Re: Lock contention in TransactionIdIsInProgress() - Mailing list pgsql-general

From Jeff Janes
Subject Re: Lock contention in TransactionIdIsInProgress()
Date
Msg-id CAMkU=1w1BeFg6Maw_X+4arsmxcBaS0=OcCar7tgRzYDAZzd1-g@mail.gmail.com
Whole thread Raw
In response to Lock contention in TransactionIdIsInProgress()  (bock@openit.de (Julian v. Bock))
Responses Re: Lock contention in TransactionIdIsInProgress()  (bock@openit.de (Julian v. Bock))
List pgsql-general
On Thu, Nov 5, 2015 at 10:38 AM, Julian v. Bock <bock@openit.de> wrote:

> After doing some debugging it seems that the backend processes are
> spending most of their time in spinlocks in TransactionIdIsInProgress()
> trying to get a lock on ProcArrayLock. This function is called more
> often (when processing searches) the longer the replication transaction
> is running.

This is a known issue and is fixed for 9.6 in commit 8a7d0701814a4e.

I don' t know why you can't reproduce it without Slony, though.  I
know that hot standby gets bit by this problem particularly hard
because it sometimes refrains from setting hint bits as aggressively
as it could.  I would not think that Slony would have that problem,
though.

Cheers,

Jeff


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