From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Relations being opened without any lock whatever
Date: Mon, 01 Oct 2018 09:29:18 -0400
Message-ID: <21004.1538400558@sss.pgh.pa.us> (raw)
In-Reply-To: <eda81aff-89c2-aed4-2997-548d1b4615e5@lab.ntt.co.jp>
References: <2038.1538335244@sss.pgh.pa.us>
<eda81aff-89c2-aed4-2997-548d1b4615e5@lab.ntt.co.jp>
Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> writes:
> On 2018/10/01 4:20, Tom Lane wrote:
>> Running the regression tests with the patch I showed in
>> https://www.postgresql.org/message-id/16565.1538327894@sss.pgh.pa.us> Maybe you've noticed but the relation_open calls coming from bootstrap.c
> all pass NoLock which trigger the WARNING:
Yeah, I'd missed noticing that at the time I posted that patch, but I
sure noticed after changing the WARNING to an Assert ;-)
> Do we need to do something about that, like teaching boot_openrel() and
> gettype() in bootstrap.c to pass AccessShareLock instead of NoLock?
No, bootstrap mode has no need for locking. I think the right fix is
just to skip the check:
+ /*
+ * If we didn't get the lock ourselves, assert that caller holds one,
+ * except in bootstrap mode where no locks are used.
+ */
+ Assert(lockmode != NoLock ||
+ IsBootstrapProcessingMode() ||
+ CheckRelationLockedByMe(r, AccessShareLock, true));
It's possible that at some point we'd decide to make bootstrap mode
do locking the same as normal mode, but that's not a change I want
to make as part of this patch.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, Langote_Amit_f8@lab.ntt.co.jp, pgsql-hackers@lists.postgresql.org
Subject: Re: Relations being opened without any lock whatever
In-Reply-To: <21004.1538400558@sss.pgh.pa.us>
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