Re: Disable page writes when fsync off, add GUC

Michael Paesold wrote:
> Bruce Momjian wrote:
>
> > Bruce Momjian wrote:
> >> This also adds a full_page_writes GUC to turn off page writes to WAL.
> >> Some people might not want full_page_writes.
> >
> > Fsync linkage removed, patch attached and applied.
>
> ...
> +     When this option is on, the <productname>PostgreSQL</> server
> +     writes full pages to WAL when they first modified after a checkpoint
> +     so full recovery is possible.
>
> I believe this should be "when they _are_ first modified after".
>
> Perhaps you should also mention power failure, not only an operating system
> crash as disaster scenario, even if the latter includes the former.
>

Thanks.  Done.

--
  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
Index: doc/src/sgml/runtime.sgml
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RCS file: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v
retrieving revision 1.336
diff -c -c -r1.336 runtime.sgml
*** doc/src/sgml/runtime.sgml    5 Jul 2005 23:18:09 -0000    1.336
--- doc/src/sgml/runtime.sgml    6 Jul 2005 14:40:15 -0000
***************
*** 1705,1715 ****

         <para>
          When this option is on, the <productname>PostgreSQL</> server
!         writes full pages to WAL when they first modified after a checkpoint
!         so full recovery is possible. Turning this option off might lead
!         to a corrupt system after an operating system crash because
!         uncorrected partial pages might contain inconsistent or corrupt
!         data. The risks are less but similar to <varname>fsync</>.
         </para>

         <para>
--- 1705,1716 ----

         <para>
          When this option is on, the <productname>PostgreSQL</> server
!         writes full pages to WAL when they are first modified after a
!         checkpoint so full recovery is possible. Turning this option off
!         might lead to a corrupt system after an operating system crash
!         or power failure because uncorrected partial pages might contain
!         inconsistent or corrupt data. The risks are less but similar to
!         <varname>fsync</>.
         </para>

         <para>