Bug #80870 Optimize TC_LOG_MMAP
Submitted: 28 Mar 2016 18:07 Modified: 27 Dec 2017 14:30
Reporter: George Lorch Email Updates:
Status: Verified Impact on me:
Category:MySQL Server: Logging Severity:S4 (Feature request)
Version:5.6, 5.7 OS:Any
Assigned to: CPU Architecture:Any

[28 Mar 2016 18:07] George Lorch
It seems TC_LOG_MMAP is not optimized nearly as well as TC_LOG_BIN.

How to repeat:
Enabling (but not necessarily using) a second transactional storage engine (such as TokuDB) and log_bin=OFF, the MySQL server will always use TC_LOG_MMAP.

We see much higher disk usage when TC_LOG_MMAP is in use (even for InnoDB only workloads) and PMP shows a lot of time spent in TC_LOG_MMAP::sync.

For more background info, see https://bugs.launchpad.net/percona-server/+bug/1550352
[27 Dec 2017 14:30] MySQL Verification Team

Thank you for your report.

I have analysed the code and concluded that this is a fully valid feature request. Hence, it is verified as one.