Horton

Re: Some ExecSeqScan optimizations

amit <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Vladlen Popolitov <v.popolitov@postgrespro.ru>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Junwang Zhao <zhjwpku@gmail.com>
Date: 2025-01-10T11:22:41Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Refactor ExecScan() to allow inlining of its core logic

Attachments

On Fri, Jan 10, 2025 at 7:36 PM David Rowley <dgrowleyml@gmail.com> wrote:
> On Fri, 10 Jan 2025 at 22:53, Vladlen Popolitov
> <v.popolitov@postgrespro.ru> wrote:
> >   In case of query
> > select count(*) from test_table where a_1 = 1000000;
> > I would expect increase of query time due to additional if...else . It
> > is not clear
> > what code was eliminated to decrease query time.
>
> Are you talking about the code added to ExecInitSeqScan() to determine
> which node function to call? If so, that's only called during executor
> startup.  The idea here is to reduce the branching during execution by
> calling one of those special functions which has a more specialised
> version of the ExecScan code for the particular purpose it's going to
> be used for.

Looks like I hadn't mentioned this key aspect of the patch in the
commit message, so did that in the attached.

Vladlen, does what David wrote and the new commit message answer your
question(s)?

-- 
Thanks, Amit Langote