Re: Checkpointer split has broken things dramatically (was Re: DELETE vs TRUNCATE explanation)

On 07/23/2012 12:37 AM, David Fetter wrote:
> On Tue, Jul 17, 2012 at 06:56:50PM -0400, Tom Lane wrote:
>> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>>> On Mon, Jul 16, 2012 at 3:18 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>>> BTW, while we are on the subject: hasn't this split completely
>>>> broken the statistics about backend-initiated writes?
>>> Yes, it seems to have done just that.
>> This implies that nobody has done pull-the-plug testing on either
>> HEAD or 9.2 since the checkpointer split went in (2011-11-01),
>> because even a modicum of such testing would surely have shown that
>> we're failing to fsync a significant fraction of our write traffic.
>>
>> Furthermore, I would say that any performance testing done since
>> then, if it wasn't looking at purely read-only scenarios, isn't
>> worth the electrons it's written on. In particular, any performance
>> gain that anybody might have attributed to the checkpointer splitup
>> is very probably hogwash.
>>
>> This is not giving me a warm feeling about our testing practices.
> Is there any part of this that the buildfarm, or some other automation
> framework, might be able to handle?
>

I'm not sure how you automate testing a pull-the-plug scenario.

The buildfarm is not at all designed to test performance. That's why we
want a performance farm.

cheers

andrew