Re: sequence increment jumps? - Mailing list pgsql-general

From Bruce Momjian
Subject Re: sequence increment jumps?
Date
Msg-id 200701251934.l0PJYeD03931@momjian.us
Whole thread Raw
In response to Re: sequence increment jumps?  (Douglas McNaught <doug@mcnaught.org>)
List pgsql-general
Douglas McNaught wrote:
> Benjamin Smith <lists@benjamindsmith.com> writes:
>
> > On Thursday 25 January 2007 09:53, Douglas McNaught wrote:
> >> Nature of the beast. ?Sequence increments aren't rolled back on
> >> transaction abort (for performance and concurrency reasons), so you
> >> should expect gaps.
> >
> > Behavior long ago noted and accounted for. But I've always wondered why this
> > was so? Is there a specific reason for this behavior?
>
> Being able to roll back a sequence increment would require locking the
> sequence for the duration of the transaction, which would kill
> concurrency.

This is an FAQ.

--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

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