On Sat, Mar 28, 2020 at 02:38:27PM +0100, Julien Rouhaud wrote: > On Sat, Mar 28, 2020 at 04:14:04PM +0530, Amit Kapila wrote: > > > > I see some basic problems with the patch. The way it tries to compute > > WAL usage for parallel stuff doesn't seem right to me. Can you share > > or point me to any test done where we have computed WAL for parallel > > operations like Parallel Vacuum or Parallel Create Index? > > Ah, that's indeed a good point and AFAICT WAL records from parallel utility > workers won't be accounted for. That being said, I think that an argument > could be made that proper infrastructure should have been added in the > original > parallel utility patches, as pg_stat_statement is already broken wrt. buffer > usage in parallel utility, unless I'm missing something.
Just to be sure I did a quick test with pg_stat_statements behavior using parallel/non-parallel CREATE INDEX and VACUUM, and unsurprisingly buffer usage doesn't reflect parallel workers' activity. I added an open for that, and adding Robert in Cc as 9da0cc352 is the first commit adding parallel maintenance.
