慢查询日志分析(mysql)

时间:2023-03-08 16:02:56
慢查询日志分析(mysql)

开启慢查询日志之后,慢查询sql会被存到数据库系统表mysql.slow_log或是文件中,可参考。有两个工具可以帮助我们分析输出报告,分别是mysqldumpslow和pt-query-digest.

mysqldumpslow

mysqldumpslow是mysql自身提供的日志分析工具,一般在mysql的bin目录下

慢查询日志分析(mysql)

帮助信息

 $ mysqldumpslow.pl --help
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 ORDER what to sort by (al, at, ar, c, l, r, t), 'at' is default
al: average lock time
ar: average rows sent
at: average query time
c: count
l: lock time
r: rows sent
t: query time
-r reverse the sort order (largest last instead of first)
-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
 -s, 是表示按照何种方式排序
c: 访问计数 l: 锁定时间 r: 返回记录 t: 查询时间 al:平均锁定时间 ar:平均返回记录数 at:平均查询时间 -t, 是top n的意思,即为返回前面多少条的数据;
-g, 后边可以写一个正则匹配模式,大小写不敏感的; 比如:
得到返回记录集最多的10个SQL。
mysqldumpslow -s r -t 10 /database/mysql/mysql06_slow.log 得到访问次数最多的10个SQL
mysqldumpslow -s c -t 10 /database/mysql/mysql06_slow.log 得到按照时间排序的前10条里面含有左连接的查询语句。
mysqldumpslow -s t -t 10 -g “left join” /database/mysql/mysql06_slow.log 另外建议在使用这些命令时结合 | 和more 使用 ,否则有可能出现刷屏的情况。
mysqldumpslow -s r -t 20 /mysqldata/mysql/mysql06-slow.log | more

如果不能执行,可以先安装perl,然后通过perl mysqldumpslow xxx.log

pt-query-digest 参考

个人觉的pt-query-digest分析报告比mysqldumpslow好用。pt-query-digest可以不仅可以分析slowlog,还可以分析binlog,generallog等。

下载安装 https://www.percona.com/downloads/percona-toolkit/LATEST/

在windows下,下载tar.gz包,解压之后,使用perl命令运行

慢查询日志分析(mysql)

慢查询日志分析(mysql)

