Re: massive delete

Hi.
  Are these big tables? How about Foreign Keys. Is it cascading the deletes to/from other tables?

 If it's been awhile, you may want to rebuild your indexes on the table and see if that helps.
let me know.

Olivier Bercovitz wrote:
>
> Hello George,
> do you wirk with cost-based optimizer ?
> Try to analyze your table just before delete the rows
> or
> try to delete statistics (with analyze table xxxx delete statistics;)
> both tries with optimizer_mode=choose
>
> Tell me the result please, I am interested by it
>
> Regards. Olivier
>
> George Meltser wrote:
>
> > I hope somebody can help me.
> > At night we have to replace about 20% of our data.
> > First we delete the rows then insert the new ones.
> > Delete may take any time from 2 to 4 hours.
> > I did SQL_TRACE many times and was really surprised that amount of time it
> > takes to delete the same number of rows from the same table changes from day
> > to day dramatically, let's say from 3 min to 28 min or from 54 min to 22.
> > The load on the server is the same at this time.
> > What may cause those delays?
> > None of these tables have chained rows, all are stored in 1 extent, i have
> > not changed indexes on them for about 6 months.
> > Is it Rollback segment shrinking?
> > Thanx in advance,
> > Regards,
> > George
Received on Mon Apr 06 1998 - 00:00:00 CDT