Re: Fast Refresh of Materialized views

It may be that your fast refresh is actually doing a lot of work. This would happen if many rows in the source table were changed. If 99% of the rows changed, then a complete refresh will be faster, because you don't have the added overhead of reading the logs to determine which rows to refresh - you just refresh them all.

If only 1% of the rows changed then the fast refresh will indeed be fast - faster than a complete refresh.

Somewhere in between there's a break even point. It may be that many rows have changed - enough to take you past the break even point.

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Tuesday, August 28, 2001 3:00 PM

> We've noticed that our fast refresh takes longer than complete refresh -
and
> that's puzzling .We have MV logs based on the PK of the FACT table - and
the
> MV's are JOIN ONLY .
> Any suggestions would be welcome !
>
> vikas
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Vikas Kawatra
> INET: VKawatra_at_innoventry.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Greg Moore
  INET: sqlgreg_at_pacbell.net

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