On 23 April 2016 at 06:35, Robert Haas <robertmh...@gmail.com> wrote: > 2. You're using the term "combine agg", but as far as the EXPLAIN > ANALYZE output is concerned, that's not a thing. There is > PartialAggregate, Aggregate, and FinalizeAggregate. I think you mean > FinalizeAggregate when you say "combine aggregate", since we identify > a node as a FinalizeAggregate by observing that combineStates = true.
I really do mean combine when I say combine. I'm pretty sure that I've coded everything properly to work even if there was 10 stages of aggregation, in this case 9 of those would be combine nodes, and only 1 of them a finalize node. I can see why you'd say that at a glace of explain.c, but it's more relevant that agg->finalizeAggs is true, giving the combine test is in the else if condition. The test for combineStates is only there so we don't output Finalize Aggregate for normal 1 stage aggregates. I simply don't think FILTER should be shown if combineStates is true. This means that it will only be shown at the first aggregate node, the one with combineStates == false. I think this is a good idea due to the fact that this is the only place where FILTERing is done. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers