On Wed, Aug 12, 2026 at 11:01 AM Haibo Yan <[email protected]> wrote: > I’d like to propose a small optimization for aggregate-local ORDER BY in > COUNT. > Currently, for example: > > SELECT count(a ORDER BY b) FROM t; > > is planned as an ordered aggregate, even though the ordering cannot affect the > result of COUNT. This may require a Sort, but the impact is broader than just > the extra sort: having aggorder also prevents partial aggregation and hash > aggregation, and prevents the aggregate from sharing state with an otherwise > identical count(a).
The question that comes to mind is, why would someone (or a program for that matter) write it this way? Self-join elimination cited ORMs as a motivation, what is it for this case? -- John Naylor Amazon Web Services
