On Thu, 18 Jul 2019 at 11:36, Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2019-07-18 11:29:37 +1200, David Rowley wrote: > > On Wed, 17 Jul 2019 at 06:46, Andres Freund <and...@anarazel.de> wrote: > > > 1) Have ExecFindPartition() return via a bool* whether the partition is > > > being accessed for the first time. In copy.c push the partition onto > > > a list of to-be-bulk-finished tables. > > > 2) Add a execPartition.c function that returns all the used tables from > > > a PartitionTupleRouting*. > > > > #2 seems better than #1 as it does not add overhead to ExecFindPartition(). > > I don't see how #1 would add meaningful overhead compared to the other > costs of that function. Wouldn't it just be adding if (isnew) *isnew = > false; to the "/* ResultRelInfo already built */" branch, and the > reverse to the else?
Yes > That got to be several orders of magnitude cheaper > than e.g. FormPartitionKeyDatum() which is unconditionally executed? Probably. However, I spent quite a bit of time trying to make that function as fast as possible in v12, and since #2 seems like a perfectly good alternative, I'd rather go with that than to add pollution to ExecFindPartition's signature. Also, #2 seems better since it keeps CopyFrom() from having to maintain a list. I think we all agreed somewhere that that code is more complex than we'd all like it to be. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
