RE: [GENERAL] Benchmarks

From: soundar rajan <psrajan(at)yahoo(dot)com>
To: Michael J Davis <michael(dot)j(dot)davis(at)tvguide(dot)com>, pgsql-general(at)hub(dot)org
Subject: RE: [GENERAL] Benchmarks
Date: 2000-01-07 15:13:24
Message-ID: 20000107151324.27698.qmail@web2103.mail.yahoo.com
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Can anyone hellp me out in creating a simple function
and a trigger ? When I create a function which
returns opaque, I get an error stating 'sql function
cannot return opaque'. When I create a function which
returns either int or varchar, I could create it, but,
on invoking the function while creating the trigger, I
get an error message stating the 'xxx' function must
return opaque. I get into a cycle of errors. Any
help to get out of the cycle (if possible with a small
example code ?). Thanks in advance.

--- Michael J Davis <michael(dot)j(dot)davis(at)tvguide(dot)com>
wrote:
> Maybe vacuum should be changed to automatically drop
> all indexes, vacuum,
> and re-create all indexes and stop trying to rebuild
> each index.
>
> > -----Original Message-----
> > From: Culberson, Philip
> [SMTP:philip(dot)culberson(at)dat(dot)com]
> > Sent: Thursday, January 06, 2000 1:58 PM
> > To: 'Bruce Momjian'; Dustin Sallings
> > Cc: The Hermit Hacker; pgsql-general(at)hub(dot)org
> > Subject: RE: [GENERAL] Benchmarks
> >
> > In his very insightful post last week, Mike
> Mascari pointed out that, on
> > tables with heavy insert/updates, it was much
> faster to drop the index,
> > vacuum analyze, and then rebuild the index. Maybe
> in vacuum there is a
> > specific inefficiency in what Mike coined
> "defragment"ing indexes.
> >
> > [Snip]
> >
> > 8. Not running VACUUM - PostgreSQL won't use
> indexes, or won't optimize
> > correctly unless the record count and dispersion
> estimates are up-to-date.
> > People have reported problems with running vacuum
> while under heavy load.
> > We
> > haven't seen it, but we run vacuum each night at
> 4:05 a.m. However, if you
> > perform a LARGE number of INSERTS/UPDATES, it is
> better for you to do the
> > following:
> >
> > DROP INDEX index_on_heavilty_used_table;
> > VACUUM ANALYZE;
> > CREATE INDEX index_on_heavily_used_table;
> >
> > Because VACUUM will sit there, and, row by row,
> essentially "defragment"
> > your indexes, which can take damn near forever for
> any number of updates
> > or
> > deletes greater than, say, 30,000 rows.
> >
> > [Snip]
> >
> > -----Original Message-----
> > From: Bruce Momjian
> [mailto:pgman(at)candle(dot)pha(dot)pa(dot)us]
> > Sent: Thursday, January 06, 2000 10:14 AM
> > To: Dustin Sallings
> > Cc: The Hermit Hacker; pgsql-general(at)hub(dot)org
> > Subject: Re: [GENERAL] Benchmarks
> >
> >
> > > Untrue, vacuum is *extremely* important for
> updating statistics.
> > > If you have a lot of data in a table, and you
> have never vacuumed, you
> > > might as well not have any indices. It'd be
> nice if you could seperate
> > > the stat update from the storage reclaim.
> Actually, it'd be nice if you
> > > could reuse storage, so that an actual vacuum
> wouldn't be necessary
> > unless
> > > you just wanted to free up disk space you might
> end up using again
> > anyway.
> > >
> > > The vacuum also doesn't seem to be very
> efficient. In one of my
> > > databases, a vacuum could take in excess of 24
> hours, while I've written
> > a
> > > small SQL script that does a select rename and a
> insert into select from
> > > that will do the same job in about ten minutes.
> This is a database that
> > > cannot lock for more than a few minutes.
> >
> > This is serious. Why would an INSERT / RENAME be
> so much faster. Are
> > we that bad with VACUUM?
> >
> > --
> > Bruce Momjian |
> http://www.op.net/~candle
> > maillist(at)candle(dot)pha(dot)pa(dot)us | (610)
> 853-3000
> > + If your life is a hard drive, | 830
> Blythe Avenue
> > + Christ can be your backup. | Drexel
> Hill, Pennsylvania 19026
> >
> > ************
> >
> > ************
>
> ************
>

=====
Thanks.
Soundar.
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