Re: Some ExecSeqScan optimizations

On Fri, Jan 10, 2025 at 7:36 PM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
> On Fri, 10 Jan 2025 at 22:53, Vladlen Popolitov
> <v(dot)popolitov(at)postgrespro(dot)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