On 2017-03-15 15:41:22 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > On March 15, 2017 12:33:28 PM PDT, Tom Lane <t...@sss.pgh.pa.us> wrote: > >> So for my money, you should drop 0002 altogether and just have 0004 > >> remove get_last_attnums() from execUtils.c and stick it into > >> execExpr.c. I suppose you still need the LastAttnumInfo API change > >> so as to decouple it from ProjectionInfo, but that's minor. > > > I think it's quite useful in other places too, we do repeated slot-getattrs > > in a bunch of places in the executor, and it's noticeable performance wise. > > Color me dubious. Which specific other places have you got in mind, and > do they have expression trees at hand that would tell them which columns > they really need to pull out?
I was thinking of execGrouping.c's execTuplesMatch(), TupleHashTableHash() (and unequal, but doubt that matters performancewise). There's also nodeHash.c's ExecHashGetValue(), but I think that'd possibly better fixed differently. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers