Horton

Re: Todo: Teach planner to evaluate multiple windows in the optimal order

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Ankit Kumar Pandey <itsankitkp@gmail.com>
Cc: pghackers <pgsql-hackers@lists.postgresql.org>, Vik Fearing <vik@postgresfriends.org>
Date: 2023-01-07T22:05:15Z
Lists: pgsql-hackers 
On Sun, 8 Jan 2023 at 01:52, Ankit Kumar Pandey <itsankitkp@gmail.com> wrote:
> I am just wondering though, why can we not do top-N sort
> in optimized version if we include limit clause? Is top-N sort is
> limited to non strict sorting or
> cases last operation before limit is sort? .

Maybe the sort bound can be pushed down. You'd need to adjust
ExecSetTupleBound() so that it pushes the bound through
WindowAggState.

David

Commits

  1. Split out tiebreaker comparisons from comparetup_* functions

  2. Add additional regression tests for select_active_windows