Bug #42663 Table Cache rules do not work in 5.1 (table_cache -> table_open_cache)
Submitted: 6 Feb 2009 19:10 Modified: 24 Feb 2009 18:11
Reporter: Andy Bang Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Enterprise Monitor: Advisors/Rules Severity:S3 (Non-critical)
Version:2.0.4.7141 OS:Any
Assigned to: Darren Oldag CPU Architecture:Any
Triage: Needs Triage: D2 (Serious)

[6 Feb 2009 19:10] Andy Bang
Description:
The "Table Cache Set Too Low For Startup" and "Table Cache Not Optimal" rules are not supported on MySQL 5.1 because the table_cache system variable has been deprecated and replaced with table_open_cache.

How to repeat:
Schedule the rules against a 5.0 server and you'll see they work.

Schedule them against a 5.1 server and you'll see you can't do it because table_cache is no longer reported via SHOW GLOBAL VARIABLES.
[6 Feb 2009 19:19] Andy Bang
Let's do a quick fix in the next 2.0 maintenance release, then think about the more comprehensive fix for 2.1.
[6 Feb 2009 21:49] Darren Oldag
providing a one-off forwards compatibile translation of table_cache to 
table_open_cache when table_cache is not supported and table_open_cache is.
when more of these broken mysql variables come up, we should examine
this 'fall forward' mechanism to see if it can be made more robust to
additional changes and externalized.

patch pushed to trunk.  merge to 2.0 is pending.
[6 Feb 2009 22:19] Darren Oldag
patch pushed to 2.0 maintenance tree.  ready for build and qa test.
[6 Feb 2009 23:38] Marcos Palacios
Verified fixed in service manager build 2.0.5.7144.
[9 Feb 2009 11:18] Tony Bedford
An entry was added to the 2.0.5 changelog:

The “Table Cache Set Too Low For Startup” and “Table Cache Not Optimal” rules were not supported on MySQL 5.1 because the table_cache system variable was deprecated and replaced with table_open_cache.
[24 Feb 2009 18:11] Marcos Palacios
Verified fixed in service manager build 2.1.0.1011.

Closing since it has already been tested in 2.0.5 (see previous comments).
[11 Dec 2009 20:51] Andy Bang
Related to Bug #49208