From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andreas Karlsson <andreas@proxel.se>
cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
        pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: btree_gist into core?
In-reply-to: <a4a4c618-37a1-f004-6916-e70b788499c9@proxel.se>
References: <5fd19680-c0db-e9ea-eae6-971a369b4233@enterprisedb.com> <a4a4c618-37a1-f004-6916-e70b788499c9@proxel.se>
Comments: In-reply-to Andreas Karlsson <andreas@proxel.se>
	message dated "Tue, 25 Jan 2022 00:10:30 +0100"
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Date: Mon, 24 Jan 2022 18:29:24 -0500
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Andreas Karlsson <andreas@proxel.se> writes:
> On 1/19/22 09:30, Peter Eisentraut wrote:
>> I don't have a lot of experience with this module, so I don't know if 
>> there are any lingering concerns about whether it is mature enough as a 
>> built-in feature.

> While it I like the idea on a conceptual level I worry about the code 
> quality of the module. I know that the btree/cidr code is pretty broken. 
> But I am not sure if there are any issues with other data types.

Yeah :-(.  We just fixed an issue with its char(n) support too
(54b1cb7eb), so I don't have a terribly warm feeling about the
quality of the lesser-used code paths.  Still, maybe we could
do some code review/testing rather than a blind copy & paste.

I'd also opine that we don't have to preserve on-disk compatibility
while migrating into core, which'd help get out of the sticky problem
for inet/cidr.  This'd require being able to run the contrib module
alongside the core version for awhile (to support existing indexes),
but I think we could manage that if we tried.  IIRC we did something
similar when we migrated tsearch into core.

One thing I don't know anything about is how good are btree_gist
indexes performance-wise.  Do they have problems that we'd really
need to fix to consider them core-quality?

			regards, tom lane