Several new data dictionary views exist to help you manage ASM. These data dictionary views are available both when connected to the ASM instance as well as to any Oracle Database 10g database. Each view is slightly different in its presentation depending on whether the instance you are looking at is an ASM instance or a database instance (and some views are only used in the ASM instance). Let's quickly look at these views.

V$ASM_ALIAS

When you are connected to an ASM instance, the V$ASM_ALIAS view displays a single row for every alias present in every disk group mounted by the ASM instance. This view is not used when connected to a normal database instance (no rows will be displayed).

V$ASM_CLIENT

When you are connected to an ASM instance, the V$ASM_CLIENT view displays a single row for every database instance using a disk group managed by the ASM instance. When you are connected to a normal database instance and the database has open ASM files, the V$ASM_CLIENT view displays a single row for the ASM instance.

V$ASM_DISK

When you are connected to an ASM instance, the V$ASM_DISK view displays a single row for every disk discovered by the ASM instance, including disks that are not part of any disk group. When you are connected to a normal database instance, the V$ASM_DISK view only displays rows for disks in disk groups in use by the database instance.

V$ASM_DISKGROUP

When you are connected to an ASM instance, the V$ASM_DISKGROUP view displays a single row for each disk group discovered by the ASM instance. When you are connected to a database instance, the V$ASM_DISKGROUP view displays a single row for every ASM disk group mounted by the local ASM instance.

V$ASM_FILE

When you are connected to an ASM instance, the V$ASM_FILE view displays a single row for every ASM file in every disk group mounted by the ASM instance. This view is not used when connected to a normal database instance (no rows will be displayed).

V$ASM_OPERATION

When you are connected to an ASM instance, the V$ASM_OPERATION view displays a single row for every active ASM long-running operation executing in the ASM instance. This view is not used when connected to a normal database instance (no rows will be displayed).

V$ASM_TEMPLATE

When you are connected to an ASM instance, the V$ASM_TEMPLATE view displays a single row for every template present in every disk group mounted by the ASM instance. When you are connected to a database instance, the V$ASM_TEMPLATE view displays a single row for every ASM disk group mounted by the local ASM instance.

This is just a quick introduction to the power of ASM. A small book probably could be written on just this new feature alone. Still, I hope I have gotten you interested in it!

This chapter is from Oracle Database 10g New Features, by Robert Freeman (McGraw-Hill/Osborne, 2004, ISBN: 0072229470). Check it out at your favorite bookstore today. Buy this book now.