Re: [PATCH] A crash and subsequent recovery of the master can cause the slave to get out-of-sync

Поиск
Список
Период
Сортировка
От Bruce Momjian
Тема Re: [PATCH] A crash and subsequent recovery of the master can cause the slave to get out-of-sync
Дата
Msg-id 200704270235.l3R2ZeW02321@momjian.us
обсуждение исходный текст
Ответ на [PATCH] A crash and subsequent recovery of the master can cause the slave to get out-of-sync  ("Florian G. Pflug" <fgp@phlo.org>)
Список pgsql-hackers
Your patch has been added to the PostgreSQL unapplied patches list at:
http://momjian.postgresql.org/cgi-bin/pgpatches

It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.

---------------------------------------------------------------------------


Florian G. Pflug wrote:
> Hi
> 
> I believe I have discovered the following problem in pgsql 8.2 and HEAD,
> concerning warm-standbys using WAL log shipping.
> 
> The problem is that after a crash, the master might complete incomplete
> actions via rm_cleanup() - but since it won't wal-log those changes,
> the slave won't know about this. This will at least prevent the creation
> of any further restart points on the slave (because safe_restartpoint)
> will never return true again - it it might even cause data corruption,
> if subsequent wal records are interpreted wrongly by the slave because
> it sees other data than the master did when it generated them.
> 
> Attached is a patch that lets RecoveryRestartPoint call all
> rm_cleanup() methods and create a restart point whenever it encounters
> a shutdown checkpoint in the wal (because those are generated after
> recovery). This ought not cause a performance degradation, because
> shutdown checkpoints will occur very infrequently.
> 
> The patch is per discussion with Simon Riggs.
> 
> I've not yet had a chance to test this patch, I only made sure
> that it compiles. I'm sending this out now because I hope this
> might make it into 8.2.4.
> 
> greetings, Florian Pflug


> 
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster

--  Bruce Momjian  <bruce@momjian.us>          http://momjian.us EnterpriseDB
http://www.enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +


В списке pgsql-hackers по дате отправления:

Предыдущее
От: Bruce Momjian
Дата:
Сообщение: Re: Background LRU Writer/free list
Следующее
От: Tom Lane
Дата:
Сообщение: Re: elog(FATAL) vs shared memory