帮助信息

$ perl pt-query-digest --help
pt-query-digest analyzes MySQL queries from slow, general, and binary log files.
It can also analyze queries from C<SHOW PROCESSLIST> and MySQL protocol data
from tcpdump. By default, queries are grouped by fingerprint and reported in
descending order of query time (i.e. the slowest queries first). If no C<FILES>
are given, the tool reads C<STDIN>. The optional C<DSN> is used for certain
options like L<"--since"> and L<"--until">. For more details, please use the
--help option, or try 'perldoc pt-query-digest' for complete documentation. Usage: pt-query-digest [OPTIONS] [FILES] [DSN] Options: --ask-pass Prompt for a password when connecting to MySQL
--attribute-aliases=a List of attribute|alias,etc (default db|Schema)
--attribute-value-limit=i A sanity limit for attribute values (default 0)
--charset=s -A Default character set
--config=A Read this comma-separated list of config files;
if specified, this must be the first option on
the command line
--[no]continue-on-error Continue parsing even if there is an error (
default yes)
--[no]create-history-table Create the --history table if it does not exist (
default yes)
--[no]create-review-table Create the --review table if it does not exist (
default yes)
--daemonize Fork to the background and detach from the shell
--database=s -D Connect to this database
--defaults-file=s -F Only read mysql options from the given file
--embedded-attributes=a Two Perl regex patterns to capture pseudo-
attributes embedded in queries
--expected-range=a Explain items when there are more or fewer than
expected (default 5,10)
--explain=d Run EXPLAIN for the sample query with this DSN
and print results
--filter=s Discard events for which this Perl code doesn't
return true
--group-by=A Which attribute of the events to group by (
default fingerprint)
--help Show help and exit
--history=d Save metrics for each query class in the given
table. pt-query-digest saves query metrics (
query time, lock time, etc.) to this table so
you can see how query classes change over time
--host=s -h Connect to host
--ignore-attributes=a Do not aggregate these attributes (default arg,
cmd, insert_id, ip, port, Thread_id, timestamp,
exptime, flags, key, res, val, server_id,
offset, end_log_pos, Xid)
--inherit-attributes=a If missing, inherit these attributes from the
last event that had them (default db,ts)
--interval=f How frequently to poll the processlist, in
seconds (default .1)
--iterations=i How many times to iterate through the collect-
and-report cycle (default 1)
--limit=A Limit output to the given percentage or count (
default 95%:20)
--log=s Print all output to this file when daemonized
--order-by=A Sort events by this attribute and aggregate
function (default Query_time:sum)
--outliers=a Report outliers by attribute:percentile:count (
default Query_time:1:10)
--output=s How to format and print the query analysis
results (default report)
--password=s -p Password to use when connecting
--pid=s Create the given PID file
--port=i -P Port number to use for connection
--preserve-embedded-numbers Preserve numbers in database/table names when
fingerprinting queries
--processlist=d Poll this DSN's processlist for queries, with --
interval sleep between
--progress=a Print progress reports to STDERR (default time,
30)
--read-timeout=m Wait this long for an event from the input; 0 to
wait forever (default 0). Optional suffix s=
seconds, m=minutes, h=hours, d=days; if no
suffix, s is used.
--[no]report Print query analysis reports for each --group-by
attribute (default yes)
--report-all Report all queries, even ones that have been
reviewed
--report-format=A Print these sections of the query analysis
report (default rusage,date,hostname,files,
header,profile,query_report,prepared)
--report-histogram=s Chart the distribution of this attribute's
values (default Query_time)
--resume=s If specified, the tool writes the last file
offset, if there is one, to the given filename
--review=d Save query classes for later review, and don't
report already reviewed classes
--run-time=m How long to run for each --iterations. Optional
suffix s=seconds, m=minutes, h=hours, d=days; if
no suffix, s is used.
--run-time-mode=s Set what the value of --run-time operates on (
default clock)
--sample=i Filter out all but the first N occurrences of
each query
--set-vars=A Set the MySQL variables in this comma-separated
list of variable=value pairs
--show-all=H Show all values for these attributes
--since=s Parse only queries newer than this value (parse
queries since this date)
--slave-password=s Sets the password to be used to connect to the
slaves
--slave-user=s Sets the user to be used to connect to the slaves
--socket=s -S Socket file to use for connection
--timeline Show a timeline of events
--type=A The type of input to parse (default slowlog)
--until=s Parse only queries older than this value (parse
queries until this date)
--user=s -u User for login if not current user
--variations=A Report the number of variations in these
attributes' values
--version Show version and exit
--[no]version-check Check for the latest version of Percona Toolkit,
MySQL, and other programs (default yes)
--[no]vertical-format Output a trailing "\G" in the reported SQL
queries (default yes)
--watch-server=s This option tells pt-query-digest which server
IP address and port (like "10.0.0.1:3306") to
watch when parsing tcpdump (for --type tcpdump);
all other servers are ignored Option types: s=string, i=integer, f=float, h/H/a/A=comma-separated list, d=DSN, z=size, m=time Rules: This tool accepts additional command-line arguments. Refer to the SYNOPSIS and usage information for details. DSN syntax is key=value[,key=value...] Allowable DSN keys: KEY COPY MEANING
=== ==== =============================================
A yes Default character set
D yes Default database to use when connecting to MySQL
F yes Only read default options from the given file
P yes Port number to use for connection
S yes Socket file to use for connection
h yes Connect to host
p yes Password to use when connecting
t no The --review or --history table
u yes User for login if not current user If the DSN is a bareword, the word is treated as the 'h' key. Options and values after processing arguments: --ask-pass FALSE
--attribute-aliases db|Schema
--attribute-value-limit 0
--charset (No value)
--config /etc/percona-toolkit/percona-toolkit.conf,/etc/percona-toolkit/pt-query-digest.conf,/c/Users/Admin/.percona-toolkit.conf,/c/Users/Admin/.pt-query-digest.conf
--continue-on-error TRUE
--create-history-table TRUE
--create-review-table TRUE
--daemonize FALSE
--database (No value)
--defaults-file (No value)
--embedded-attributes (No value)
--expected-range 5,10
--explain (No value)
--filter (No value)
--group-by fingerprint
--help TRUE
--history (No value)
--host (No value)
--ignore-attributes arg,cmd,insert_id,ip,port,Thread_id,timestamp,exptime,flags,key,res,val,server_id,offset,end_log_pos,Xid
--inherit-attributes db,ts
--interval .1
--iterations 1
--limit 95%:20
--log (No value)
--order-by Query_time:sum
--outliers Query_time:1:10
--output report
--password (No value)
--pid (No value)
--port (No value)
--preserve-embedded-numbers FALSE
--processlist (No value)
--progress time,30
--read-timeout 0
--report TRUE
--report-all FALSE
--report-format rusage,date,hostname,files,header,profile,query_report,prepared
--report-histogram Query_time
--resume (No value)
--review (No value)
--run-time (No value)
--run-time-mode clock
--sample (No value)
--set-vars
--show-all
--since (No value)
--slave-password (No value)
--slave-user (No value)
--socket (No value)
--timeline FALSE
--type slowlog
--until (No value)
--user (No value)
--variations
--version FALSE
--version-check TRUE
--vertical-format TRUE
--watch-server (No value)
pt-query-digest [OPTIONS] [FILES] [DSN]
--create-review-table 当使用--review参数把分析结果输出到表中时,如果没有表就自动创建。
--create-history-table 当使用--history参数把分析结果输出到表中时,如果没有表就自动创建。
--filter 对输入的慢查询按指定的字符串进行匹配过滤后再进行分析
--limit 限制输出结果百分比或数量,默认值是20,即将最慢的20条语句输出,如果是50%则按总响应时间占比从大到小排序,输出到总和达到50%位置截止。
--host mysql服务器地址
--user mysql用户名
--password mysql用户密码
--history 将分析结果保存到表中,分析结果比较详细,下次再使用--history时,如果存在相同的语句,且查询所在的时间区间和历史表中的不同,则会记录到数据表中,可以通过查询同一CHECKSUM来比较某类型查询的历史变化。
--review 将分析结果保存到表中,这个分析只是对查询条件进行参数化,一个类型的查询一条记录,比较简单。当下次使用--review时,如果存在相同的语句分析,就不会记录到数据表中。
--output 分析结果输出类型,值可以是report(标准分析报告)、slowlog(Mysql slow log)、json、json-anon,一般使用report,以便于阅读。
--since 从什么时间开始分析,值为字符串,可以是指定的某个”yyyy-mm-dd [hh:mm:ss]”格式的时间点,也可以是简单的一个时间值:s(秒)、h(小时)、m(分钟)、d(天),如12h就表示从12小时前开始统计。
--until 截止时间,配合—since可以分析一段时间内的慢查询。

