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

[5 Jul 2015 8:47] Daniël van Eeden
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
[6 Jul 2015 9:26] Umesh Shastry
Hello Daniël,

Thank you for the report.

Thanks,
Umesh
[28 Jul 2015 20:04] Daniel Price
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.