Richard Guo <guofengli...@gmail.com> 于2024年8月29日周四 10:46写道：
> On Wed, Aug 28, 2024 at 9:01 PM Robert Haas <robertmh...@gmail.com> wrote: > > On Tue, Aug 27, 2024 at 11:57 PM Tender Wang <tndrw...@gmail.com> wrote: > > > I haven't look all of them. I just pick few simple plan test(e.g. > 19.sql, 45.sql). > > > For example, 19.sql, eager agg pushdown doesn't get large gain, but a > little > > > performance regress. > > > > Yeah, this is one of the things I was worried about in my previous > > reply to Richard. It would be worth Richard, or someone, probing into > > exactly why that's happening. My fear is that we just don't have good > > enough estimates to make good decisions, but there might well be > > another explanation. > > It's great that we have a query to probe into. Your guess is likely > correct: it may be caused by poor estimates. > > Tender, would you please help provide the outputs of > > EXPLAIN (COSTS ON, ANALYZE) > > on 19.sql with and without eager aggregation? > > I upload EXPLAIN(COSTS ON, ANALYZE) test to [1]. I ran the same query three times, and I chose the third time result. You can check 19_off_explain.out and 19_on_explain.out. [1] https://github.com/tenderwg/eager_agg -- Tender Wang
