Re: Initial 9.2 pgbench write results

----- Цитат от Robert Haas (robertmhaas(at)gmail(dot)com), на 28.02.2012 в 19:25 -----

> On Tue, Feb 28, 2012 at 11:36 AM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
>> How hard would it be to dummy up a bgwriter which, every time it wakes
>> up, it forks off a child process to actually do the write, and then
>> the real one just waits for the child to exit?  If it didn't have to
>> correctly handle signals, SINVAL, and such, it should be just a few
>> lines of code, but I don't know how much we can ignore signals and
>> such even just for testing purposes.  My thought here is that the
>> kernel is getting in a snit over one process doing all the writing on
>> the system, and is punishing that process in a way that ruins things
>> for everyone.
>
> I would assume the only punishment that the kernel would inflict would
> be to put the bgwriter to sleep. That would make the bgwriter less
> effective, of course, but it shouldn't make it worse than no bgwriter
> at all. Unless it does it some really stupid way, like making
> bgwriter sleep while it holds some lock.
>
> But maybe I'm missing something - what do you have in mind?
>
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> Robert Haas
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--
Luben Karavelov