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Oracle® Database Reference 10g Release 2 (10.2) Part Number B14237-02 |
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# INSTANCE_NUMBER

Property | Description
--- | ---
Parameter type | Integer
Default value | Lowest available number; derived from instance start up order and `INSTANCE_NUMBER` value of other instances. If not configured for Real Application Clusters, then `0`.
Modifiable | No
Range of values | 1 to maximum number of instances specified when the database was created
Basic | Yes
Real Application Clusters | You must set this parameter for every instance, and all instances must have different values.

`INSTANCE_NUMBER` is a Real Application Clusters parameter that can be specified in parallel mode or exclusive mode. It specifies a unique number that maps the instance to one free list group for each database object created with storage parameter `FREELIST GROUPS`.

The `INSTANCE` parameter of the `ALTER TABLE ... ALLOCATE EXTENT` statement assigns an extent to a particular free list group. If you set `INSTANCE_NUMBER` to the value specified for the `INSTANCE` parameter, the instance uses that extent for inserts and for updates that expand rows.

The practical maximum value of this parameter is the maximum number of instances specified in the `CREATE DATABASE` statement. The absolute maximum is operating system-dependent.

See Also: Oracle Database Oracle Clusterware and Oracle Real Application Clusters Administration and Deployment Guide for more information