Re: Use of rollback segments

See embedded :

lrako_at_hotmail.com wrote in message <6rh7hp$749$1_at_nnrp1.dejanews.com>...
>Hi ,
>
>I'm currently working on a conversion application on Oracle 7.3/NT.
>
>It does a lot of heavy transactions (updates 515000 rows many times,
>deletes..) and takes about 5 hours to run completely Recently we had an
error
>' failed to extend rollback segment' or something like that. After a few
>investigations, we created a new rollback segment but without having any
clue
>of what would be the outcome of it. Eventually, we got rid of the error but
>still in a blur regarding the use of a rollback segment.
>
>WHAT DOES EXACTLY DO A ROLLBACK SEGMENT ?
I'm no expert on databases, but rollback segment(s) are used to support transactions so that you can rollback (undo) any sql statements performed since the last 'commit'.

>
>I noticed that we have now 8 rollback segments of various sizes, ranging
from
>20M to 160M in a single RBS tablespace.
>
>IS'N IT TOO MUCH ? WHAT ARE RULES IN MANAGING ROLLBACK SEGMENTS ??
>

If you want to delete 515000 rows you've got to have rollback segment(s) big enough to keep all data you wish to delete (a bit cryptic, sorry). On the other hand, if you want to delete ALL data from a table there is a specific command to do that which doesn't use rollback segment (truncate, I believe).

H.T.H. // Johan Received on Thu Aug 20 1998 - 08:56:59 CDT