Re: Reaping Temp tables to avoid XID wraparound

On Mon, 18 Feb 2019 at 12:31, Michael Paquier <michael(at)paquier(dot)xyz> wrote:

> On Sun, Feb 17, 2019 at 05:47:09PM +0100, Magnus Hagander wrote:
> > We could I guess add a field specifically for temp_namespace_xid or such.
> > The question is if it's worth the overhead to do that.
>
> That would mean an extra 4 bytes in PGPROC, which is something we
> could live with, still the use-case looks rather narrow to me to
> justify that.
>

I agree the use case is narrow - but it's also pretty critical.

This is a very real way that transaction wraparound can be hit, with no
automated or manual way of solving it (apart from randomly terminating
backends (you have to search via user and hope there is only one, and that
it matches the temp table owner) or restarting Postgres).

I suppose an in-core way of disconnecting idle sessions after x time would
work too - but that seems like a sledgehammer approach.

--
James

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