Re: using database for queuing operations? - Mailing list pgsql-general

From Jim C. Nasby
Subject Re: using database for queuing operations?
Date
Msg-id 20040922181954.GU1297@decibel.org
Whole thread Raw
In response to Re: using database for queuing operations?  (John Sidney-Woollett <johnsw@wardbrook.com>)
Responses Re: using database for queuing operations?  (John Sidney-Woollett <johnsw@wardbrook.com>)
List pgsql-general
Ahh, yes, forgot about that. Very handy to have. But even without that
you wouldn't have a race condition, just a blocked process, right?

On Tue, Sep 21, 2004 at 07:15:08AM +0100, John Sidney-Woollett wrote:
> Oracle also has the NOWAIT option for use with the SELECT ... FOR UPDATE
> query. If the record is locked, the NOWAIT causes the query to generate
> an exception (rather than blocking) which can then be caught and handled
> - it helps prevent race conditions. A very nice feature!
>
> John Sidney-Woollett
>
> Jim C. Nasby wrote:
> >What's the race in the SELECT FOR UPDATE?
> >
> >BTW, this is one nice thing about Oracle... it comes with a built-in
> >queuing mechanism. It would probably be worth trying to write a generic
> >queuing system and stick it in Gborg.
> >
> >Incidentally, Oracle also supports user-named locks, which would
> >probably make this easier to do. LOCK TABLE works, but it's more brute
> >force than is needed. Unfortunately, I don't see a way to simply add
> >such a thing onto PostgreSQL without adding it to the core.
>
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Jim C. Nasby, Database Consultant               decibel@decibel.org
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