From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> |
Cc: | "Andres Freund" <andres(at)anarazel(dot)de>, "PG Hackers" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: sequence locking |
Date: | 2011-09-21 17:24:55 |
Message-ID: | 25780.1316625895@sss.pgh.pa.us |
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"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> Andres Freund <andres(at)anarazel(dot)de> wrote:
>> - Its impossible to emulate proper locking yourself because
>> locking is not allowed for sequences
>> Any arguments against allowing it again? It seems to have been
>> allowed in prehistoric times.
If you think that it used to be allowed, it'd be a good idea to see
if you can find the archived discussions about changing it.
> It would be nice to allow it. I've had to create a dummy table just
> to use for locking a sequence (by convention).
One question is what you think the lock means. I believe for example
that taking a non-exclusive regular table lock on a sequence would not
prevent other sessions from doing nextval(); even an exclusive one would
not prevent them from doing so if they had pre-cached values.
regards, tom lane
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