SV: Problem with pg_notify / listen - Mailing list pgsql-general

From Gustavsson Mikael
Subject SV: Problem with pg_notify / listen
Date
Msg-id 19d46e8276a54d24b09b6bcbd3bc8e17@smhi.se
Whole thread Raw
In response to Re: Problem with pg_notify / listen  ("David G. Johnston" <david.g.johnston@gmail.com>)
List pgsql-general

Hi David,


Thanks for fast reply!


We had to restart the server to avoid problems with a full queue så process is no longer with us. 


The queue is at 25% now and we have minimised the payload to avoid problems during the weekend.
# select * from pg_notification_queue_usage()
;
 pg_notification_queue_usage 
-----------------------------
           0.245367050170898
(1 row)

If my calculations is correct we will reach 50% on monday.

kr
/Mikael Gustavsson


Från: David G. Johnston <david.g.johnston@gmail.com>
Skickat: den 27 november 2020 15:28
Till: Gustavsson Mikael
Kopia: pgsql-generallists.postgresql.org; Svensson Peter; Almen Anders
Ämne: Re: Problem with pg_notify / listen
 
On Friday, November 27, 2020, Gustavsson Mikael <mikael.gustavsson@smhi.se> wrote:

Hi.

After applying the latest patch we have encountered a problem with the pg_notify queue. 

The queue is filling up and starts issuing warnings like 
WARNING:  NOTIFY queue is 87% full
DETAIL:  The server process with PID 2969993 is among those with the oldest transactions.
NOTIFY queue cannot be emptied until that process ends its current transaction.

There is no long-running 'active' or 'idle in transaction' transactions on the server.
 

As its easy enough to run can you please confirm this by showing us the pg_stat_activity record for that pid during the time when this warning appears?

Thanks!

David J.

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