public inbox for [email protected]  

help / color / mirror / Atom feed
From: Andrey M. Borodin <[email protected]>
To: Michael Paquier <[email protected]>
Cc: Bernd Helmle <[email protected]>
Cc: jian he <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: [PATCH] Add sortsupport for range types and btree_gist
Date: Fri, 29 Nov 2024 14:41:56 +0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>

Thanks for your valuable input, Michael!

> On 29 Nov 2024, at 09:42, Michael Paquier <[email protected]> wrote:
> 
> As a whole, I'm very dubious about the need for injection points at
> all here.  The sortsupport property claimed for this patch tells that
> this results in smaller index sizes, but the tests don't really check
> that: they just make sure that sortsupport routine paths are taken.
> What this should test is not the path taken, but how the new code
> affects the index data generated.

Actually, that’s exactly what we wanted to test: which paths are taken.
Resulting index might be of a very same size in case of B-tree-over-GiST. Resulting index is drastically smaller for geometry, e.g. PostGIS. But event that’s not main effect: the index is simply build much faster (on par with actual B-tree).
We need this sort support for btree_gist to be able to use non-geometry datatypes in combination with geometry.
e.g.
CREATE INDEX ON table USING gist(project_id_of_type_int,geometric_column);
Currently, having anything non-geometric in GiST slows down it 10x, because sorting build path is not taken.
In PG15 we put extra effort to make resulting indexes indistinguishable from normally-built. Primarily for the sake of IndexScan performance.


Best regards, Andrey Borodin.








view thread (23+ messages)  latest in thread

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: [PATCH] Add sortsupport for range types and btree_gist
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox