Re: <IDLE> and waiting

On Feb 1, 2008 3:56 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> "Gurjeet Singh" <singh(dot)gurjeet(at)gmail(dot)com> writes:
> > The situation seems pretty bad!!
>
> I think at least part of your problem is not understanding that a single
> transaction sees a frozen snapshot of pg_stat_activity.
>
>
It does! I assumed that pg_stat_activity produced the
transaction-independent snapshot of internal memory structures! Is that the
case with pg_locks too!? I hope not.

BTW, we cannot say that the pg_stat_activity behaves in a consistent manner
(transactions-wise). From what I could infer, this view's results are frozen
when you first query the view, not when the transaction started (which is
how other (normal) relations behave). It's a bit confusing, and should be
documented if this is the way it is intended to work; Something along the
lines of : "In a transaction, this view will repeatedly show the same
results that were returned by it's first invocation in the transaction." in
a less confusing way :)

So we are back to the original problem... Canceling a 'waiting' transaction
does not revert the session's 'waiting' state back to 'false' (consistently
reproducible).

--
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