的编号，并且是一个全局唯一的编号。

它的官方定义如下：

GTID = source_id ：transaction_id
7E11FA47-31CA-19E1-9E56-C43AA21293967:29

重要参数介绍：

vim /etc/my.cnf
gtid-mode=on
enforce-gtid-consistency=true
systemctl restart mysqld

Master [(none)]>create database gtid charset utf8;
Query OK, 1 row affected (0.01 sec)

Master [(none)]>show master status ;
+------------------+----------+--------------+------------------+----------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                      |
+------------------+----------+--------------+------------------+----------------------------------------+
| mysql-bin.000004 |      326 |              |                  | dff98809-55c3-11e9-a58b-000c2928f5dd:1 |
+------------------+----------+--------------+------------------+----------------------------------------+
1 row in set (0.00 sec)

Master [(none)]>use gtid
Database changed
Master [gtid]>create table t1 (id int);
Query OK, 0 rows affected (0.01 sec)

Master [gtid]>show master status ;
+------------------+----------+--------------+------------------+------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000004 |      489 |              |                  | dff98809-55c3-11e9-a58b-000c2928f5dd:1-2 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

Master [gtid]>create table t2 (id int);
Query OK, 0 rows affected (0.01 sec)

Master [gtid]>create table t3 (id int);
Query OK, 0 rows affected (0.02 sec)

Master [gtid]>show master status ;
+------------------+----------+--------------+------------------+------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000004 |      815 |              |                  | dff98809-55c3-11e9-a58b-000c2928f5dd:1-4 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

Master [gtid]>begin;
Query OK, 0 rows affected (0.00 sec)

Master [gtid]>insert into t1 values(1);
Query OK, 1 row affected (0.00 sec)

Master [gtid]>commit;
Query OK, 0 rows affected (0.00 sec)

Master [gtid]>show master status ;
+------------------+----------+--------------+------------------+------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000004 |     1068 |              |                  | dff98809-55c3-11e9-a58b-000c2928f5dd:1-5 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

Master [gtid]>begin;
Query OK, 0 rows affected (0.00 sec)

Master [gtid]>insert into t2 values(1);
Query OK, 1 row affected (0.00 sec)

Master [gtid]>commit;
Query OK, 0 rows affected (0.01 sec)

Master [gtid]>show master status ;
+------------------+----------+--------------+------------------+------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000004 |     1321 |              |                  | dff98809-55c3-11e9-a58b-000c2928f5dd:1-6 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

2.8.3 : 基于GTID进行查看binlog

具备GTID后,截取查看某些事务日志:

--include-gtids  #包含的 GTID节点
--exclude-gtids  #去除的 GTID节点
mysqlbinlog --include-gtids='dff98809-55c3-11e9-a58b-000c2928f5dd:1-6' --exclude-gtids='dff98809-55c3-11e9-a58b-000c2928f5dd:4'  /data/binlog/mysql-bin.000004

2.8.4 : GTID的幂等性

开启GTID后,MySQL恢复Binlog时,重复GTID的事务不会再执行了
就想恢复?怎么办?

--skip-gtids  #忽略 GTID 的一致性特性
mysqlbinlog --include-gtids='3ca79ab5-3e4d-11e9-a709-000c293b577e:4' /data/binlog/mysql-bin.000004 /data/binlog/mysql-bin.000004
set sql_log_bin=0;
source /tmp/binlog.sql #恢复数据
set sql_log_bin=1;

2.9 : 使用二进制日志恢复数据案例

2.9.1 : 故障环境介绍

创建了一个库 db, 导入了表t1 ,t1表中录入了很多数据
一个开发人员,drop database db;

没有备份,日志都在.怎么恢复?

思路: 找到建库语句到删库之前所有的日志,进行恢复.(开启了GTID模式)

故障案例模拟:

(0) drop database if exists db ;
(1) create database db charset utf8;     
(2) use db;
(3) create table t1 (id int);
(4) insert into t1 values(1),(2),(3);
(5) insert into t1 values(4),(5),(6);
(6) commit
(7) update t1 set id=30 where id=3;
(8) commit;
(9) delete from t1 where id=4;
(10)commit;
(11)insert into t1 values(7),(8),(9);
(12)commit;
(13)drop database db;
========================
drop database if exists db ;
create database db charset utf8; 
use db;
create table t1 (id int);
insert into t1 values(1),(2),(3);
insert into t1 values(4),(5),(6);
commit;
update t1 set id=30 where id=3;
commit;
delete from t1 where id=4;
commit;
insert into t1 values(7),(8),(9);
commit;
drop database db;
=======

