Bug #88739 Mysql scalability improvement patch: Optimized away excessive condition
Submitted: 4 Dec 2017 6:31 Modified: 29 Mar 2018 14:56
Reporter: Sandeep Sethia (OCA) Email Updates:
Status: Closed Impact on me:
Category:MySQL Server: InnoDB storage engine Severity:S5 (Performance)
Version:5.7.19 OS:Ubuntu (16.0.2)
Assigned to: CPU Architecture:ARM
Tags: Contribution, innodb

[4 Dec 2017 6:31] Sandeep Sethia
trx_set_rw_mode() is never called for read-only transactions, this is guarded by callers. Removing the read calls  from critical section(write only trx) immediately gives  scalability improvement in OLTP index updates benchmark. Please review the patch .

This has already been applied in Mariadb.

How to repeat:
This is a code contribution
[4 Dec 2017 6:32] Sandeep Sethia
Optimized away excessive condition 

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

Contribution: optimizedtrx.patch (application/octet-stream, text), 769 bytes.

[4 Dec 2017 7:19] Umesh Shastry
Hello Sandeep Sethia,

Thank you for the report and contribution.

[29 Mar 2018 14:56] Daniel Price
Posted by developer:
Fixed as of the upcoming 5.7.23, 8.0.12 release, and here's the changelog entry:

An unnecessary check for read-only transactions was removed from the
trx_set_rw_mode() function. Thanks to Sandeep Sethia for the patch.