pt工具主从一致性检查并修复以及版本3.0.4的版本缺点

 　　pt-table-checksum和pt-table-sync分别检验master-slave的数据不一致并修复。

1、本次测试环境

 1 [root@172-16-3-190 we_ops_admin]# cat /etc/redhat-release 
 2 CentOS release 6.8 (Final)
 3 [root@172-16-3-190 we_ops_admin]# /opt/app/mysql_3309/bin/mysqladmin --version
 4 /opt/app/mysql_3309/bin/mysqladmin  Ver 8.42 Distrib 5.6.20-68.0, for Linux on x86_64
 5 [root@172-16-3-190 we_ops_admin]# pt-table-checksum --version
 6 pt-table-checksum 3.0.4
 7 
 8 master1:172.16.3.190 basedir：/opt/app/mysql_3309/  datadir:/opt/app/mysql_3309/data port：3309 
 9 slave1:172.16.3.189 basedir：/opt/app/mysql_3309/  datadir:/opt/app/mysql_3309/data port：3309
10 master&slave：binlog_format=mixed

2、

 1 ----测试表aa结构
 2 CREATE TABLE `aa` (
 3   `aa` varchar(1) DEFAULT '',
 4   `bb` varchar(1) DEFAULT NULL,
 5   `id` int(11) NOT NULL,
 6   PRIMARY KEY (`id`)
 7 ) ENGINE=InnoDB DEFAULT CHARSET=utf8
 8 
 9 ----master上表数据
10 mysql> select * from aa;
11 +------+------+----+
12 | aa   | bb   | id |
13 +------+------+----+
14 | 1    | 1    |  1 |
15 | 2    | 2    |  2 |
16 | 5    | 2    |  5 |
17 +------+------+----+
18 3 rows in set (0.00 sec)
19 
20 ----slave上表数据
21 mysql> select * from aa;
22 +------+------+----+
23 | aa   | bb   | id |
24 +------+------+----+
25 | 2    | 2    |  2 |
26 | 4    | 4    |  4 |
27 | 5    | 5    |  5 |
28 +------+------+----+
29 3 rows in set (0.00 sec)

3、开始检测差异

1）创建一个用户，可以访问master和slave，master上执行如下的创建用户命令

　构造master-slave的差异环境，slave同步master数据后，人为修改slave数据使得不一致。

1 grant all privileges on *.* to 'checksums'@'172.16.%.%' identified by 'checksums'
2 Query OK, 0 rows affected (0.00 sec)

2）pt-table-checksum检测差异，并写入差异到checksums表中，master上执行

1 [root@172-16-3-190 we_ops_admin]# /usr/bin/pt-table-checksum --create-replicate-table --replicate=ceshi.checksums --nocheck-replication-filters --nocheck-binlog-format --recursion-method=processlist --databases=ceshi --user=checksums --password=checksums -h172.16.3.190 --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309
2             TS ERRORS  DIFFS    ROWS  CHUNKS SKIPPED    TIME TABLE
3 01-30T10:26:44      0      0        3      1      0  0.042 ceshi.aa

pt-table-checksum 3.0.4的bug，功能缺乏，binlog_format格式非statement格式检测不出来差异

  DIFFS=0表示没有差异数据。实际上主从数据不一致，我们已经加入了参数--nocheck-binlog-format，这里却没有检测出来。为什么没有检测出来呢？

 pt-table-checksum针对的binlog_format=statement的格式，根据pt-table-checksum的原理，它在执行的时候，没有将会话级别的binlog_format=statement设置成功，那我们只能手动将动态参数binlog_format设置为statement模式。

  只有在statement格式下才能进行，因为两边要计算CRC32，计算完后再把主上的master_crc、master_cnt更新到从库，最后在从库对比master和this相关列，也就是说从库不会去计算所谓的CRC32，它直接完整copy主库的checksums的所有内容。pt-table-checksum 3.0.4在执行时缺少SET@@binlog_format='STATEMENT'，建议不要使用。

