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Re: Materialized Views, Refresh Groups and DDMS_REFRESH Procedures

From: Richard Foote <richard.foote_at_bigpond.com>
Date: Mon, 8 Jul 2002 22:13:02 +1000
Message-ID: <MefW8.30617$Hj3.92566@newsfeeds.bigpond.com>


Hi Markus,

The use of refresh groups is that by grouping MVs together and refreshing them together ensures that all grouped MVs are "consistent" after the refresh. This eliminates RI issues between the related MVs. In my view it's incorrect to view the refresh as being ONE transaction, but rather the applying of a collection of transactions to a specific point in time.

There may also be performance benefits in applying one large group of changes than applying the changes separately (it depends).

Have a good read of the Replication manual, it's all explained in there.

Good Luck

Richard
"Markus Kunze" <markus.kunze_at_sdm.de> wrote in message news:1103_1026126341_at_news.sdm.de...
> Hi,
>
> I have defined MVs (A, B, C) on tables of my database. The mvs are defined
with FAST refresh option and with a given period NEXT 'SYSDATE+320/86400'.
> I want the MVs to update periodically and the update transaction must be
atomic.
> According to Oracle Docs I executed the following statement:
>
> BEGIN
> DBMS_SNAPSHOT.REFRESH (
> 'A,B,C'
> ,NULL
> ,NULL
> ,TRUE
> ,FALSE
> ,1
> ,0
> ,0
> ,TRUE);
> END;
> /
>
> This means my mvs will refresh FAST (their own refresh option) every 5
minutes in ONE transaction.
>
> But I also found information about refresh groups in the oracle docs and I
don't understand what they are used for.
>
> Can anyone help me? What is the use for Refresh Groups?
>
> Is it better to group my mvs first and define the refresh option on the
refresh group?
>
> Thanks in advance
>
> Markus
>
>
Received on Mon Jul 08 2002 - 07:13:02 CDT

Original text of this message

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