Re:VACUUM: Nonremovable rows due to wal sender process - Mailing list pgsql-performance

From Sergei Kornilov
Subject Re:VACUUM: Nonremovable rows due to wal sender process
Date
Msg-id 1138801641327472@sas2-4fe1bb3c0a49.qloud-c.yandex.net
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In response to VACUUM: Nonremovable rows due to wal sender process  (Steve Nixon <inverasln@gmail.com>)
Responses Re: VACUUM: Nonremovable rows due to wal sender process  (Steve Nixon <inverasln@gmail.com>)
List pgsql-performance
Hello
This is exactly the reason why you need to track the age of the oldest transaction on the primary itself and on every
replicathat has hot_standby_feedback = on. By default hot_standby_feedback is disabled.
 

> Is there anything I can do short of shutting down and restarting the primary (production system) that would allow the
backend_xminto move forward?
 

You need to investigate this replica. Not a primary database. What transactions are in progress? Is it reasonable? Is
hot_standby_feedbackreally needed here and is it reasonable to pay for its impact across the entire cluster?
 
In my practice, hot_standby_feedback = on is only needed on replicas intended for fast OLTP queries. And where any long
requestsare prohibited. 
 

regards, Sergei



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