SV: Problem with pg_notify / listen

[Gustavsson Mikael <mikael.gustavsson@xxxxxxx>]

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

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Från: David G. Johnston <david.g.johnston@xxxxxxxxx>
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@xxxxxxx> 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.