Re: v$ views and control files

From: K Gopalakrishnan <kaygopal_at_gmail.com>
Date: 10 May 2005 09:54:03 -0700
Message-ID: <1115744043.546945.318060@o13g2000cwo.googlegroups.com>

John:

I think you misunderstood the logic. X$tables (okay.. they are not) are not tables. They are views. To be more accurate, X$s are just memory constructs. They do not store the data anywhere in the dictionary. They just represent the runtime memory structure values in a table format, and that can be acessed via standard SQL.

(May be some one else can give a better definition!).

So, now to answer your question, when the database is mounted, the instance will have memory structures. So what you see in X$ at that time is the current snapshot(!) or current values of the memory structures. X$ does not support read consistency, dirty reads are also possible.

Best Regards,
K Gopalakrishnan
Co-Author: Oracle Wait Interface, Oracle Press 2004 http://www.amazon.com/exec/obidos/tg/detail/-/007222729X/ Received on Tue May 10 2005 - 11:54:03 CDT