RE: redo curiosity

http://gplivna.eu/papers/mat_views_search.htm

Allowing the create or replace syntax and the application of synonyms to things beyond just tables was one of the key things Oracle's VLDB group and Oracle agreed on way back in the early 1990's as an enhancement for scalability. I love to see people make good use of it.

With or without partitioning it can also be used to direct inserts into a particular segment, for example if analysis queries through yesterday are good enough, so that analysis queries do not compete with OLTP inserts.

The key is that once the previous query is resolved by name through the synonym, changing the synonym does not affect the running query, but you get a new parse for queries after the create or replace synonym.

As long as the change for the synonym is at a reasonable grain of time the parse storms are minimal but the ability to isolate "reader only" queries from the changing segments can really take a load off undo. And, as in the current case off redo as well.

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Gints Plivna
Sent: Friday, February 19, 2010 3:49 PM
To: Chris.Stephens_at_adm.com
Cc: maureen.english_at_alaska.edu; Oracle-l_at_freelists.org Subject: Re: redo curiosity

2010/2/19 Stephens, Chris <Chris.Stephens_at_adm.com>:
> There is the 3rd alternative the Mark proposed which I'm going to be doing
at my current place of employment.  I have no idea why I didn't think of this before.
>
> That would be messing with synonyms and keeping multiple copies of
materialized views.

Mess is not so big as probably initially seems. I have done it and even described quite precise in my article here http://gplivna.eu/papers/mat_views_search.htm

For refresh process see chapter Alternate refresh process of materialized views

Gints Plivna
http://www.gplivna.eu

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