On Thu, Sep 15, 2022 1:15 PM Wang, Wei/王 威 <wangw(dot)fnst(at)fujitsu(dot)com> wrote:
>
> Attach the new patch set.
>
Hi,
I did some performance tests for "rollback to savepoint" cases, based on v28
patch.
This test used synchronous logical replication, and compared SQL execution times
before and after applying the patch. It tested different percentage of changes
in the transaction are rolled back (use "rollback to savepoint"), when using
different logical_decoding_work_mem.
The test was performed ten times, and the average of the middle eight was taken.
The results are as follows. The bar charts and the scripts of the test are
attached. The steps to reproduce performance test are at the beginning of
`start_pub.sh`.
RESULT - rollback 10% (5kk)
---------------------------------------------------------------
logical_decoding_work_mem 64kB 256kB 64MB
HEAD 43.752 43.463 42.667
patched 32.646 30.941 31.491
Compare with HEAD -25.39% -28.81% -26.19%
RESULT - rollback 20% (5kk)
---------------------------------------------------------------
logical_decoding_work_mem 64kB 256kB 64MB
HEAD 40.974 40.214 39.930
patched 28.114 28.055 27.550
Compare with HEAD -31.39% -30.23% -31.00%
RESULT - rollback 30% (5kk)
---------------------------------------------------------------
logical_decoding_work_mem 64kB 256kB 64MB
HEAD 37.648 37.785 36.969
patched 29.554 29.389 27.398
Compare with HEAD -21.50% -22.22% -25.89%
RESULT - rollback 50% (5kk)
---------------------------------------------------------------
logical_decoding_work_mem 64kB 256kB 64MB
HEAD 32.312 32.201 32.533
patched 30.238 30.244 27.903
Compare with HEAD -6.42% -6.08% -14.23%
(If "Compare with HEAD" is a positive number, it means worse than HEAD; if it is
a negative number, it means better than HEAD.)
Summary:
In general, when using "rollback to savepoint", the more the amount of data we
need to rollback, the smaller the improvement compared to HEAD. But as such
cases won't be often, this should be okay.
Regards,
Shi yu
