percona-toolkit之pt-index-usage和pt-duplicate-key-checker详解

1> pt-index-usage：从慢查询日志中读取查询并分析它们如何使用索引。  (用来查找不常使用索引) ./pt-index-usage --help 打印报告 ./pt-index-usage  /mysqldata/mysqlslowlog/slowquery.log -h192.168.226.131 -uroot -p6yhn^YHN -decology [mysql@mysql bin]$ ./pt-index-usage  /mysqldata/mysqlslowlog/slowquery.log -h192.168.226.131 -uroot -p6yhn^YHN  DBD::mysql::db selectall_arrayref failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '/' at line 1 [for Statement "EXPLAIN SELECT IFNULL(SUM(INDEX_LENGTH),0) from information_schema.TABLES where ENGINE='InnoDB' */"] at ./pt-index-usage line 4598, <> line 1. DBD::mysql::db selectall_arrayref failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '/' at line 1 [for Statement "EXPLAIN SELECT IFNULL(SUM(DATA_LENGTH),0) from information_schema.TABLES where ENGINE='InnoDB' */"] at ./pt-index-usage line 4598, <> line 2. DBD::mysql::db selectall_arrayref failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '/' at line 1 [for Statement "EXPLAIN SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE' */"] at ./pt-index-usage line 4598, <> line 4. ALTER TABLE `test1`.`user` DROP KEY `idx_1`; -- type:non-unique 2>  pt-duplicate-key-checker检查数据库的重复索引 索引会更查询带来好处，但是过量的索引反而可能会使数据库的性能降低 ./pt-duplicate-key-checker --help 1> 表结构 [root@localhost][test1]> show index from user; +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | user  |          0 | PRIMARY  |            1 | id          | A         |     1042305 |     NULL | NULL   |      | BTREE      |         |               | | user  |          1 | idx_1    |            1 | id          | A         |     1042305 |     NULL | NULL   |      | BTREE      |         |               | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ 字段id有两个索引， [mysql@mysql bin]$ ./pt-duplicate-key-checker -uroot -p6yhn^YHN # ######################################################################## # test1.user                                                               # ######################################################################## # idx_1 is a duplicate of PRIMARY # Key definitions: #   KEY `idx_1` (`id`) #   PRIMARY KEY (`id`), # Column types: #         `id` int(11) not null auto_increment # To remove this duplicate index, execute: ALTER TABLE `test1`.`user` DROP INDEX `idx_1`; # ######################################################################## # Summary of indexes                                                       # ######################################################################## # Size Duplicate Indexes   4169220 # Total Duplicate Indexes  1 # Total Indexes            34