> -----Original Message-----
> From: Bruno Wolff III [mailto:bruno@wolff.to]
> Sent: Wednesday, April 21, 2004 11:19 AM
> To: Philipp Buehler
> Cc: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] 7.3.4 on Linux: UPDATE .. foo=foo+1
> degrades massivly over time
>
>
> On Wed, Apr 21, 2004 at 19:52:15 +0200,
> Philipp Buehler <pb-pgsql-g@mlsub.buehler.net> wrote:
> >
> > While running
> > UPDATE banner SET counterhalf=counterhalf+1 WHERE
> BannerID=50 several
> > thousand times, the return times degrade (somewhat linear).
>
> This is to be expected. Postgres uses MVCC and everytime you
> do an update a new row is created.
>
> > A following VACCUM brings back return times to 'start' -
> but I cannot
> > run VACUUM any other minute (?). And it exactly vaccums as
> many tuples
> > as I updated.. sure thing:
>
> Why not? You only have to vacuum this one table. Vacuuming it
> once a minute should be doable.
Shouldn't the Database server be the entity that decides when vacuum is
needed?
Something is very, very strange about the whole PostgreSQL maintenance
model.
Oracle uses MVCC and I do not have to UPDATE STATISTICS constantly to
keep the system from going into the toilet.
Also, I should be able to do an update on every row in a database table
without causing severe problems. Every other database system I know of
does not have this problem.
If I have a million row table with a column called is_current, and I do
this:
UPDATE tname SET is_current = 0;
Horrible things happen.
Just an idea:
Why not recognize that more rows will be modified than the row setting
can support and actually break the command into batches internally?