MySQL Bugs: #77619: InnoDB Online DDL limitations is missing some limitations

Bug #77619	InnoDB Online DDL limitations is missing some limitations
Submitted:	5 Jul 2015 8:47	Modified:	28 Jul 2015 20:04
Reporter:	Daniël van Eeden (OCA)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.6	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Page: http://dev.mysql.com/doc/refman/5.6/en/innodb-create-index-limitations.html

The most obvious limitation which is missing:
- It can cause serious slave lag (Bug #73196)

There are more:
- There is no I/O rate or CPU throttling
- It can't be paused (some OSC tools automatically pause if you stop a monitored slave).
- The progress reporting is minimal (there is sys.processlist.progress, but that requires more P_S instrumentation that the default).
- If aborted the ROLLBACK can be an expensive operation.
- It can cause the server to crash when there is no disk space left (Bug #77497), which can happen easily as it used @@tmpdir instead of @@datadir

How to repeat:
See description

Suggested fix:
Update page

Hello Daniël,

Thank you for the report.

Thanks,
Umesh

Posted by developer:
 
The "Limitations of Online DDL" section has been updated. Changes should appear on-line within 24 hours.

https://dev.mysql.com/doc/refman/5.6/en/innodb-create-index-limitations.html
https://dev.mysql.com/doc/refman/5.7/en/innodb-create-index-limitations.html

Thank you for the bug report.