On Thu, 28 Nov 2019 at 11:57, Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Thu, Nov 28, 2019 at 4:10 PM Mahendra Singh <mahi6...@gmail.com> wrote: > > > > On Thu, 28 Nov 2019 at 13:32, Masahiko Sawada > > <masahiko.saw...@2ndquadrant.com> wrote: > >> > >> On Wed, 27 Nov 2019 at 19:21, Mahendra Singh <mahi6...@gmail.com> wrote: > >> > > >> > > >> > Thanks for the re-based patches. > >> > > >> > On the top of v35 patch, I can see one compilation warning. > >> >> > >> >> parallel.c: In function ‘LaunchParallelWorkers’: > >> >> parallel.c:502:2: warning: ISO C90 forbids mixed declarations and code > >> >> [-Wdeclaration-after-statement] > >> >> int i; > >> >> ^ > >> > > >> > > >> > Above warning is due to one extra semicolon added at the end of > >> > declaration line in v35-0003 patch. Please fix this in next version. > >> > + int nworkers_to_launch = Min(nworkers, pcxt->nworkers);; > >> > >> Thanks. I will fix it in the next version patch. > >> > >> > > >> > I will continue my testing on the top of v35 patch set and will post > >> > results. > > > > > > While reviewing v35 patch set and doing testing, I found that if we disable > > leader participation, then we are launching 1 less parallel worker than > > total number of indexes. (I am using max_parallel_workers = 20, > > max_parallel_maintenance_workers = 20) > > > > For example: If table have 3 indexes and we gave 6 parallel vacuum > > degree(leader participation is disabled), then I think, we should launch 3 > > parallel workers but we are launching 2 workers due to below check. > > + nworkers = lps->nindexes_parallel_bulkdel - 1; > > + > > + /* Cap by the worker we computed at the beginning of parallel lazy > > vacuum */ > > + nworkers = Min(nworkers, lps->pcxt->nworkers); > > > > Please let me know your thoughts for this.
Thanks! > I think it is probably because this part of the code doesn't consider > PARALLEL_VACUUM_DISABLE_LEADER_PARTICIPATION. I think if we want we > can change it but I am slightly nervous about the code complexity this > will bring but maybe that is fine. Right. I'll try to change so that. Regards, -- Masahiko Sawada http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
