Re: NT + deadlock intended behaviour ?

On Sun, Jul 18, 2004 at 01:38:57AM -0400, Tom Lane wrote:
> Gaetano Mendola <mendola(at)bigfoot(dot)com> writes:
> > why SESSION 1 was unblocked ?
> > ...
> > Why that commit unblock the SESSION 1?
>
> IMHO session 1 should have been unblocked in both cases as soon as
> session 2's subtransaction failed. We have always made a practice
> of releasing a transaction's locks immediately upon failure.
>
> The reason it does not seem to act that way is that Alvaro's taken a
> shortcut in WaitForTransaction: subtransactions do not take out a
> separate transaction lock and so WaitForTransaction has to wait for the
> top-level transaction. Your sub-COMMIT fails the outer transaction
> (because the inner one is failed) and so the top transaction lock
> releases at that point. In the sub-ABORT case the outer transaction
> stays good and continues to hold its lock.
>
> I've already suggested that this shortcut is no good, and now I'm
> pretty sure of it ...

FYI, this is no longer the case with the savepoints patch I just posted.
It's too late here to check if this solves Gaetano concerns.

Gaetano, please apply the latest savepoints patch (savepoint-5.patch)
and let me know how it goes ...

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"Ni aun el genio muy grande llegaría muy lejos
si tuviera que sacarlo todo de su propio interior" (Goethe)