MySQL Bugs: #55651: number of flushed pages in innodb should not exceed what the caller has requeste

Bug #55651	number of flushed pages in innodb should not exceed what the caller has requeste
Submitted:	30 Jul 2010 14:56	Modified:	13 Jan 2011 18:56
Reporter:	Inaam Rana	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: InnoDB storage engine	Severity:	S3 (Non-critical)
Version:	5.5	OS:	Any
Assigned to:	Inaam Rana	CPU Architecture:	Any

Description:
When flushing buffer pool pages (whether LRU or flush_list flush) if the number of pages to be flushed is provided by the caller then we should honor that number. Previously when we attempted to flush the neighbors of a page we did not took into account this limit. What this meant was that we can flush up to 63 extra pages then what was requested. With introduction of multiple buffer pool we can possibly end up flushing 63 * buffer_pool_instances more pages in one batch.

This patch restricts us to flush only as many pages as are requested by the caller (with a possible off by one overstepping).

How to repeat:
see above

Suggested fix:
Restrict the number of pages that flushed.