Re: Background writer process - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Background writer process
Date
Msg-id 200311132210.hADMAnK26464@candle.pha.pa.us
Whole thread Raw
In response to Re: Background writer process  (Kurt Roeckx <Q@ping.be>)
Responses Re: Background writer process  (Jan Wieck <JanWieck@Yahoo.com>)
List pgsql-hackers
Kurt Roeckx wrote:
> On Thu, Nov 13, 2003 at 04:35:31PM -0500, Jan Wieck wrote:
> > For sure the sync() needs to be replaced by the discussed fsync() of 
> > recently written files. And I think the algorithm how much and how often 
> > to flush can be significantly improved. But after all, this does not 
> > change the real checkpointing at all, and the general framework having a 
> > separate process is what we probably want.
> 
> Why is the sync() needed at all?  My understanding was that it
> was only needed in case of a checkpoint.

He found that write() itself didn't encourage the kernel to write the
buffers to disk fast enough.  I think the final solution will be to use
fsync or O_SYNC.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


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