From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: John Naylor <john.naylor@enterprisedb.com>
Cc: tharakan@gmail.com
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17774: Assert triggered on brin_minmax_multi.c
Date: Wed, 08 Feb 2023 11:05:16 -0500
Message-ID: <3492169.1675872316@sss.pgh.pa.us> (raw)
In-Reply-To: <20230208153313.fym7at3ubgrec67a@ddolgov.remote.csb>
References: <17774-c6f3e36dd4471e67@postgresql.org>
<CAFBsxsEMigeTVhBOpsBHw+SJS1n776akNqVC8ATEDmGo_OPgrw@mail.gmail.com>
<20230208100658.mz2kkeruoma6iqtw@ddolgov.remote.csb>
<3485884.1675868581@sss.pgh.pa.us>
<20230208153313.fym7at3ubgrec67a@ddolgov.remote.csb>
Dmitry Dolgov <9erthalion6@gmail.com> writes:
>> On Wed, Feb 08, 2023 at 10:03:01AM -0500, Tom Lane wrote:
>> I'd believe this argument more readily if the calculation weren't being
>> done in float arithmetic. Since it is, you're at the mercy of roundoff
>> error ... and that small negative delta could certainly pass for
>> roundoff error.
> Hmm...yeah, good point. In both the reproducer I've posted and the
> backtrace from the thread the delta is indeed rather small.
I bet also it only fails when dealing with IPv6 addresses.
With 32-bit IPv4 addresses, a float8 would have enough mantissa
bits that the calculation wouldn't become imprecise.
regards, tom lane
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: pgsql-bugs@postgresql.org
Cc: tgl@sss.pgh.pa.us, 9erthalion6@gmail.com, john.naylor@enterprisedb.com, tharakan@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17774: Assert triggered on brin_minmax_multi.c
In-Reply-To: <3492169.1675872316@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox