Re: How to start slave after pg_basebackup. Why min_wal_size and wal_keep_segments are duplicated - Mailing list pgsql-general

From Andrus
Subject Re: How to start slave after pg_basebackup. Why min_wal_size and wal_keep_segments are duplicated
Date
Msg-id 102C5FA16F1549659B393B6A824B561F@dell2
Whole thread Raw
In response to Re: How to start slave after pg_basebackup. Why min_wal_size andwal_keep_segments are duplicated  (Adrian Klaver <adrian.klaver@aklaver.com>)
Responses Re: How to start slave after pg_basebackup. Why min_wal_size andwal_keep_segments are duplicated
Re: How to start slave after pg_basebackup. Why min_wal_size andwal_keep_segments are duplicated
List pgsql-general
Hi!

>I'm guessing are looking for:
>https://www.postgresql.org/docs/12/runtime-config-replication.html
>26.2.6. Replication Slots
>Replication slots provide an automated way to ensure that the master 
>does not remove WAL segments until they have been received by all 
>standbys, and that the master does not remove rows which could cause a 
>recovery conflict even when the standby is disconnected.

Using replication slot can cause pg_wal directoy to occupy all free disk space and after that server stop respondig.

>This is spelled out here:
> https://www.postgresql.org/docs/12/warm-standby.html#STREAMING-REPLICATION
>"If you use streaming replication without file-based continuous 
>archiving, the server might recycle old WAL segments before the standby 
>has received them. If this occurs, the standby will need to be 
>reinitialized from a new base backup. You can avoid this by setting 
>wal_keep_segments to a value large enough to ensure that WAL segments 
>are not recycled too early, or by configuring a replication slot for the 
>standby. 

Will wal_keep_segments  keep segments also if named replication slot is lot used ?

Andrus.



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