MySQL5.7使用pt-table-checksum检查主从数据一致性的测试讲解

安装环境：

os：linux 6.3 64bit

mysql: 5.7.21

percona-toolkit：2.2.18

安装过程：

#一些依赖包

yum install perl perl-dbi perl-dbd-mysql perl-io-socket-ssl perl-time-hires -y

#下载安装percona-toolkit

tar -xvf percona-toolkit_2.2.18.tar.gz

cd percona-toolkit-2.2.18/

perl makefile.pl

make

make test

make install

cp /usr/local/bin/pt* /bin/

测试步骤：

mysql为一主一从架构，在主库上安装toolkit，测试主从库是否一致。

1.建立测试帐号以及percona库

master server:

mysql> grant select,lock tables,process,super on *.* to  repl@'172.17.61.%';
query ok, 0 rows affected (0.14 sec)

mysql> grant select,create,drop,insert,delete,update,alter on percona.* to repl@'172.17.61.%';
query ok, 0 rows affected (0.07 sec)

mysql> insert into l5m.t2(c1,c2,c3) values(2,'eee',33);
query ok, 1 row affected (0.12 sec)

mysql> select * from l5m.t2;
+------+------+------+----+
| c1   | c2   | c3   | c4 |
+------+------+------+----+
|    1 | abc  |   22 | 33 |
|    2 | eee  |   33 | 34 |
+------+------+------+----+
2 rows in set (0.00 sec)

mysql> create database if not exists percona;
query ok, 1 row affected (0.17 sec)

2.准备测试数据，手动在slave用root帐户输入异步数据

master server:

mysql> select * from l5m.t2;
+------+------+------+----+
| c1   | c2   | c3   | c4 |
+------+------+------+----+
|    1 | abc  |   22 | 33 |
+------+------+------+----+
1 row in set (0.00 sec)

slave server:

mysql> insert into l5m.t2(c1,c2,c3) values(2,'eee',33);
query ok, 1 row affected (0.12 sec)

mysql> select * from l5m.t2;
+------+------+------+----+
| c1   | c2   | c3   | c4 |
+------+------+------+----+
|    1 | abc  |   22 | 33 |
|    2 | eee  |   33 | 34 |
+------+------+------+----+
2 rows in set (0.00 sec)

现在主从不一致了，从库多了一条数据

3.运行pt-table-checksum进行检查

[root@qht131 home]# pt-table-checksum h=172.17.61.131,u=repl,p='repl',p=3306 --databases=l5m --tables=t2
replica qht132 has binlog_format row which could cause pt-table-checksum to break replication.  please read "replicas using row-based replication" in the limitations section of the tool's documentation.  if you understand the risks, specify --no-check-binlog-format to disable this check.

提示需要指定no-check-binlog-format参数

[root@qht131 home]# pt-table-checksum h=172.17.61.131,u=repl,p='repl',p=3306 --databases=l5m --tables=t2 --no-check-binlog-format

# a software update is available:
#   * the current version for percona::toolkit is 3.0.5

            ts errors  diffs     rows  chunks skipped    time table
05-02t22:07:44      0      1        1       1       0   0.769 l5m.t2

pt-table-checksum第一次运行会在当前的库建立checksums表

来看一下这个表的数据：

master server:

mysql> select * from checksums\g
*************************** 1. row ***************************
            db: l5m
           tbl: t2
         chunk: 1
    chunk_time: 0.029503
   chunk_index: null
lower_boundary: null
upper_boundary: null
      this_crc: 5bbc5664
      this_cnt: 1
    master_crc: 5bbc5664
    master_cnt: 1
            ts: 2018-05-02 22:07:43
1 row in set (0.00 sec)

由于运行pt-table-checksum就是master server，所以在master的checksums表里显示的数据是一致的。

slave server:

mysql> select * from checksums\g
*************************** 1. row ***************************
            db: l5m
           tbl: t2
         chunk: 1
    chunk_time: 0.029503
   chunk_index: null
lower_boundary: null
upper_boundary: null
      this_crc: 2418ebee
      this_cnt: 2
    master_crc: 5bbc5664
    master_cnt: 1
            ts: 2018-05-02 22:07:43
1 row in set (0.00 sec)

这里显示了主从不一致的数据行数。

发现了不一致，需要借助另外一个工具pt-table-sync来同步主从数据了。