From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tender Wang <tndrwang@gmail.com>
Cc: Richard Guo <guofenglinux@gmail.com>
Cc: Peter Eisentraut <peter@eisentraut.org>
Cc: exclusion@gmail.com
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19000: gist index returns inconsistent result with gist_inet_ops
Date: Fri, 01 Aug 2025 00:53:23 -0400
Message-ID: <2197759.1754024003@sss.pgh.pa.us> (raw)
In-Reply-To: <CAHewXN=qY4XqMnqbHt0r-pTvS8mZ51mabExF30XQx8C9Kg0n4Q@mail.gmail.com>
References: <19000-2525470d200672ab@postgresql.org>
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<2107725.1753985855@sss.pgh.pa.us>
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<CAHewXN=qY4XqMnqbHt0r-pTvS8mZ51mabExF30XQx8C9Kg0n4Q@mail.gmail.com>
Tender Wang <tndrwang@gmail.com> writes:
> Tom Lane <tgl@sss.pgh.pa.us> 于2025年8月1日周五 11:33写道：
>> Richard Guo <guofenglinux@gmail.com> writes:
>>> On Fri, Aug 1, 2025 at 3:17 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>>> We've known about this for, um, decades: btree_gist's support for
>>>> inet/cidr is fundamentally broken [1][2].
> What I debugged yesterday was, in gbt_inet_consistent(),
> query = convert_network_to_scalar(dquery, INETOID, &failure);
Right --- as I mentioned in one of the linked threads, the thing that
is fundamentally wrong here is relying on convert_network_to_scalar
in the first place. That has no charter to deliver exact results,
and it doesn't. In the present example I think the issue is that
it doesn't consider the netmask at all; but there are many other
cases where it's not an exact representation of inet's sort order.
That's not a big problem for its intended purpose for statistical
estimates, but it's completely fatal for index infrastructure.
regards, tom lane
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Cc: tgl@sss.pgh.pa.us, tndrwang@gmail.com, guofenglinux@gmail.com, peter@eisentraut.org, exclusion@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19000: gist index returns inconsistent result with gist_inet_ops
In-Reply-To: <2197759.1754024003@sss.pgh.pa.us>
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