1.使用Mysql慢查询日志配置
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查看慢查询日志是否开启 OFF关闭 ON开启
show variables like
'slow_query_log'
开启慢查询日志
set global slow_query_log = on
慢查询日志所存储的文件位置
show variables like
'slow_query_log_file'
设置慢查询日志位置
set global slow_query_log_file =
'/var/lib/mysql/iZbp1akzlq26t30fbsdwh7Z-slow.log'
是否吧没有使用索引的sql记录到慢查询日志当中 PFF关闭 ON开启
show variables like
'log_queries_not_using_indexes'
设置吧没有使用索引的sql记录添加到慢查询日志当中
set global log_queries_not_using_indexes = on;
查看long_query_time设置的时间
show variables like
'long_query_time'
;
超过多少秒之后的查询记录到慢查询日志当中
set [session|global] long_query_time =
1
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2.慢查询日志存储格式
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-- 执行sql时间
# Time:
2018
-
06
-26T07:
23
:
35
.892991Z
-- 执行SQL的主机信息
# User
@Host
: root[root] @ localhost [] Id:
387088
-- SQL的执行信息
# Query_time:
0.000155
Lock_time:
0.000057
Rows_sent:
12
Rows_examined:
31
-- SQL执行时间
SET timestamp=
1529997815
;
-- SQL内容
SELECT `key`,`value` FROM `yp_setti
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3.慢查询日志的分析工具 mysqldumpslow
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[root
@iZbp1akzlq26t30fbsdwh7Z
mysql] # mysqldumpslow -h
Option h requires an argument
ERROR: bad option
# 最简单的使用方式 mysqldumpslow 慢查询日志目录
Usage: mysqldumpslow [ OPTS... ] [ LOGS... ]
Parse and summarize the MySQL slow query log. Options are
--verbose verbose
--debug debug
--help write
this
text to standard output
-v verbose
-d debug
# -s参数 通过什么方式来排序
-s ORDER what to sort by (al, at, ar, c, l, r, t),
'at'
is
default
al: average lock time # 根据锁定时间
ar: average rows sent # 根据返回行数
at: average query time # 根据返回时间
c: count
l: lock time
r: rows sent
t: query time
-r reverse the sort order (largest last instead of first)
# -t 查看前多少条日志
-t NUM just show the top n queries
-a don
't abstract all numbers to N and strings to '
S'
-n NUM
abstract
numbers with at least n digits within names
-g PATTERN grep: only consider stmts that include
this
string
-h HOSTNAME hostname of db server
for
*-slow.log filename (can be wildcard),
default
is
'*'
, i.e. match all
-i NAME name of server instance (
if
using mysql.server startup script)
-l don't subtract lock time from total time
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4.mysqldumpslow 分析结果
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[root
@iZbp1akzlq26t30fbsdwh7Z
mysql]# mysqldumpslow /var/lib/mysql/iZbp1akzlq26t30fbsdwh7Z-slow.log -t
2
-s al
Reading mysql slow query log from /var/lib/mysql/iZbp1akzlq26t30fbsdwh7Z-slow.log
-- count 执行次数
-- time 执行时间
-- lock 锁定时间
-- rows 返回条数
-- root[root]
@localhost
通过那个用户执行的
Count:
5
Time=
0
.00s (0s) Lock=
0
.01s (0s) Rows=
5.0
(
25
), root[root]
@localhost
SHOW COLUMNS FROM `yp_area`
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