On Tue, 12 Nov 2019 at 20:11, Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Tue, Nov 12, 2019 at 3:39 PM Masahiko Sawada > <masahiko.saw...@2ndquadrant.com> wrote: > > > > On Tue, 12 Nov 2019 at 18:26, Dilip Kumar <dilipbal...@gmail.com> wrote: > > > > > > On Tue, Nov 12, 2019 at 2:25 PM Amit Kapila <amit.kapil...@gmail.com> > > > wrote: > > > > > > > > Yeah, maybe something like amparallelvacuumoptions. The options can be: > > > > > > > > VACUUM_OPTION_NO_PARALLEL 0 # vacuum (neither bulkdelete nor > > > > vacuumcleanup) can't be performed in parallel > > > > VACUUM_OPTION_NO_PARALLEL_CLEANUP 1 # vacuumcleanup cannot be > > > > performed in parallel (hash index will set this flag) > > > > > > Maybe we don't want this option? because if 3 or 4 is not set then we > > > will not do the cleanup in parallel right? > > > > > Yeah, but it is better to be explicit about this.
VACUUM_OPTION_NO_PARALLEL_BULKDEL is missing? I think brin indexes will use this flag. It will end up with (VACUUM_OPTION_NO_PARALLEL_CLEANUP | VACUUM_OPTION_NO_PARALLEL_BULKDEL) is equivalent to VACUUM_OPTION_NO_PARALLEL, though. > > > > > VACUUM_OPTION_PARALLEL_BULKDEL 2 # bulkdelete can be done in > > > > parallel (Indexes nbtree, hash, gin, gist, spgist, bloom will set this > > > > flag) > > > > VACUUM_OPTION_PARALLEL_COND_CLEANUP 3 # vacuumcleanup can be done in > > > > parallel if bulkdelete is not performed (Indexes nbtree, brin, hash, > > > > gin, gist, spgist, bloom will set this flag) > > > > VACUUM_OPTION_PARALLEL_CLEANUP 4 # vacuumcleanup can be done in > > > > parallel even if bulkdelete is already performed (Indexes gin, brin, > > > > and bloom will set this flag) > > > > > > > > Does something like this make sense? > > > > 3 and 4 confused me because 4 also looks conditional. How about having > > two flags instead: one for doing parallel cleanup when not performed > > yet (VACUUM_OPTION_PARALLEL_COND_CLEANUP) and another one for doing > > always parallel cleanup (VACUUM_OPTION_PARALLEL_CLEANUP)? > > > > Hmm, this is exactly what I intend to say with 3 and 4. I am not sure > what makes you think 4 is conditional. Hmm so why gin and bloom will set 3 and 4 flags? I thought if it sets 4 it doesn't need to set 3 because 4 means always doing cleanup in parallel. > > > That way, we > > can have flags as follows and index AM chooses two flags, one from the > > first two flags for bulk deletion and another from next three flags > > for cleanup. > > > > VACUUM_OPTION_PARALLEL_NO_BULKDEL 1 << 0 > > VACUUM_OPTION_PARALLEL_BULKDEL 1 << 1 > > VACUUM_OPTION_PARALLEL_NO_CLEANUP 1 << 2 > > VACUUM_OPTION_PARALLEL_COND_CLEANUP 1 << 3 > > VACUUM_OPTION_PARALLEL_CLEANUP 1 << 4 > > > > This also looks reasonable, but if there is an index that doesn't want > to support a parallel vacuum, it needs to set multiple flags. Right. It would be better to use uint16 as two uint8. I mean that if first 8 bits are 0 it means VACUUM_OPTION_PARALLEL_NO_BULKDEL and if next 8 bits are 0 means VACUUM_OPTION_PARALLEL_NO_CLEANUP. Other flags could be followings: VACUUM_OPTION_PARALLEL_BULKDEL 0x0001 VACUUM_OPTION_PARALLEL_COND_CLEANUP 0x0100 VACUUM_OPTION_PARALLEL_CLEANUP 0x0200 -- Masahiko Sawada http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
