Re: -1/0 virtualtransaction - Mailing list pgsql-general

From Mike Beachy
Subject Re: -1/0 virtualtransaction
Date
Msg-id CAEoC5=H6xCMytEPzXKiU2NGuD332TeWVmNhvCy9BGs4QpqgQJw@mail.gmail.com
Whole thread Raw
In response to Re: -1/0 virtualtransaction  (Thomas Munro <thomas.munro@gmail.com>)
Responses Re: -1/0 virtualtransaction  (Mike Beachy <mbeachy@gmail.com>)
List pgsql-general
On Fri, Apr 30, 2021 at 7:12 AM Thomas Munro <thomas.munro@gmail.com> wrote:
> But do you have lots of short overlapping transactions so that there
> is never a moment where there are zero transactions running?

Yeah, that almost certainly explains it.

Thanks very much for the explanation about the summarized locks.

> The number of SERIALIZABLEXACT objects is (max_connections +
> max_prepared_transactions) * 10.  So, you could try increasing
> max_connections (without increasing the actual number of connections)
> to see if you can get to a point where you don't see these invalid
> virtual xids, and then maybe it'll be able to clean up locks more
> aggressively.

Aha! I hadn't considered that some parameter besides
max_pred_locks_per_transaction would come into play.  I'll give this a
shot.

Thanks,
Mike



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