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mysql慢查询日志分析实例

发布时间：01/15 来源：浏览：关键词：

慢查询是一种非常不错的用来排除我们ＷＥＢ网站中所有sql执行的一个性能问题，我们可以通过慢查询分析找出性能差的sql查询了，下面我们来给各位在介绍mysql慢查询分析例子。

1、MySQL 慢查询日志分析

pt-query-digest分析慢查询日志
pt-query-digest –report slow.log

报告最近半个小时的慢查询：
pt-query-digest –report –since 1800s slow.log

报告一个时间段的慢查询：
pt-query-digest –report –since ‘2013-02-10 21:48:59′ –until ‘2013-02-16 02:33:50′ slow.log

报告只含select语句的慢查询:
pt-query-digest –filter ‘$event->{fingerprint} =~ m/^select/i’ slow.log

报告针对某个用户的慢查询:
pt-query-digest –filter ‘($event->{user} || “”) =~ m/^root/i’ slow.log

报告所有的全表扫描或full join的慢查询:
pt-query-digest –filter ‘(($event->{Full_scan} || “”) eq “yes”) || (($event->{Full_join} || “”) eq “yes”)’ slow.log

2、将慢查询日志的分析结果可视化

Query-Digest-UI

其实，这是一个非常简单和直接的工具，浏览和统计Mysql慢查询，基于AJAX的Web界面。
配置Query-Digest-UI：

下载：

wget https://nodeload.github.com/kormoc/Query-Digest-UI/zip/master
unzip Query-Digest-UI-master.zip
查询分析结果可视化步骤如下:

1)创建相关数据库表

?
-- install.sql
-- Create the database needed for the Query-Digest-UI
DROP DATABASE IF EXISTS slow_query_log;
CREATE DATABASE slow_query_log;
USE slow_query_log;

-- Create the global query review table
CREATE TABLE `global_query_review` (
`checksum` bigint(20) unsigned NOT NULL,
`fingerprint` text NOT NULL,
`sample` longtext NOT NULL,
`first_seen` datetime DEFAULT NULL,
`last_seen` datetime DEFAULT NULL,
`reviewed_by` varchar(20) DEFAULT NULL,
`reviewed_on` datetime DEFAULT NULL,
`comments` text,
`reviewed_status` varchar(24) DEFAULT NULL,
PRIMARY KEY (`checksum`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- Create the historical query review table
CREATE TABLE `global_query_review_history` (
`hostname_max` varchar(64) NOT NULL,
`db_max` varchar(64) DEFAULT NULL,
`checksum` bigint(20) unsigned NOT NULL,
`sample` longtext NOT NULL,
`ts_min` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`ts_max` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`ts_cnt` float DEFAULT NULL,
`Query_time_sum` float DEFAULT NULL,
`Query_time_min` float DEFAULT NULL,
`Query_time_max` float DEFAULT NULL,
`Query_time_pct_95` float DEFAULT NULL,
`Query_time_stddev` float DEFAULT NULL,
`Query_time_median` float DEFAULT NULL,
`Lock_time_sum` float DEFAULT NULL,
`Lock_time_min` float DEFAULT NULL,
`Lock_time_max` float DEFAULT NULL,
`Lock_time_pct_95` float DEFAULT NULL,
`Lock_time_stddev` float DEFAULT NULL,
`Lock_time_median` float DEFAULT NULL,
`Rows_sent_sum` float DEFAULT NULL,
`Rows_sent_min` float DEFAULT NULL,
`Rows_sent_max` float DEFAULT NULL,
`Rows_sent_pct_95` float DEFAULT NULL,
`Rows_sent_stddev` float DEFAULT NULL,
`Rows_sent_median` float DEFAULT NULL,
`Rows_examined_sum` float DEFAULT NULL,
`Rows_examined_min` float DEFAULT NULL,
`Rows_examined_max` float DEFAULT NULL,
`Rows_examined_pct_95` float DEFAULT NULL,
`Rows_examined_stddev` float DEFAULT NULL,
`Rows_examined_median` float DEFAULT NULL,
`Rows_affected_sum` float DEFAULT NULL,
`Rows_affected_min` float DEFAULT NULL,
`Rows_affected_max` float DEFAULT NULL,
`Rows_affected_pct_95` float DEFAULT NULL,
`Rows_affected_stddev` float DEFAULT NULL,
`Rows_affected_median` float DEFAULT NULL,
`Rows_read_sum` float DEFAULT NULL,
`Rows_read_min` float DEFAULT NULL,
`Rows_read_max` float DEFAULT NULL,
`Rows_read_pct_95` float DEFAULT NULL,
`Rows_read_stddev` float DEFAULT NULL,
`Rows_read_median` float DEFAULT NULL,
`Merge_passes_sum` float DEFAULT NULL,
`Merge_passes_min` float DEFAULT NULL,
`Merge_passes_max` float DEFAULT NULL,
`Merge_passes_pct_95` float DEFAULT NULL,
`Merge_passes_stddev` float DEFAULT NULL,
`Merge_passes_median` float DEFAULT NULL,
`InnoDB_IO_r_ops_min` float DEFAULT NULL,
`InnoDB_IO_r_ops_max` float DEFAULT NULL,
`InnoDB_IO_r_ops_pct_95` float DEFAULT NULL,
`InnoDB_IO_r_bytes_pct_95` float DEFAULT NULL,
`InnoDB_IO_r_bytes_stddev` float DEFAULT NULL,
`InnoDB_IO_r_bytes_median` float DEFAULT NULL,
`InnoDB_IO_r_wait_min` float DEFAULT NULL,
`InnoDB_IO_r_wait_max` float DEFAULT NULL,
`InnoDB_IO_r_wait_pct_95` float DEFAULT NULL,
`InnoDB_IO_r_ops_stddev` float DEFAULT NULL,
`InnoDB_IO_r_ops_median` float DEFAULT NULL,
`InnoDB_IO_r_bytes_min` float DEFAULT NULL,
`InnoDB_IO_r_bytes_max` float DEFAULT NULL,
`InnoDB_IO_r_wait_stddev` float DEFAULT NULL,
`InnoDB_IO_r_wait_median` float DEFAULT NULL,
`InnoDB_rec_lock_wait_min` float DEFAULT NULL,
`InnoDB_rec_lock_wait_max` float DEFAULT NULL,
`InnoDB_rec_lock_wait_pct_95` float DEFAULT NULL,
`InnoDB_rec_lock_wait_stddev` float DEFAULT NULL,
`InnoDB_rec_lock_wait_median` float DEFAULT NULL,
`InnoDB_queue_wait_min` float DEFAULT NULL,
`InnoDB_queue_wait_max` float DEFAULT NULL,
`InnoDB_queue_wait_pct_95` float DEFAULT NULL,
`InnoDB_queue_wait_stddev` float DEFAULT NULL,
`InnoDB_queue_wait_median` float DEFAULT NULL,
`InnoDB_pages_distinct_min` float DEFAULT NULL,
`InnoDB_pages_distinct_max` float DEFAULT NULL,
`InnoDB_pages_distinct_pct_95` float DEFAULT NULL,
`InnoDB_pages_distinct_stddev` float DEFAULT NULL,
`InnoDB_pages_distinct_median` float DEFAULT NULL,
`QC_Hit_cnt` float DEFAULT NULL,
`QC_Hit_sum` float DEFAULT NULL,
`Full_scan_cnt` float DEFAULT NULL,
`Full_scan_sum` float DEFAULT NULL,
`Full_join_cnt` float DEFAULT NULL,
`Full_join_sum` float DEFAULT NULL,
`Tmp_table_cnt` float DEFAULT NULL,
`Tmp_table_sum` float DEFAULT NULL,
`Filesort_cnt` float DEFAULT NULL,
`Filesort_sum` float DEFAULT NULL,
`Tmp_table_on_disk_cnt` float DEFAULT NULL,
`Tmp_table_on_disk_sum` float DEFAULT NULL,
`Filesort_on_disk_cnt` float DEFAULT NULL,
`Filesort_on_disk_sum` float DEFAULT NULL,
`Bytes_sum` float DEFAULT NULL,
`Bytes_min` float DEFAULT NULL,
`Bytes_max` float DEFAULT NULL,
`Bytes_pct_95` float DEFAULT NULL,
`Bytes_stddev` float DEFAULT NULL,
`Bytes_median` float DEFAULT NULL,
UNIQUE KEY `hostname_max` (`hostname_max`,`checksum`,`ts_min`,`ts_max`),
KEY `ts_min` (`ts_min`),
KEY `checksum` (`checksum`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2) 创建数据库账号

