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Re: allowing wal_level change at run time - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: allowing wal_level change at run time
Date
Msg-id CANP8+jJWKkcVF-CuSEAR9v_sCQuVtOWEvqXgHfFrNPbCwVqOaA@mail.gmail.com
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In response to Re: allowing wal_level change at run time  (Andres Freund <andres@anarazel.de>)
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On 18 August 2015 at 18:46, Andres Freund <andres@anarazel.de> wrote:
 
ISTM that it's not too hard to
a) make archive_mode PGC_SIGHUP
b) make wal_level PGC_SIGHUP

+1
 
c) automatically increase wal_level to logical whenever a logical
   replication slot is defined

-1

It would be easier to just have wal_level = logical always, but allow it to be set lower if desired.

Increasing wal_level dynamically might otherwise happen too late.
 
it seems considerably harder to

d) make max_wal_senders PGC_SIGHUP
e) make max_replication_slots PGC_SIGHUP

because they need shmem, locks, and everything.


Therefore I propose something slightly different:

We change the default of max_wal_senders, max_replication_slots, to some
reasonably high setting

Agreed, I suggest 8 as the default for each.
 
--
Simon Riggs                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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