RE: Runtime for deleteing lots of records

In Oracle it's a manual process.  As part of "tuning and maintenance" you
may have to rebuild indexes to keep on top of table updates.  Depending on
whether you're using cost-based or rules-based access methods you also may
have to manually run processes to update database statistics so that queries
know how to find data efficiently.

When we were running Lawson on the AS/400, for example, we would run weekly
RGZPFM's on a few tables, but it was overkill.  It took 2 or 3 hours, and we
were really dealing with storage management, not performance.  Once we
changed a few files to RGZDLT(*YES) it was moot.  Moving the same system to
Unix/Oracle we have to run half day of weekly database maintenance -- mostly
index rebuilds.  If we fail to run the maintenance the system will grind to
a halt by Wednesday or Thursday.

High volumes of deletes will create crippling inefficiencies in indexes.
High volumes of inserts will likely cause database statistics to be
inaccurate for cost-based optimizer performance.

It's a whole 'nuther world...

-----Original Message-----
From: Vern Hamberg [mailto:vhamberg@centerfieldtechnology.com]
Sent: Tuesday, February 11, 2003 12:11 PM
To: Midrange Systems Technical Discussion
Subject: RE: Runtime for deleteing lots of records


Ah, right, Jim. It's something the system determines the need of - as 
usual, the 400 does a lot for us. But it still needs to be done, and Leif 
suggested that it's done often. Is it a manual process in other RDBMS'?

Vern

At 09:40 AM 2/11/2003 -0600, you wrote:
>I'm not sure if I understand the question.  I've never had to manually
>rebuild or update an index on the AS/400 to deal with high volumes of
>deleted rows.
>
>-Jim
>
>-----Original Message-----
>From: Vern Hamberg [mailto:vhamberg@centerfieldtechnology.com]
>Sent: Monday, February 10, 2003 6:58 PM
>To: Midrange Systems Technical Discussion
>Subject: RE: Runtime for deleteing lots of records
>
>
>Jim, doesn't the 400 also balance the index tree from time to time? If it's
>smart enough only to remove entries in the index for deleted records,
>eventually the tree could get severely skewed, I would think, and require
>balancing.
>
>Vern