Bug #67265 Warn about potential adverse effects of using INNODB_BUFFER_PAGE_LRU
Submitted: 16 Oct 2012 15:14 Modified: 29 Dec 2012 0:41
Reporter: Davi Arnaut (OCA) Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.5, 5.6 OS:Any
Assigned to: Bugs System CPU Architecture:Any
Tags: allocation, INNODB_BUFFER_PAGE_LRU, lock, Memory

[16 Oct 2012 15:14] Davi Arnaut 
Description:
Filling the INNODB_BUFFER_PAGE_LRU table might require more than 64 bytes times
the size of the LRU list. If the LRU is quite large, selecting from the table
will end up allocating a large contiguous block of memory, possibly causing an
out of memory condition depending on how much free memory is available. Also,
before the table is filled, the buffer pool lock is held for the entire duration
of the traversal of the LRU list.

How to repeat:
See i_s_innodb_fill_buffer_lru().

Suggested fix:
Add a warning note to the INNODB_BUFFER_PAGE_LRU section.
[16 Oct 2012 15:32] MySQL Verification Team 
Thank you for the bug report.
[29 Dec 2012 0:41] John Russell 
Added a warning note about both the memory allocation and locking aspects, in 5.5, 5.6, and higher Ref Mans.