Re: relaxing sync commit if no WAL written (was Re: unlogged tables)

On Sun, Dec 19, 2010 at 3:08 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On Sun, 2010-12-19 at 07:33 -0500, Robert Haas wrote:
>> On Sun, Dec 19, 2010 at 7:01 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> > On Fri, 2010-12-17 at 13:35 -0500, Robert Haas wrote:
>> >
>> >> I'm
>> >> thinking it makes sense to commit this part first.
>> >
>> > This will break Hot Standby, as previously explained. Don't.
>>
>> Uh, why?  Skipping the commit record altogether would do that, but
>> this patch doesn't do that.
>
> I was looking for XLogStandbyInfoActive()
>
> It isn't there, so you're either breaking HS or missing a possible
> optimisation. Having said that, it would be useful to be able to assume
> that all xids appear in the log, for diagnostic purposes.
>
> So I now agree with the way you've coded it.

OK, thanks. Committed. Note that there is also a long comment in
there which includes a discussion of the issues relating to Hot
Standby. Hopefully that's clear enough to prevent anyone from getting
too clever with this in the future.

--
Robert Haas
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