Replacing a view with selects on it

From: jaromir nemec <jaromir_at_db-nemec.com>
Date: Sun, 16 May 2004 17:49:31 +0200
Message-ID: <011f01c43b5d$6438ae10$3c02a8c0@JARAWIN>

H,  

There is a common strategy in some DSS systems to refresh the data by replacing the access views (they are repointed to the new version of data). In case there is defined a loading window (with no access) I guess this approach is very safe. But what about a 24*7 environment, if there is no "midnight" to do the replace.

Is it acceptable to simple replace a view if there could be some session reading it?  

I performed some simple test:  

1. start long select from a view
2. create or replace the view while the session is running
3. see what happen:)

 The reader session did "survived" (I guess with the cached version of the view).

But it is no prove!

Are there situation, where this approach can cause problems? Any experience with this topic on the list?  

Thanks  

Jaromir D.B. Nemec

http://www.db-nemec.com

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Received on Sun May 16 2004 - 10:47:00 CDT