Re: JDBC delete not recovering space?

it's version 7.2.2 on RedHat 8.0 - sorry i forgot to mention that. and the
jdbc driver is pg73rc1jdbc3.jar.

john

---
john guthrie


----- Original Message -----
From: "Dave Cramer" <Dave@micro-automation.net>
To: "John Guthrie" <jguthrie@psynapsetech.net>
Cc: <pgsql-jdbc@postgresql.org>
Sent: Wednesday, April 23, 2003 11:54 AM
Subject: Re: [JDBC] JDBC delete not recovering space?


> What version of postres are you running, if it is 7.3.x only vacuum full
> will recover space
>
> Dave
> On Wed, 2003-04-23 at 11:45, John Guthrie wrote:
> > i am seeing some odd behavior and wonder if anyone can help me explain
it
> > and fix it...
> >
> > i've written a java task that runs in a thread and monitors disk space
on
> > the partition where i have my $PGDATA. if the space available drops
below a
> > certain level, i remove some old records ... and vacuum.
> >
> > the odd thing is that running via jdbc the space seems to not be
recovered.
> > example - if i start with 100,000 records of approximately 1K size and i
> > remove 50,000, using 'df' in another shell i see no space recovery. from
> > another shell, using psql, i run vacuum and again i see no gains.
> >
> > the really odd thing is that if i do this whole scenario in psql -
create
> > 100,000, delete the oldest 50,000, and vacuum - i *do* see the space
> > recovered.
> >
> > even better (or worse), if i do the whole test in java, verify that
little
> > or no space is recovered, then run psql and delete a single records and
> > vacuum, bam(!) i get a boatload of space back.
> >
> >  note that in the java task i explicitly set auto-commit to true and i
run
> > queries from psql that show results that reflect the deletions, so i
don't
> > see this as a transaction problem. also, if i shut down postgresql i see
the
> > correct (reduced) record count but still no space recovery. i can
restart
> > it, run psql, and vacuum, but still no space recovery... but if i then
> > delete a record and vacuum again, i get space, lots of space (i.e.
> > megabytes).
> >
> > any ideas anyone? thanks
> >
> > john
> >
> > ---
> > john guthrie
> > psynapse technologies
> >
> >
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> --
> Dave Cramer <Dave@micro-automation.net>
>