Greetings, * Andres Freund (and...@anarazel.de) wrote: > On 2018-11-26 19:13:17 -0500, Stephen Frost wrote: > > * Andres Freund (and...@anarazel.de) wrote: > > > On 2018-11-26 19:05:02 -0500, Stephen Frost wrote: > > > > Agreed, but I could see us having a regression test which complains if > > > > it finds any which are marked as immutable but aren't parallel safe. > > > > > > That doesn't help if a user writes a query to review the not parallel > > > safe functions in their installation. > > > > I'm really not sure what you're getting at here..? > > You replied to me saying it'd be a bad idea to infer parallel safety > from immutability:
I don't think we should programatically assume it, but given that it's very likely the case, we should have a check (as you suggested in the other thread) that makes PG developers at least think about it. > > > > Surely a simple rule could be made that provolatile='i' trumps > > > > proparallel. No need to make them agree. > > > > [...] > > > > > > I think it'd be entirely unacceptable that > > > SELECT * FROM pg_proc WHERE proparallel = 's' > > > wouldn't actually return all the functions that are parallel safe. > > > > Agreed, but I could see us having a regression test which complains if > > it finds any which are marked as immutable but aren't parallel safe. > > I'm saying that that doesn't address my concern. Then I'm unclear as to what the concern here is..? > > Parallel safe functions should be marked as such. Immutable functions > > should be marked as such. We should not assume that one implies the > > other, nor should we operate as if they do. > > > > My suggestion for a regression test was to make PG developers really > > think about if their new immutable functions should also be marked as > > parallel safe, in the event that they forget to mark it as such. If > > it's really immutable and not parallel safe, then they need to adjust > > the expected regression test output (and we can all see it...). > > See > http://archives.postgresql.org/message-id/20181126234521.rh3grz7aavx2ubjv%40alap3.anarazel.de Right, so you're also suggestion we have a regression test for it.. I'm starting to wonder if maybe we're in violent agreement here..? Thanks! Stephen
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