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From: Marko Tiikkaja <[email protected]>
To: [email protected]
Subject: hot_standby_feedback and max_standby_archive_delay
Date: Fri, 17 Jan 2014 00:38:13 +0100
Message-ID: <[email protected]> (raw)
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Hi,

Myself and others found this statement in the documentation about 
$SUBJECT very confusing: "max_standby_archive_delay must be kept large 
in this case, because delayed WAL files might already contain entries 
that conflict with the desired standby queries.".  After a chat with 
Andres I've tried to make it clearer what said statement tries to convey.

Did I succeed?


Regards,
Marko Tiikkaja

*** a/doc/src/sgml/high-availability.sgml
--- b/doc/src/sgml/high-availability.sgml
***************
*** 1810,1818 **** if (!triggered)
      situation will be no worse than if the standby queries were running
      directly on the primary server, and you are still getting the benefit of
      off-loading execution onto the standby.
!     <varname>max_standby_archive_delay</> must be kept large in this case,
!     because delayed WAL files might already contain entries that conflict with
!     the desired standby queries.
     </para>
  
     <para>
--- 1810,1820 ----
      situation will be no worse than if the standby queries were running
      directly on the primary server, and you are still getting the benefit of
      off-loading execution onto the standby.
!     If a standby loses connectivity to the master, its
!     <varname>hot_standby_feedback</> value is not respected by the master until
!     the connection has been restored.  If the slave wishes to continue
!     executing queries in that case, its <varname>max_standby_archive_delay</>
!     should be kept large.
     </para>
  
     <para>


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Attachments:

  [text/plain] hot_standby_feedback.patch (1.1K, 2-hot_standby_feedback.patch)
  download | inline diff:
*** a/doc/src/sgml/high-availability.sgml
--- b/doc/src/sgml/high-availability.sgml
***************
*** 1810,1818 **** if (!triggered)
      situation will be no worse than if the standby queries were running
      directly on the primary server, and you are still getting the benefit of
      off-loading execution onto the standby.
!     <varname>max_standby_archive_delay</> must be kept large in this case,
!     because delayed WAL files might already contain entries that conflict with
!     the desired standby queries.
     </para>
  
     <para>
--- 1810,1820 ----
      situation will be no worse than if the standby queries were running
      directly on the primary server, and you are still getting the benefit of
      off-loading execution onto the standby.
!     If a standby loses connectivity to the master, its
!     <varname>hot_standby_feedback</> value is not respected by the master until
!     the connection has been restored.  If the slave wishes to continue
!     executing queries in that case, its <varname>max_standby_archive_delay</>
!     should be kept large.
     </para>
  
     <para>

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