Bug #58332 Multiple buffer pool instances, only one is shown
Submitted: 19 Nov 2010 17:59 Modified: 10 Feb 2011 23:34
Reporter: Nicklas Westerlund (OCA) Email Updates:
Status: Closed Impact on me:
Category:MySQL Enterprise Monitor: Web Severity:S3 (Non-critical)
Version:2.3 OS:Any
Assigned to: Mark Leith CPU Architecture:Any

[19 Nov 2010 17:59] Nicklas Westerlund
When monitoring a 5.5 instance that is used in testing, and having enabled innodb_buffer_pool_instances to be >1, we still only get one graph for buffer pool info in MEM, which obviously only has only a subset of the total size

How to repeat:
set innodb_buffer_pool_instances > 1 and restart mysql, then check your graphs

Suggested fix:
monitor each instance independent of eachother, or perhaps also provide an aggregate
[19 Nov 2010 18:38] Mark Matthews
Hi Nicklas,

What do you have the "innodb_buffer_pool_size" set to? The variable "innodb_buffer_pool_instances" in 5.5.x essentially partitions the buffer pool into "innodb_buffer_pool_instances" equally-sized segments that take up "innodb_buffer_pool_size" memory. If your graph shows ""innodb_buffer_pool_size", then this is working as expected.
[19 Nov 2010 19:52] Nicklas Westerlund

I'm using advisor version

Just as a test I set the instances to be 10 and total buffer pool size to 1G. The graphs show ~100M (102 or so) as 'total size'.
[23 Nov 2010 12:33] Mark Leith
Verified as described
[24 Nov 2010 14:42] Calvin Sun
http://bugs.mysql.com/bug.php?id=58461 is opened to track InnoDB changes.
[29 Nov 2010 17:25] Enterprise Tools JIRA Robot
Gary Whizin writes: 
This is an issue with the innodb plugin in 5.1 as well and will go away when #58461 is fixed by the innodb team. Meanwhile, we'll add a note to the MEM readme to alert MEM users to this problem.
[9 Feb 2011 23:28] Enterprise Tools JIRA Robot
Bill Weber writes: 
verified showing the correct total buffer size with build
[10 Feb 2011 23:33] John Russell
Added to 2.3.2 change log:

The graph for the InnoDB buffer pool now reports correct totals when
innodb_buffer_pool_instances is set to a value greater than 0.
[10 Mar 2011 17:51] Valeriy Kravchuk
Bug #60418 was marked as a duplicate of this one.