Re: Why service_names in init.ora?

Dina,

Services_names was mainly used for fail-over and load balancing service.

Cheers,

Reid Lai

Dino Hsu wrote:

> Dear all,
>
> We know that db_name, db_domain, instance_name and service_names are
> the most basic settings in init.ora. Obviously, instance_name is SID,
> unique on a machine, so host + SID (+ protocol) makes a tnsnames.ora
> (or connect string) entry; db_name + db_domain (= global database
> name) is unique on the network, so host + db_name.db_domain (or
> service_name in tnsnames.ora term) also makes a tnsnames.ora entry.
> However, I still don't know why service_names exists in addition to
> db_name and db_domain. Look at the doc:
>
> <<quote Oracle8i Reference begin>>
>
> SERVICE_NAMES
> Parameter type: String
>
> Syntax: SERVICE_NAMES =
>
> db_service_name [, db_service_name [,...] ]
>
> Parameter class: Static
>
> Default value: DB_NAME.DB_DOMAIN if defined
>
> Range of values: Any ASCII string or comma-separated list of string
> names
>
> SERVICE_NAMES specifies one or more names for the database service to
> which this instance connects. You can specify multiple services names
> in order to distinguish among different uses of the same database. For
> example:
>
> SERVICE_NAMES = sales.acme.com, widgetsales.acme.com
>
>
> You can also use service names to identify a single service that is
> available from two different databases through the use of replication.
>
> In an Oracle Parallel Server environment, you must set this parameter
> for every instance.
>
> If you do not qualify the names in this parameter with a domain,
> Oracle qualifies them with the value of the DB_DOMAIN parameter. If
> DB_DOMAIN is not specified, Oracle uses the domain of your local
> database as it currently exists in the data dictionary.
>
> See Also:
>
> Net8 Administrator's Guide for more information on this parameter and
> its settings.
>
> "DB_DOMAIN".
>
> <<quote Oracle8i Reference end>>
>
> service_names is pretty much the same thing as db_name + db_domain
> except that service_names is plural, which means one instance or one
> database has one or more service_names? What are the 'different uses
> of the same database'? Anyone knows this? Thanks in advance.
>
> Dino
Received on Mon Sep 03 2001 - 23:20:30 CDT