Re: [9.3 bug] disk space in pg_xlog increases during archive recovery

On Thu, Aug 1, 2013 at 7:37 AM, MauMau <maumau307(at)gmail(dot)com> wrote:
> From: "Fujii Masao" <masao(dot)fujii(at)gmail(dot)com>
>
>> - if (source == XLOG_FROM_ARCHIVE)
>> + if (source == XLOG_FROM_ARCHIVE &&
>> + StandbyModeRequested && AllowCascadeReplication())
>>
>> I think that the condition of StandbyModeRequested should be removed
>> because someone might want to set up the cascade standby from the standby
>> of warm-standby configuration.
>
>
> Fixed and attached the revised patch.
>
> However, isn't StandbyRequested true (= standby_mode set to on) to enable
> warm standby?

We can set up warm-standby by using pg_standby even if standby_mode = off.

> I'm afraid people set max_wal_senders>0 and hot_standby=on
> even on the primary server to make the contents of postgresql.conf identical
> on both the primary and the standby for easier configuration. If so, normal
> archive recovery (PITR, not the standby recovery) would face the original
> problem -- unnecessary WAL accumulation in pg_xlog/. So I'm wonder if
> AllowCascadeReplication() is enough.

One idea is to add new GUC parameter like enable_cascade_replication
and then prevent WAL file from being kept in pg_xlog if that parameter is off.
But we cannot apply such change into the already-released version 9.2.

Regards,

--
Fujii Masao