Re: What are the GV$ and X$ Objects ?

From: Mark D Powell <Mark.Powell_at_eds.com>
Date: Sat, 25 Apr 2009 06:53:59 -0700 (PDT)
Message-ID: <a86aea09-2df9-4595-a662-cdc78a65c868_at_x29g2000prf.googlegroups.com>

On Apr 25, 12:17 am, Jia Lu <Roka..._at_gmail.com> wrote:
> Hi all
>
> V$ objects are dynamic performance views.
> but what are the GV$ and X$ Objects ?
>
> Thanks

The gv$ views were added to provide RAC versions of the v$ views. The v$ views are now based on the underlying gv$ views. Where the v$ views shows information for the current instance of Oracle the same query on the gv$ version of the view returns the same information for all running instances of the database. In the case of a non-RAC install the results will be the same (ignoring instance column)

The x$ views are mappings to control structures: records, linked lists, arrays, etc ... that exist in the Oracle SGA. In other words the x$ views are the Oracle internal memory structures.

The v$ views are documented in the Oracle version# Reference manual.

HTH -- Mark D Powell -- Received on Sat Apr 25 2009 - 08:53:59 CDT