On Thu, 16 Jan 2020 at 14:11, Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Thu, Jan 16, 2020 at 10:11 AM Mahendra Singh Thalor > <mahi6...@gmail.com> wrote: > > > > On Thu, 16 Jan 2020 at 08:22, Amit Kapila <amit.kapil...@gmail.com> wrote: > > > > > > > 2. > > > > I checked time taken by vacuum.sql test. Execution time is almost same > > > > with and without v45 patch. > > > > > > > > Without v45 patch: > > > > Run1) vacuum ... ok 701 ms > > > > Run2) vacuum ... ok 549 ms > > > > Run3) vacuum ... ok 559 ms > > > > Run4) vacuum ... ok 480 ms > > > > > > > > With v45 patch: > > > > Run1) vacuum ... ok 842 ms > > > > Run2) vacuum ... ok 808 ms > > > > Run3) vacuum ... ok 774 ms > > > > Run4) vacuum ... ok 792 ms > > > > > > > > > > I see some variance in results, have you run with autovacuum as off. > > > I was expecting that this might speed up some cases where parallel > > > vacuum is used by default. > > > > I think, this is expected difference in timing because we are adding > > some vacuum related test. I am not starting server manually(means I am > > starting server with only default setting). > > > > Can you once test by setting autovacuum = off? The autovacuum leads > to variability in test timing. > >
I've also run the regression tests with and without the patch: * w/o patch and autovacuum = on: 255 ms * w/o patch and autovacuum = off: 258 ms * w/ patch and autovacuum = on: 370 ms * w/ patch and autovacuum = off: 375 ms > > If we start server with default settings, then we will not hit vacuum > > related test cases to parallel because size of index relation is very > > small so we will not do parallel vacuum. Right. Most indexes (all?) of tables that are used in the regression tests are smaller than min_parallel_index_scan_size. And we set min_parallel_index_scan_size to 0 in vacuum.sql but VACUUM would not be speeded-up much because of the relation size. Since we instead populate new table for parallel vacuum testing the regression test for vacuum would take a longer time. Regards, -- Masahiko Sawada http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
