Re: Eager aggregation, take 3

On Tue, Aug 27, 2024 at 11:57 PM Tender Wang <tndrwang(at)gmail(dot)com> wrote:
> Rectenly, I do some benchmark tests, mainly on tpch and tpcds.
> tpch tests have no plan diff, so I do not continue to test on tpch.

Interesting to know.

> tpcds(10GB) tests have 22 plan diff as below:
> 4.sql, 5.sql, 8.sql,11.sql,19.sql,23.sql,31.sql, 33.sql,39.sql,45.sql,46.sql,47.sql,53.sql,
> 56.sql,57.sql,60.sql,63.sql,68.sql,74.sql,77.sql,80.sql,89.sql

OK.

> 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.

> I will continue to do benchmark on this feature.
>
> [1] https://github.com/tenderwg/eager_agg

Thanks!

--
Robert Haas
EDB: http://www.enterprisedb.com