Re: Re: a "huge" table with small rows and culumns

Hi,

AFAIK when an entity EJB is instantiated it will be read from the DB.
Similarly, when it is destroyed, it will be serialized to the DB again.
Thus an update, which causes your table to grow.

Maarten

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Maarten Boekhold, maarten.boekhold@reuters.com

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Feng Xue <feng@axe.net.au>
18/12/00 23:55


        To:     pgsql-general@postgresql.org
        cc:     (bcc: Maarten Boekhold/PAL/US/Reuters)
        Subject:        [GENERAL] Re: a "huge" table with small rows and culumns
        Header: Internal Use Only



hi, Adam and all,

Thanks for your reply, but the table has not been updated or deletes
constantly, it is only looked
up frequently by other programs.

Actually this table is accessed by JDBC from a Jonas EJB entity bean. and
it is constantly looked
up, and after I
use "ls -al" I can find that in
/usr/local/pgsql/data/base/The_data_base_name/The_huge_table
timestamp is updated as the user access that table. I have no idea why the
timestamp is keeping
updated and the size is keeping growing even through there are no
updateing and the rows are only
50.

Thanks for the suggestion.

Cheers

feng

feng@axe.net.au
Axe Online Pty. Ltd.
T (02) 9437 0920
F (02) 9437 0261



----- Original Message -----
From: "Adam Lang" <aalang@rutgersinsurance.com>
To: <pgsql-general@postgresql.org>
Sent: Tuesday, December 19, 2000 9:06 AM
Subject: Re: a "huge" table with small rows and culumns


> Do you do a lot of updates and/or deletes?  If so, you need to VACUUM
your
> database.  When rows are modified, they are not actually deleted.  They
are
> just flagged to be ignored.
>
> Vacuum cleans up the rows.
>
> Adam Lang
> Systems Engineer
> Rutgers Casualty Insurance Company
> http://www.rutgersinsurance.com
> ----- Original Message -----
> From: "Feng Xue" <feng@axe.net.au>
> To: <pgsql-general@postgresql.org>
> Sent: Monday, December 18, 2000 4:59 PM
> Subject: [GENERAL] a "huge" table with small rows and culumns
>
>
> > hi,
> >
> > I have been a postgres user for serveral months. But recently I find a
> "mysterious" things
> > in my /usr/local/pgsql/data/base/The_Database_Name/The_table_name.
> >
> > In a particular table name "fred" there are only 50 rows and 13
columns.
> The column types are int,
> > float, varchar, where
> > varchar's size is restricted to 50. But its size of
> > /usr/local/pgsql/data/base/The_Database_Name/fred is more than 20M,
and
> it keeps growing while the
> > rows number is still 50.
> >
> > I am using linux (slackware), with postgres as database, Jonas as EJB
> server, Tomcat and apache
> > as webserver, the "fred" table is constantly looked up (no updated) by
the
> user.
> >
> > Thanks in advance for any suggestions.
> >
> > Cheers
> >
> > Feng
>
>




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