Recovery conflict due to buffer pins - Mailing list pgsql-admin

From Nikhil Shetty
Subject Recovery conflict due to buffer pins
Date
Msg-id CAFpL5Vxm4B2885NqXjUmZL7zpCGgL2dy=AGtOe9F31J0X+oz5Q@mail.gmail.com
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Responses Re: Recovery conflict due to buffer pins
List pgsql-admin
Hi,

PostgreSQL version - 11.7

We are seeing using few queries to fetch data from standby for monitoring but we often see that the query is cancelled due to 'conflict with recovery'.

Example:

ERROR: canceling statement due to conflict with recovery

2022-06-12 04:30:01 UTC [3594]: [5-1] user=<user>,db=postgres,app=<app>,client=127.0.0.1DETAIL:  User was holding shared buffer pin for too long.

2022-06-12 04:30:01 UTC [3594]: [6-1] user=<user>,db=postgres,app=<app>,client=127.0.0.1STATEMENT:  SET statement_timeout = 30000; SELECT 'dbsize_bytes', COALESCE(sum(pg_database_size(datname)),0) FROM pg_stat_database where datname NOT IN ('postgres','template0','template1');




2022-06-12 04:30:01 UTC [3324]: [3-1] user=<user>,db=postgres,app=<app>,client=127.0.0.1ERROR:  canceling statement due to conflict with recovery

04:30:01 UTC [3324]: [4-1] user=<user>,db=postgres,app=<app>,client=127.0.0.1DETAIL:  User was holding shared buffer pin for too long.

04:30:01 UTC [3324]: [5-1] user=<user>,db=postgres,app=<app>,client=127.0.0.1STATEMENT:  SELECT 'tuple_returned', sum(tup_returned)  FROM pg_stat_database;



I have verified that there is a vacuum operation happening at the same time on primary.


We have set below parameters in standby


hot_standby_feedback = on

max_standby_streaming_delay = 0


How can we avoid this error on standby? 


Regards,

Nikhil


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