MySQL Bugs: #96369: Contribution by Facebook: Add long-query-time to mysqldump

Bug #96369	Contribution by Facebook: Add long-query-time to mysqldump
Submitted:	29 Jul 2019 21:11	Modified:	25 May 2022 11:58
Reporter:	FBContrib Admin	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: mysqldump Command-line Client	Severity:	S3 (Non-critical)
Version:	8.0.13	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Background innformation provided by Facebook:
The slow log currently contains noise from mysqldump because their queries are usually longer running. This adds an option to mysqldump to specify long_query_time as a session variable to avoid this problem.

Specifying --long_query_time=0 for mysqldump means using the server's value instead of explicitly setting it. It does not set long_query_time to 0.

Use case:

We often enable the slow query log to capture slow queries and find applications that are causing problems on the server. However, mysqldump often trips these slow query log timers because it needs to perform a full table scan. This option allows mysqldump to skip logging to the slow query log.

https://github.com/mysql/mysql-server 
Patch on top of 8.0.13: https://github.com/mysql/mysql-server/commit/e4924f36486f971f8a04252e01c803457a2c72f7

How to repeat:
See description

Suggested fix:
See contribution code attached

Add long-query-time to mysqldump 
(*) This code is contributed under the Facebook agreement

Contribution: fb_patch_114.txt (text/plain), 5.61 KiB.

Posted by developer:
 
Added bug number to changelog for WL #13447:

        A new mysqldump option
        --mysqld-long-query-time lets you set a
        custom value of the long_query_time system
        variable for mysqldump’s session. Use the
        new option to increase the elapsed time allowed for
        mysqldump’s queries before they are written
        to the slow query log file, in order to avoid unnecessary
        logging. Thanks to Facebook for the contribution.

Bug number published