Bug #85910 | Increased Performance_Schema overhead on Sending data | ||
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Submitted: | 12 Apr 2017 3:00 | Modified: | 24 Oct 2023 14:22 |
Reporter: | Jervin R | Email Updates: | |
Status: | Can't repeat | Impact on me: | |
Category: | MySQL Server: Performance Schema | Severity: | S3 (Non-critical) |
Version: | 5.6.35, 5.6.36 | OS: | Any |
Assigned to: | Marc ALFF | CPU Architecture: | Any |
[12 Apr 2017 3:00]
Jervin R
[12 Apr 2017 4:03]
Jervin R
vagrant@trusty:~$ mysql -e 'select version(), @@version_comment' +-----------+------------------------------+ | version() | @@version_comment | +-----------+------------------------------+ | 5.6.36 | MySQL Community Server (GPL) | +-----------+------------------------------+ PS ON vagrant@trusty:~$ time mysql test -e 'select a from ps where id between 1 and 2000000' > /dev/null real 0m4.718s user 0m0.270s sys 0m0.029s PS OFF vagrant@trusty:~$ time mysql test -e 'select a from ps where id between 1 and 2000000' > /dev/null real 0m0.948s user 0m0.350s sys 0m0.021s vagrant@trusty:~$ cat /etc/issue.net Ubuntu 14.04.5 LTS vagrant@trusty:~$ uname -a Linux trusty 3.13.0-113-generic #160-Ubuntu SMP Thu Mar 9 09:27:29 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
[12 Apr 2017 5:35]
Jervin R
Seems to be platform dependent, I tested on Xenial and performance is the same with PS on or off. revin@acme:/data/msb/msb_5_6_36$ time ./use test -e 'select a from ps where id between 1 and 2000000' > /dev/null real 0m0.887s user 0m0.404s sys 0m0.036s revin@acme:/data/msb/msb_5_6_36$ uname -a Linux acme 4.4.0-64-generic #85-Ubuntu SMP Mon Feb 20 11:50:30 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux revin@acme:/data/msb/msb_5_6_36$ cat /etc/issue.net Ubuntu 16.04.2 LTS revin@acme:/data/msb/msb_5_6_36$
[12 Apr 2017 15:15]
MySQL Verification Team
this is a known issue on 5.6. If you look deeper, I suppose poor mans profiler will show up with many my_timer_cycles or rdtsc in the stacks? 5.7+ is better for this case.
[13 Apr 2017 8:50]
MySQL Verification Team
Hello Jervin R, Thank you for the report. Observed a very minor performance impact when p_s enabled and disabled. Also, this overhead seems to be fixed in 5.7, after http://dev.mysql.com/worklog/task/?id=7802 Thanks, Umesh
[13 Apr 2017 8:51]
MySQL Verification Team
test results
Attachment: 85910_5.6.36 (application/octet-stream, text), 3.84 KiB.
[14 Apr 2017 6:02]
Jervin R
Umesh, thanks for the verification. Shane, interesting - Indeed, that's what I am seeing from perf. Any particular reason why the tests on Ubuntu 14.04 varies widely against 16.04?
[24 Oct 2023 14:22]
Marc ALFF
In MySQL 5.6, the table io instrumentation caused overhead when returning a lot of rows in a result set. This has been fixed in MySQL 5.7 by: WL#7802: PERFORMANCE SCHEMA, BATCH TABLE IO No longer reproducible in 5.7 and up.