Re: Experimental patch for inter-page delay in VACUUM

Bruce Momjian <pgman@candle.pha.pa.us>

From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Neil Conway <neilc@samurai.com>
Cc: Jan Wieck <JanWieck@yahoo.com>, Tom Lane <tgl@sss.pgh.pa.us>, Ang Chin Han <angch@bytecraft.com.my>, Christopher Browne <cbbrowne@acm.org>, pgsql-hackers@postgresql.org
Date: 2003-11-10T20:36:36Z
Lists: pgsql-hackers
Neil Conway wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Another idea --- if fsync() is slow because it can't find the dirty
> > buffers, use write() to write the buffers, copy the buffer to local
> > memory, mark it as clean, then open the file with O_SYNC and write
> > it again.
> 
> Yuck.

This idea if mine will not even work unless others are prevented from
writing that data block while I am fsync'ing from local memory --- what
if someone modified and wrote that block before my block did its fsync
write?  I would overwrite their new data.  It was just a crazy idea.

-- 
  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, Pennsylvania 19073