From: Noah Misch <noah@leadboat.com>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: tgl@sss.pgh.pa.us
Cc: pryzby@telsasoft.com
Cc: pgsql-hackers@postgresql.org
Subject: Re: v13: CLUSTER segv with wal_level=minimal and parallel index creation
Date: Mon, 7 Sep 2020 02:32:55 -0700
Message-ID: <20200907093255.GA3609623@rfd.leadboat.com> (raw)
In-Reply-To: <20200907.174036.603784943439284546.horikyota.ntt@gmail.com>
References: <20200907033451.GB7158@telsasoft.com>
<1625111.1599453183@sss.pgh.pa.us>
<20200907.134528.1788420979518620237.horikyota.ntt@gmail.com>
<20200907.174036.603784943439284546.horikyota.ntt@gmail.com>
On Mon, Sep 07, 2020 at 05:40:36PM +0900, Kyotaro Horiguchi wrote:
> At Mon, 07 Sep 2020 13:45:28 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in
> > The cause is that the worker had received pending-sync entry correctly
> > but not never created a relcache entry for the relation using
> > RelationBuildDesc. So the rd_firstRelfilenodeSubid is not correctly
> > set.
> >
> > I'm investigating it.
>
> Relcaches are loaded from a file with old content at parallel worker
> startup. The relcache entry is corrected by invalidation at taking a
> lock but pending syncs are not considered.
>
> Since parallel workers don't access the files so we can just ignore
> the assertion safely, but I want to rd_firstRelfilenodeSubid flag at
> invalidation, as attached PoC patch.
> [patch: When RelationInitPhysicalAddr() handles a mapped relation, re-fill
> rd_firstRelfilenodeSubid from RelFileNodeSkippingWAL(), like
> RelationBuildDesc() would do.]
As a PoC, this looks promising. Thanks. Would you add a test case such that
the following demonstrates the bug in the absence of your PoC?
printf '%s\n%s\n%s\n' 'log_statement = all' 'wal_level = minimal' 'max_wal_senders = 0' >/tmp/minimal.conf
make check TEMP_CONFIG=/tmp/minimal.conf
Please have the test try both a nailed-and-mapped relation and a "nailed, but
not mapped" relation. I am fairly confident that your PoC fixes the former
case, but the latter may need additional code.
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To: pgsql-hackers@postgresql.org
Cc: noah@leadboat.com, horikyota.ntt@gmail.com, tgl@sss.pgh.pa.us, pryzby@telsasoft.com
Subject: Re: v13: CLUSTER segv with wal_level=minimal and parallel index creation
In-Reply-To: <20200907093255.GA3609623@rfd.leadboat.com>
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