运行以上语句，模拟故障场景
需求：将数据库恢复到以下状态（提示第9步和第13步是误操作，其他都是正常操作）

2.9.2 : 恢复过程(无GTID时的恢复)

1.查看当前使用的 binlog文件

oldguo [db]>show master status ;
+------------------+----------+--------------+------------------+-------------------+

| File            | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+------------------+----------+--------------+------------------+-------------------+

| mysql-bin.000006 |    1873 |              |                  |                  |

+------------------+----------+--------------+------------------+-------------------+

2.查看事件：

第一段：

| mysql-bin.000006 |  813 | Query      |        1 |        907 | use `db`; create table t1 (id int)                  |

| mysql-bin.000006 |  907 | Query      |        1 |        977 | BEGIN                                              |

| mysql-bin.000006 |  977 | Table_map  |        1 |        1020 | table_id: 77 (db.t1)                                |

| mysql-bin.000006 | 1020 | Write_rows  |        1 |        1070 | table_id: 77 flags: STMT_END_F                      |

| mysql-bin.000006 | 1070 | Table_map  |        1 |        1113 | table_id: 77 (db.t1)                                |

| mysql-bin.000006 | 1113 | Write_rows  |        1 |        1163 | table_id: 77 flags: STMT_END_F                      |

| mysql-bin.000006 | 1163 | Xid        |        1 |        1194 | COMMIT /* xid=74 */                                |

| mysql-bin.000006 | 1194 | Query      |        1 |        1264 | BEGIN                                              |

| mysql-bin.000006 | 1264 | Table_map  |        1 |        1307 | table_id: 77 (db.t1)                                |

| mysql-bin.000006 | 1307 | Update_rows |        1 |        1353 | table_id: 77 flags: STMT_END_F                      |

| mysql-bin.000006 | 1353 | Xid        |        1 |        1384 | COMMIT /* xid=77 */   

mysqlbinlog --start-position=813 --stop-position=1384 /data/mysql/mysql-bin.000006 >/tmp/bin1.sql

第二段:


| mysql-bin.000006 | 1568 | Query      |        1 |        1638 | BEGIN                                              |

| mysql-bin.000006 | 1638 | Table_map  |        1 |        1681 | table_id: 77 (db.t1)                                |

| mysql-bin.000006 | 1681 | Write_rows  |        1 |        1731 | table_id: 77 flags: STMT_END_F                      |

| mysql-bin.000006 | 1731 | Xid        |        1 |        1762 | COMMIT /* xid=81 */ 

mysqlbinlog --start-position=1568 --stop-position=1762 /data/mysql/mysql-bin.000006 >/tmp/bin2.sql

恢复:

set sql_log_bin=0;
source /tmp/bin1.sql
source /tmp/bin2.sql
set sql_log_bin=1;
oldguo [db]>select * from t1;

+------+

| id  |

+------+

|    1 |

|    2 |

|  30 |

|    4 |

|    5 |

|    6 |

|    7 |

|    8 |

|    9 |

2.9.3 : 有GTID的恢复

1.截取

mysqlbinlog --skip-gtids --include-gtids='3ca79ab5-3e4d-11e9-a709-000c293b577e:7-12' mysql-bin.000004> /tmp/bin.sql

2.恢复

set sql_log_bin=0;
source /tmp/bin.sql

2.10 : 二进制日志其他操作

2.10.1 : 自动清理日志

show variables like '%expire%';
expire_logs_days  0

自动清理时间,是要按照全备周期+1

set global expire_logs_days=8;
永久生效:
my.cnf
expire_logs_days=15;

企业建议,至少保留两个全备周期+1 的 binlog

2.10.2 : 手工清理

PURGE BINARY LOGS BEFORE now() - INTERVAL 3 day;
PURGE BINARY LOGS TO 'mysql-bin.000010';

注意:不要手工 rm binlog文件

1. my.cnf binlog关闭掉,启动数据库
2.把数据库关闭,开启binlog,启动数据库

删除所有binlog,并从000001开始重新记录日志

2.10.3 : 日志是怎么滚动

flush logs;

重启mysql也会自动滚动一个新的日志文件达到1G大小(max_binlog_size)

| max_binlog_size                          | 1073741824

备份时,加入参数也可以自动滚动

原文地址