输出结果分析

分为三部分

第一部分 总体统计结果

overall:总共统计结果

time range:查询执行的时间范围

unique:唯一查询数量,即对查询条件进行参数化以后,总共有多少个不同的查询

total:总计

min:最小

max:最大

avg:平均

95%:把所有值从小到大排列,位置位于95%的那个数,这个数一般最具参考价值

median:中位数,把所有值从小到大排列,位置位于中间那个数

# 该工具执行日志分析的用户时间,系统时间,物理内存占用大小,虚拟内存占用大小
# 343ms user time, 78ms system time, 0 rss, 0 vsz
# 工具执行时间
# Current date: Thu Mar 29 15:51:38 2018
# 运行分析工具的主机名
# Hostname: NB2015041602
# 被分析的文件名
# Files: /d/xampp/mysql/data/NB2015041602-slow.log
# 语句总数量,唯一的语句数量,QPS,并发数
# Overall: 5 total, 3 unique, 0.00 QPS, 0.05x concurrency ________________
# 日志记录的时间范围
# Time range: 2018-03-28 14:02:06 to 14:22:10
# 属性 总计 最小 最大 平均 95% 标准 中等
# Attribute total min max avg 95% stddev median
# ============ ======= ======= ======= ======= ======= ======= =======
# 语句执行时间
# Exec time 60s 10s 17s 12s 17s 3s 11s
# 锁占用时间
# Lock time 1ms 0 500us 200us 490us 240us 0
# 发送到客户端的行数
# Rows sent 50 10 10 10 10 0 10
# select语句扫描行数
# Rows examine 629.99k 45.43k 146.14k 126.00k 143.37k 39.57k 143.37k
# 查询的字符数
# Query size 2.81k 235 1.36k 575.40 1.33k 445.36 234.30

