Re: Disabling WAL for bulk data loads

On Fri, Sep 09, 2005 at 01:14:28PM -0400, Chris Browne wrote:
> kevinrkeith(at)hotmail(dot)com ("Kevin Keith") writes:
> > I am coming from an Oracle background - which in the case of bulk data
> > loads there were several options I had where I could disable writing
> > to the redo log to speed up the bulk data load (i.e. direct load, set
> > the user session in no archive logging, set the affected tables to
> > have no logging).
> >
> > I know the COPY command is one option - however it appears the data
> > would need to be in formatted file in order to use it correct? I want
> > to avoid writing a new file out for the COPY command and loading that.
>
> The options get a bit better in 8.1, as the COPY command supports some
> more format options.
>
> But you'll DEFINITELY get a big boost if you can format things so COPY
> can work for you.
>
> > What other options does Postgres 7.4 provide which would allow data
> > loads to bypass writing to the WAL? I don't need to have this enabled
> > - because in the event of a database crash, I would simply reload the
> > data from the source files as recovery.
>
> Arguably you could turn "fsync = off" in postgresql.conf; there is
> regrettably the increased risk that a crash would trash the ENTIRE
> database, not just the recently-loaded data.

Actually, it may trash all of the databases on that cluster!

>
> It's somewhat regrettable that you can't turn off logging just for a
> single transaction's context; that would probably be the ideal for
> this...
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--
Tim Goodaire 416-673-4126 tgoodair(at)ca(dot)afilias(dot)info
Database Administrator, Afilias Canada Corp.