I will write a technical document about Sigres in a week.
Hideyuki
Bruce Momjian wrote:
> I am still unclear why sigres is better than a temporary file system. I
> relize your patch is faster, but what is about your patch that makes it
> faster.
>
> And if we were going to add such capability, we would name it based on
> what it does, rather than on a 'sigres' mode.
>
> ---------------------------------------------------------------------------
>
> Hideyuki Kawashima wrote:
>
>> Simon,
>>
>>
>>> Not checkpointing at all is not a good plan, since this will lead to an
>>> enormous build up of WAL files and a very long recovery time if the
>>> system does fail.
>>>
>> I appreciate your detailed comments.
>> Following your comments, I revised the problem.
>> Sigres-0.1.3 does checkpointings.
>>
>> In summary, the features of Sigres-0.1.3 are as follows.
>> 0: 10% faster than conventional PostgreSQL under tmpfs.
>> 1: Checkpointings are continually executed.
>> 2: Sigres mode is in default (the mode can be turned off via postgresql.conf).
>> 3: issue_xlog_sync is called only by bgwriter (continually, via
>> createcheckpoint)
>> 4: The entity of XLogWrite (_XLogWrite in my code) is called by both
>> backends and a bgwriter.
>> For each backend, _XLogWrite is called only via AdvanceXLInsertBuffer.
>> For a bgwriter, _XLogWrite is called via CreateCheckPoint.
>>
>> Please try it if you have interest.
>> http://sourceforge.jp/projects/sigres/
>>
>> Again, I really appreciate beneficial comments from this community !
>>
>> Regards,
>>
>> -- Hideyuki
>>
>> --
>> Hideyuki Kawashima (Ph.D.)
>> University of Tsukuba
>> Assistant Professor
>>
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>
>
--
Hideyuki Kawashima (Ph.D), University of Tsukuba,
Graduate School of Systems and Information Engineering
Assistant Professor, TEL: +81-29-853-5322