Re: Proposal for 9.1: WAL streaming from WAL buffers

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Proposal for 9.1: WAL streaming from WAL buffers
Date: 2010-06-11 14:24:03
Message-ID: AANLkTilVovQVAmiwvIaaffdDIK83hnX35i1gU-mcGywA@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Fri, Jun 11, 2010 at 9:57 AM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> On Fri, Jun 11, 2010 at 10:22 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> On Fri, Jun 11, 2010 at 9:14 AM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>>> Thought? Comment? Objection?
>>
>> What happens if the WAL is streamed to the standby and then the master
>> crashes without writing that WAL to disk?
>
> What are you concerned about?
>
> I think that the situation would be the same as 9.0 from users' perspective.
> After failover, the transaction which a client regards as aborted (because
> of the crash) might be visible or invisible on new master (i.e., original
> standby). For now, we cannot control that.

I think the failover case might be OK. But if the master crashes and
restarts, the slave might be left thinking its xlog position is ahead
of the xlog position on the master.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2010-06-11 14:31:30 Re: Proposal for 9.1: WAL streaming from WAL buffers
Previous Message Fujii Masao 2010-06-11 13:57:48 Re: Proposal for 9.1: WAL streaming from WAL buffers