On Wed, Aug 28, 2024 at 10:26 PM Richard Guo <guofenglinux@gmail.com> wrote:
> Yeah, I'm concerned about this too. In addition to the inaccuracies
> in aggregation estimates, our estimates for joins are sometimes not
> very accurate either. All this are likely to result in regressions
> with eager aggregation in some cases. Currently I don't have a good
> answer to this problem. Maybe we can run some benchmarks first and
> investigate the regressions discovered on a case-by-case basis to better
> understand the specific issues.
While it's true that we can make mistakes during join estimation, I
believe aggregate estimation tends to be far worse.
--
Robert Haas
EDB: http://www.enterprisedb.com