Orlando Andico wrote:
>
> On Sat, 7 Apr 2001, Rafael R. Sevilla wrote:
> ..
> > Postgres satisfies any decent definition of an RDBMS, however, it has
> > scalability problems and is slow when you compare it to a real enterprise
> > RDBMS like Oracle or DB/2.
>
> Not always!! on simple inserts and straight queries Pg is faster than
> Oracle.
> But its update functionality is about 2 orders of magnitude
> slower..
Correct me if I'm wrong, but I think you mean "twice as slow as an
insert". This would make sense, since in PgSQL versions up to 7.0 an
update is essentially an insert plus marking the old version of the row
as deleted.
Of course if you're updating a whole bunch of rows with this behavior,
performance goes straight to hell.
Starting with 7.1, PgSQL uses a Write Ahead Log which is the equivalent
to Oracle's Redo Log Buffer. I haven't had time to study the WAL
internals and behavior beyond what the docs say, but comparing it to
Oracle's fast COMMIT behavior, it *should* produce a marked improvement
in Postgres' overall write performance (at the expense of disk space --
a problem if you load in ~8GB of data like I did). Not that it affects
me much...right now most of my applications use straight INSERTs and
SELECTs 99% of the time.
Hopefully someone figures out how to do backup and recovery from the WAL
soon. That'd be a big help for me.
Brian "2 orders of magnitude != twice" Baquiran
_
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