Re: Processing a work queue

Merlin Moncure wrote:
> ok, here's an example. I was thinking that my sequence idea might not
> be safe because of race conditions revolving around querying the
> sequence table. Here is how I might use advisory locks eliminate the

I've seen your name pop up regularly on this list (or are you from
freebsd-stable?), so you kind of got me scratching my head whether you
really don't understand sequences. Kind of hard to imagine... Maybe I
don't understand what you're asking.

Sequences are safe in concurrent use.
* Nextval() always returns a new number, so no two concurrent sessions
can get the same one.
* Currval() is only valid within one session after calling nextval(), so
it's number cannot have been modified by another session.

Why do you expect to need locking?

--
Alban Hertroys
alban(at)magproductions(dot)nl

magproductions b.v.

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