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This article will explain in detail how to set up slow query support milliseconds in MySQL, and the content of the article is of high quality, so the editor will share it with you for reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

MySQL slow query supports millisecond setting

MySQL slow query itself does not support ms level (patch is required), but for versions of MySQL5.21+, the minimum long_query_time value is 0 (before 5.2.1, the minimum is 1s)

The unit is s. If you specify ms, its ms part will be ignored. In fact, this is already supported in millisecond level in disguise. For example, query time greater than 100ms will be recorded in slow log.

We can set up set global long_query_time=0.1

Test:

1. Set global long_query_time=0.1 directly. All queries with query time longer than 0.1s will be recorded in slow log. After setting, log out and log in again.

> set global long_query_time=0.1

Query OK, 0 rows affected (0.00 sec)

Mysql > exit

Bye

-bash-3.2 $

2, execute a query with a query of 0.2s to see if the query is recorded

Mysql > select sleep (0.2); www.2cto.com

+-+

| | sleep (0.2) |

+-+

| | 0 |

+-+

1 row in set (0.21 sec)

# administrator command: Quit

# Time: 120412 15:39:15

# User@Host: root [root] @ localhost []

# Query_time: 0.202244 Lock_time: 0.000000 Rows_sent: 1 Rows_examined: 0

SET timestamp=1334216355

Select sleep (0.2)

It can be seen that this query has been recorded in slow log

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