Re: BUG #5036: Advisory locks have unexpected behavior

Dennis Seran wrote:

> - Client B again prompts the command pg_try_advisory_lock_shared(12345) in
> an attempt to reobtain the shared lock(12345) but returns false and fails to
> obtain the shared lock (SHOULDN'T THIS CLIENT BE ABLE TO OBTAIN THE SHARED
> LOCK?)

No; it gets to sleep until after client C has released the exclusive
lock.  Otherwise a constant stream of shared lockers would starvate
exclusive lockers.

> - The above result happens when all 3 clients are on the same machine.  If
> the same steps were followed, but this time with clients A and B on a RHEL
> machine and the client C and the server on an XP machine, the result is a
> bit different.  The above step results in Client B going into the queue as
> well as Client C even though Client A currently holds the shared lock.
> (AGAIN, SHOULDN'T THIS CLIENT BE ABLE TO OBTAIN THE SHARED LOCK?)

I think this sounds like a bug.

--
Alvaro Herrera                                http://www.CommandPrompt.com/
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