MySQL Bugs: #26453: patch to speed up range-optimizer

Bug #26453	patch to speed up range-optimizer
Submitted:	16 Feb 2007 17:05	Modified:	18 Dec 2008 13:13
Reporter:	Martin Friebe (Gold Quality Contributor) (OCA)	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: MyISAM storage engine	Severity:	S5 (Performance)
Version:	5.0.36bk	OS:	Any (*)
Assigned to:		CPU Architecture:	Any
Tags:	Contribution, qc, range optimizer

Description:
In mi_range.c and mi_search.c, while executing _mi_record_pos for packed keys, the code walks each index node twice.

1st calling *bin_search, to match the key in the node
2nd calling _mi_keynr, to find the position and the total amount.

The position can easily be returned from *bin_search.
In order to find the total amount of keys in the node, it is only needed to continue from the position returned by *bin_search

Doing this saves between 10% and 20% time (of the statistics time) when estimating the range for "key IN(huge list)".

Applying it together with the patch from bug #20944 an overall of up to 30% on those range statistics can be saved.

How to repeat:
-

Suggested fix:
apply the patch

patch to reduce amount of node scans during range statistic on packed keys

Attachment: range2.patch (text/x-patch), 14.52 KiB.

Thank you for the bug report and the contribution.

- No CSC is bound to this bug.
- This is not an optimizer optimization. This is an optimization for the MyISAM engine.

I move the bug to 'To be fixed later'.
Product management will decide in what version this optimization appears.

why is it assigned to me, or rather the question is,
how is it related to InnoDB?