RE: redo curiosity
- From: "Mark W. Farnham" <mwf@xxxxxxxx>
- To: <gints.plivna@xxxxxxxxx>, <Chris.Stephens@xxxxxxx>
- Date: Fri, 19 Feb 2010 17:03:01 -0500
Very nice writeup, Gints.
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@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Gints Plivna
Sent: Friday, February 19, 2010 3:49 PM
To: Chris.Stephens@xxxxxxx
Cc: maureen.english@xxxxxxxxxx; Oracle-l@xxxxxxxxxxxxx
Subject: Re: redo curiosity
2010/2/19 Stephens, Chris <Chris.Stephens@xxxxxxx>:
> 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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