Re: synchronous_commit and remote_write

On 9 May 2012 13:48, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Wed, May 9, 2012 at 7:29 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>> Let me point out that our documentation says nothing about it being
>> written to the kernel --- it just says "has received the commit record
>> of the transaction to memory."
>
> Maybe remote_receive would be better.  If we're actually writing it
> back to the kernel before acknowledging the commit, that seems like an
> implementation defect more than anything else, since it does not -
> AFAICS - provide any additional, useful guarantee.

It does provide an additional guarantee, but I accept you personally
may not find that useful.

If the docs don't describe it well enough, then we can change the docs.

> Another thing I've been wondering is whether, perhaps, we ought to
> keep synchronous_commit tri-valued: on/local/off, and have a separate
> GUC for synchronous_replication_mode.  It's a bit arbitrary that "on"
> happens to mean remote fsync rather than remote write/receive.

You mean the way it originally was? I would agree.

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