  有一种很挫的方法，仅仅是为了看差异结果(生产环境勿用)，执行pt-table-checksum前，在主上 set global binlog_format='STATEMENT'。

1 master上执行
2 mysql> set @@global.binlog_format=statement;
3 Query OK, 0 rows affected (0.00 sec)
4 
5 slave上执行
6 mysql> set @@global.binlog_format=statement;
7 Query OK, 0 rows affected (0.00 sec)

master上再次执行，发现DIFFS的值终于为1，表示已经检测到master-slave数据的不一致了

1 [root@172-16-3-190 we_ops_admin]# /usr/bin/pt-table-checksum --create-replicate-table --replicate=ceshi.checksums --nocheck-replication-filters --nocheck-binlog-format --recursion-method=processlist --databases=ceshi --user=checksums --password=checksums -h172.16.3.190 --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309
2             TS ERRORS  DIFFS    ROWS  CHUNKS SKIPPED    TIME TABLE
3 01-30T11:02:15      0      1        3      1      0  0.026 ceshi.aa

4、pt-table-sync修复master-slave数据不一致，master和slave都可以进行修复命令的执行

1）master上执行，--print打印出修复的sql语句。参数--sync-to-master参数在master上执行必须有，否则打印不出差异sql。

[root@172-16-3-190 we_ops_admin]# pt-table-sync --sync-to-master --replicate=ceshi.checksums -h172.16.3.190 --user=checksums --password=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 h=172.16.3.189,u=checksums,p=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 --print  
DELETE FROM `ceshi`.`aa` WHERE `id`='4' LIMIT 1 /*percona-toolkit src_db:ceshi src_tbl:aa src_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.190,p=...,u=checksums dst_db:ceshi dst_tbl:aa dst_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.189,p=...,u=checksums lock:1 transaction:1 changing_src:ceshi.checksums replicate:ceshi.checksums bidirectional:0 pid:13528 user:root host:172-16-3-190*/;
REPLACE INTO `ceshi`.`aa`(`aa`, `bb`, `id`) VALUES ('1', '1', '1') /*percona-toolkit src_db:ceshi src_tbl:aa src_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.190,p=...,u=checksums dst_db:ceshi dst_tbl:aa dst_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.189,p=...,u=checksums lock:1 transaction:1 changing_src:ceshi.checksums replicate:ceshi.checksums bidirectional:0 pid:13528 user:root host:172-16-3-190*/;
REPLACE INTO `ceshi`.`aa`(`aa`, `bb`, `id`) VALUES ('5', '2', '5') /*percona-toolkit src_db:ceshi src_tbl:aa src_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.190,p=...,u=checksums dst_db:ceshi dst_tbl:aa dst_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.189,p=...,u=checksums lock:1 transaction:1 changing_src:ceshi.checksums replicate:ceshi.checksums bidirectional:0 pid:13528 user:root host:172-16-3-190*/;