$ mysql -uroot -p -h 192.168.1.190 < install.sql
$ mysql -uroot -p -h 192.168.1.190 -e "grant ALL ON slow_query_log.* to 'slowlog'@'%' IDENTIFIED BY '123456';"

3) 配置Query-Digest-UI

修改数据库连接配置

cd Query-Digest-UI
cp config.php.example config.php
vi config.php
$reviewhost = array(
// Replace hostname and database in this setting
// use host=hostname;port=portnum if not the default port
    'dsn'           => 'mysql:host=192.168.1.190;port=3306;dbname=slow_query_log',
    'user'          => 'slowlog',
    'password'      => '123456',
// See http://www.percona.com/doc/percona-toolkit/2.1/pt-query-digest.html#cmdoption-pt-query-digest--review
    'review_table' => 'global_query_review',
// This table is optional. You don't need it, but you lose detailed stats
// Set to a blank string to disable
// See http://www.percona.com/doc/percona-toolkit/2.1/pt-query-digest.html#cmdoption-pt-query-digest--review-history
    'history_table' => 'global_query_review_history',
);

4)使用pt-query-digest分析日志并将分析结果导入数据库

pt-query-digest --user=slowlog \
--password=123456 \
--review h=192.168.1.190,D=slow_query_log,t=global_query_review \
--review-history h=192.168.1.190,D=slow_query_log,t=global_query_review_history\
--no-report --limit=0% \
--filter=" \$event->{Bytes} = length(\$event->{arg}) and \$event->{hostname}=\"$HOSTNAME\"" \
/usr/local/mysql/data/slow.log

MYSQL慢查询配置

1. 慢查询有什么用?

它能记录下所有执行超过long_query_time时间的SQL语句, 帮你找到执行慢的SQL, 方便我们对这些SQL进行优化.

2. 如何开启慢查询?

首先我们先查看MYSQL服务器的慢查询状态是否开启.执行如下命令: