Bug #57668 partition pruning and open files
Submitted: 22 Oct 2010 18:37 Modified: 23 Oct 2010 14:50
Reporter: Matthew Lord Email Updates:
Status: Duplicate Impact on me:
None 
Category:MySQL Server: Partitions Severity:S4 (Feature request)
Version:all OS:Any
Assigned to: CPU Architecture:Any

[22 Oct 2010 18:37] Matthew Lord 
Description:
It's easy to hit the open_files_limit when using partitioning with MyISAM, especially on Windows (prior to 5.5) where you have the hard limit of 2048.

Is it possible to do the partition pruning without having to actually open each partition?  I'm not sure if this can be done but if so it would be helpful to people with many tables that have hundreds of partitions.

How to repeat:
n/a

Suggested fix:
We should use the information stored in the frm cache or from information_schema, if possible, so that we can do partition pruning without having to open each partition on disk.
[23 Oct 2010 12:17] Davi Arnaut 
Duplicate of Bug#37252? It's essentially the same core problem.
[13 Jun 2012 15:25] Mattias Jonsson 
This is not really the same as bug#37252. That bug was solved by also prune the locks. Avoid opening (and have the partitions open when waiting in the table cache) is another worklog: wl#3513.