Re: BUG #9485: RFE - cycling sequence rollover to do modulo - Mailing list pgsql-bugs

From Alvaro Herrera
Subject Re: BUG #9485: RFE - cycling sequence rollover to do modulo
Date
Msg-id 20140309234715.GH4759@eldon.alvh.no-ip.org
Whole thread Raw
In response to BUG #9485: RFE - cycling sequence rollover to do modulo  (Paul.Murray@environment.gov.au)
List pgsql-bugs
Paul.Murray@environment.gov.au wrote:

> When a sequence with a cycle does a rollover, it sets itself to its minimum
> value.
>
> I would like an option to create a sequence that resets to the minimum value
> plus the amount by which the next number exceeded the maximum. Perhaps like
> this:
>
> create sequence foo increment 616 min value 0 maxvalue 999 cycle modulo;

Would this be useful?

http://www.postgresql.org/message-id/CA+U5nMKh+pmbaGUd_x9ev-F5k+whT8HM7wXfkX9ouF=cPkAQEg@mail.gmail.com

You'd have to create a new "sequence access method" that provided the
behavior you want.

I think it'd be interesting to have an implementation of the behavior
you want on top of the proposed patch.

--
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

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