　slave上再次构造差异并执行修复命令　

 1 ---slave上执行
 2 mysql> update aa set id = 4 where aa = 5;
 3 Query OK, 1 row affected (0.00 sec)
 4 Rows matched: 1  Changed: 1  Warnings: 0
 5 
 6 ----master上执行检测
 7 [root@172-16-3-190 we_ops_admin]# /usr/bin/pt-table-checksum --create-replicate-table --replicate=ceshi.checksums --nocheck-replication-filters --nocheck-binlog-format --recursion-method=processlist --databases=ceshi --user=checksums --password=checksums -h172.16.3.190 --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309
 8 
 9 # A software update is available:
10             TS ERRORS  DIFFS     ROWS  CHUNKS SKIPPED    TIME TABLE
11 01-30T15:12:27      0      1        3       1       0   0.025 ceshi.aa
12 
13 ----slave上执行数据修复
14 [root@172-16-3-189 we_ops_admin]#  pt-table-sync --sync-to-master --replicate=ceshi.checksums -h172.16.3.190 --user=checksums --password=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 h=172.16.3.189,u=checksums,p=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 --print  
15 DELETE FROM `ceshi`.`aa` WHERE `id`='4' LIMIT 1 /*percona-toolkit src_db:ceshi src_tbl:aa src_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.190,p=...,u=checksums dst_db:ceshi dst_tbl:aa dst_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.189,p=...,u=checksums lock:1 transaction:1 changing_src:ceshi.checksums replicate:ceshi.checksums bidirectional:0 pid:23321 user:root host:172-16-3-189*/;
16 REPLACE INTO `ceshi`.`aa`(`aa`, `bb`, `id`) VALUES ('5', '2', '5') /*percona-toolkit src_db:ceshi src_tbl:aa src_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.190,p=...,u=checksums dst_db:ceshi dst_tbl:aa dst_dsn:P=3309,S=/opt/app/mysql_3309/tmp/mysql.sock,h=172.16.3.189,p=...,u=checksums lock:1 transaction:1 changing_src:ceshi.checksums replicate:ceshi.checksums bidirectional:0 pid:23321 user:root host:172-16-3-189*/;
17 
18 [root@172-16-3-189 we_ops_admin]#  pt-table-sync --sync-to-master --replicate=ceshi.checksums -h172.16.3.190 --user=checksums --password=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 h=172.16.3.189,u=checksums,p=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 --execute
19 
20 [root@172-16-3-189 we_ops_admin]# 3309.sh 
21 Warning: Using a password on the command line interface can be insecure.
22 Welcome to the MySQL monitor.  Commands end with ; or \g.
23 Your MySQL connection id is 223
24 Server version: 5.6.20-68.0-log Percona Server (GPL), Release 68.0, Revision 656
25 
26 Copyright (c) 2009-2014 Percona LLC and/or its affiliates
27 Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
28 
29 Oracle is a registered trademark of Oracle Corporation and/or its
30 affiliates. Other names may be trademarks of their respective
31 owners.
32 
33 Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
34 
35 mysql> select * from aa;
36 ERROR 1046 (3D000): No database selected
37 mysql> use ceshi;
38 Reading table information for completion of table and column names
39 You can turn off this feature to get a quicker startup with -A
40 
41 Database changed
42 mysql> select * from aa;
43 +------+------+----+
44 | aa  | bb  | id |
45 +------+------+----+
46 | 1    | 1    |  1 |
47 | 2    | 2    |  2 |
48 | 5    | 2    |  5 |
49 +------+------+----+
50 3 rows in set (0.00 sec)

2）--execute执行修复语句

1 [root@172-16-3-190 we_ops_admin]# pt-table-sync --sync-to-master --replicate=ceshi.checksums -h172.16.3.190 --user=checksums --password=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 h=172.16.3.189,u=checksums,p=checksums --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309 --execute

3）验证master和slave数据不一致性是否修复，经检验数据一致

 1 ----master上表aa数据
 2 mysql> select * from ceshi.aa;
 3 +------+------+----+
 4 | aa  | bb  | id |
 5 +------+------+----+
 6 | 1    | 1    |  1 |
 7 | 2    | 2    |  2 |
 8 | 5    | 2    |  5 |
 9 +------+------+----+
10 3 rows in set (0.00 sec)
11 
12 ----slave上表aa数据
13 mysql> select * from ceshi.aa;
14 +------+------+----+
15 | aa  | bb  | id |
16 +------+------+----+
17 | 1    | 1    |  1 |
18 | 2    | 2    |  2 |
19 | 5    | 2    |  5 |
20 +------+------+----+
21 3 rows in set (0.00 sec)

再次利用工具运行，检测master-slave数据一致性

1 [root@172-16-3-190 we_ops_admin]# /usr/bin/pt-table-checksum --create-replicate-table --replicate=ceshi.checksums --nocheck-replication-filters --nocheck-binlog-format --recursion-method=processlist --databases=ceshi --user=checksums --password=checksums -h172.16.3.190 --socket=/opt/app/mysql_3309/tmp/mysql.sock --port=3309
2             TS ERRORS  DIFFS    ROWS  CHUNKS SKIPPED    TIME TABLE
3 01-30T14:50:43      0      0        3      1      0  0.038 ceshi.aa