MySQL Slow query log

First, open the slow query log

1. Query slow query time default 10 seconds

 like "Long_query_time"

2. Query slow query log file address

 like "%slow%"

3. If the slow query log is not turned on, configure the item under My.ini [MYSQLD] and restart the MYSQLD service.

How MySQL is set less than or equal to version 5.5

#慢查询日志文件地址log-slow-queries = "E:/phpstudy/mysql/long_query_logs/buexplain-slow.log" #慢查询时间 (units in seconds), SQL that is greater than this time is logged to the slow query log file. long_query_time=0.5

How MySQL is set to be greater than or equal to version 5.6

#开启慢查询 1 or on means on, 0 or off to turn off slow_query_log=on #慢查询日志文件地址slow_query_log_file = "e:/phpstudy/mysql/long_query_logs/ Buexplain-slow.log "#慢查询时间 (in seconds), SQL that is greater than that time is logged to the slow query log file. long_query_time=0.5

4. Test Slow Query

SELECT 1

5. Check the number of slow queries

 like ' %slow% '

Second, slow query log analysis

# time:151001 19:06:58# [email protected]: root[root] @ localhost [127.0.0.1]# query_time:1.000057  lock_time:0.0000 XX rows_sent:1  rows_examined:0set timestamp=1443697618;select sleep (1);

First line: Execution time
Second line: Execute user
Third line (important):
Query_time SQL execution time, the longer the more slowly
Lock_time Waiting for table lock time during the MySQL server phase (not in the storage engine phase)
Rows_sent the number of rows returned by the query
rows_examined the number of rows checked by the query

Row four: Executed SQL

The tools for analyzing processing logs are:

1.mysqldumpslow perl script provided by the official

2.mysqlsla is a log analysis tool launched by hackmysql.com

3.pt-query-digest a Perl script

RELATED links:

http://www.zrwm.com/?p=2668

http://blog.csdn.net/a600423444/article/details/6854289

Iii. Summary

Do not turn on Log-queries-not-using-indexes no index query logging function, it affects the main slow query log view.

MySQL Slow query log