Re: sequence locking - Mailing list pgsql-hackers

From Tom Lane
Subject Re: sequence locking
Date
Msg-id 25780.1316625895@sss.pgh.pa.us
Whole thread Raw
In response to Re: sequence locking  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
Responses Re: sequence locking
List pgsql-hackers
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Andres Freund <andres@anarazel.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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