第二部分 查询分组统计结果

rank:所有语句的排序,默认按照查询时间降序排序,通过--order-by指定

query id:语句的id,(去掉多余空格和文本字符,计算hash值)

response:总的响应时间

time:该查询在本次分析中总的时间占比

calls:执行次数,即本次分析总共有多少条这种类型的查询语句

r/call:平均每次执行的响应时间

v/m:响应时间variance-to-mean的比率

item:查询对象

# Profile
# Rank Query ID Response time Calls R/Call V/M Item
# ==== ================== ============= ===== ======= ===== ==============
# 1 0x96112A601F7BCCC0 32.9042 55.0% 3 10.9681 0.01 SELECT affiliatemerchant_list user_list
# 2 0x70885F9703A0E38D 17.2162 28.8% 1 17.2162 0.00 SELECT normalmerchant merchant_mapping normalmerchant_addinfo merchant_search_filter affiliatemerchant_list user_list
# 3 0x43D8527285567FC4 9.7367 16.3% 1 9.7367 0.00 SELECT affiliatemerchant_list user_list affiliatemerchant_list user_list

第三部分 每一种查询的详细统计结果

id:查询的id号,和上面的query id对应

databases:数据库名

users:各个用户执行的次数(占比)

query_time_distribution:查询时间分布,长短体现区间占比

tables:查询中设计到的表

explain:sql语句

# Query 1: 0.00 QPS, 0.03x concurrency, ID 0x96112A601F7BCCC0 at byte 2647
# This item is included in the report because it matches --limit.
# Scores: V/M = 0.01
# Time range: 2018-03-28 14:03:31 to 14:19:54
# Attribute pct total min max avg 95% stddev median
# ============ === ======= ======= ======= ======= ======= ======= =======
# Count 60 3
# Exec time 54 33s 11s 11s 11s 11s 243ms 11s
# Lock time 50 500us 0 500us 166us 490us 231us 0
# Rows sent 60 30 10 10 10 10 0 10
# Rows examine 69 438.42k 146.14k 146.14k 146.14k 146.14k 0 146.14k
# Query size 24 707 235 236 235.67 234.30 0 234.30
# String:
# Databases database_base
# Hosts localhost
# Users root
# Query_time distribution
# 1us
# 10us
# 100us
# 1ms
# 10ms
# 100ms
# 1s
# 10s+ ################################################################
# Tables
# SHOW TABLE STATUS FROM `database_base` LIKE 'table_list1'\G
# SHOW CREATE TABLE `database_base`.`table_list1`\G
# SHOW TABLE STATUS FROM `database_base` LIKE 'user_list'\G
# SHOW CREATE TABLE `database_base`.`user_list`\G
# EXPLAIN /*!50100 PARTITIONS*/
select SQL_CALC_FOUND_ROWS al.*, ul.Alias as userName
FROM table_list1 al
LEFT JOIN user_list ul ON ul.ID = al.UserId
WHERE TRUE AND (al.SupportCountrys LIKE '%%') limit 80, 10\G

pt-query-digest用法示例(未测试)

直接分析慢查询文件
pt-query-digest slow.log > slow_report.log 分析最近12小时内的查询
pt-query-digest --since=12h slow.log > slow_report2.log 分析指定时间范围内的查询
pt-query-digest slow.log --since '2017-01-07 09:30:00' --until '2017-01-07 10:00:00'> > slow_report3.log 分析含有select语句的慢查询
pt-query-digest --filter '$event->{fingerprint} =~ m/^select/i' slow.log> slow_report4.log 针对某个用户的慢查询
pt-query-digest --filter '($event->{user} || "") =~ m/^root/i' slow.log> slow_report5.log 查询所有全表扫描或full join的慢查询
pt-query-digest --filter '(($event->{Full_scan} || "") eq "yes") ||(($event->{Full_join} || "") eq "yes")' slow.log> slow_report6.log 把查询保存到query_review表
pt-query-digest --user=root –password=abc123 --review h=localhost,D=test,t=query_review--create-review-table slow.log 把查询保存到query_history表
pt-query-digest --user=root –password=abc123 --review h=localhost,D=test,t=query_history--create-review-table slow.log_0001
pt-query-digest --user=root –password=abc123 --review h=localhost,D=test,t=query_history--create-review-table slow.log_0002 通过tcpdump抓取的tcp协议数据,然后分析
tcpdump -s 65535 -x -nn -q -tttt -i any -c 1000 port 3306 > mysql.tcp.txt
pt-query-digest --type tcpdump mysql.tcp.txt> slow_report9.log 分析biglog
mysqlbinlog mysql-bin.000093 > mysql-bin000093.sql
pt-query-digest --type=binlog mysql-bin000093.sql > slow_report10.log 分析general log
pt-query-digest --type=genlog localhost.log > slow_report11.log