Subject Getting garbage info from the database
Author Peter Ypenburg
Hi There,

We have a client server application that connects to the database and
allows the user to view and change some data. At night we have programs
that run and import new data (from host systems like SAP etc) and does
many, many calculations and manipulations of the data so that when the
user connects the next day he could see the results of last nights
import and data calculations. Our application is mission critical to the
client, the next day he can not do his work until our overnight
processes are done.

One of the things we have that is killing us at the moment (we suspect)
is garbage. As these processes that run over night (and creates garbage)
has a limited time window in which to finish. If an overnight batch
blows out by 6 hours the client is stuffed and furious. This makes our
lives very difficult as we are forever trying to fight fires.

We need help so here are a couple of questions:

1.) Can some one point me to a in depth tutorial about garbage in the

2.) How do I find out at any stage what is the state of the amount of
garbage in the database?

3.) How do I find out where (what tables) the garbage is affecting the

4.) What is the best way to get rid on the garbage when there is
garbage? We currently fire <select count(*) from TableName> to the
database to get rid of garbage on a specific table.

5.) Why does garbage sometimes make the database grind to a halt?

6.) Sometimes garbage collection is quick (10 min) and sometimes it
takes long (12 hours), why?

Thank you,

Peter Ypenburg
AGM Product Development
Barloworld Optimus

Life is beautiful.

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