On Tue, Apr 27, 2021 at 8:07 AM Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2021-04-26 23:59:17 +0200, Tomas Vondra wrote: > > On 4/26/21 9:27 PM, Andres Freund wrote: > > > On 2021-04-26 15:31:02 +0200, Tomas Vondra wrote: > > > > I'm not sure what to do about this :-( I don't have any ideas about how > > > > to > > > > eliminate this overhead, so the only option I see is reverting the > > > > changes > > > > in heap_insert. Unfortunately, that'd mean inserts into TOAST tables > > > > won't > > > > be frozen ... > > > > > > ISTM that the fundamental issue here is not that we acquire pins that we > > > shouldn't, but that we do so at a much higher frequency than needed. > > > > > > It's probably too invasive for 14, but I think it might be worth exploring > > > passing down a BulkInsertState in nodeModifyTable.c's > > > table_tuple_insert() iff > > > the input will be more than one row. > > > > > > And then add the vm buffer of the target page to BulkInsertState, so that > > > hio.c can avoid re-pinning the buffer. > > > > > > > Yeah. The question still is what to do about 14, though. Shall we leave the > > code as it is now, or should we change it somehow? It seem a bit unfortunate > > that a COPY FREEZE optimization should negatively influence other (more) > > common use cases, so I guess we can't just keep the current code ... > > I'd suggest prototyping the use of BulkInsertState in nodeModifyTable.c > and see whether that fixes the regression.
Is this idea to have RelationGetBufferForTuple() skip re-pinning vmbuffer? If so, is this essentially the same as the one in the v3 patch? Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
