MySQL Bugs: #119094: Performance optimization patches

Bug #119094	Performance optimization patches
Submitted:	29 Sep 2025 13:03	Modified:	12 Dec 2025 13:38
Reporter:	Kamil Holubicki (OCA)	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: Optimizer	Severity:	S3 (Non-critical)
Version:		OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Based on work published on https://github.com/enhancedformysql/mysql-8.0.40 by Bin Wang, Percona identified several fixes that we applied to Percona Server and hope can be incorporated in MySQL. All patches attached.

1. mem_root_deque implementation using std::list
2. Inlining hot-spot InnoDB functions
3. Revert refactoring that extracted rec_init_offset_new() function. (8.0.29, commit e8f422de).
We have found that even if a new function is declared as 'inline', the compiler doesn't decide to do so. Moreover, the introduced switch/case introduces an additional conditional jump in the generated assembly code.
4. Fix for refactoring done in commit 43e364c3 (const tables handling by optimizer).
If the optimizer detected the const table in the query, this information is not passed to test_quick_select() and may result in nonoptimal range scan boundaries.

How to repeat:
.

const tables patch

Attachment: const_tables.patch (text/x-patch), 2.75 KiB.

rec_init_offset_new patch

Attachment: rec_init_offset_new.patch (text/x-patch), 7.26 KiB.

const tables patch

(*) I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

Contribution: const_tables.patch (text/x-patch), 2.75 KiB.

rec_init_offset_new patch (*) I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

Contribution: rec_init_offset_new.patch (text/x-patch), 7.26 KiB.

inline patch (*) I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

Contribution: inline.patch (text/x-patch), 21.68 KiB.

I'm not able to add a patch for deque part. When submitting, I see the server error.
I will retry again later. 

Commits are available here:
https://github.com/percona/percona-server/commit/a45db1eb1aaa7486879cf4c360dfd5f70f445ff2
https://github.com/percona/percona-server/commit/bc0ec11d952a32afd9e2d6cdb4b6333fd9484114

Thank you for your contribution.

Thank you for your contributions. 

It would be great to if we could have some more details on the rationale for each of the patches.

Also, for future contributions, please, use different bug reports for Optimizer and InnoDB patches.  That will simplify the handling on our side.