|Oracle9i SQL Reference
Release 2 (9.2)
Part Number A96540-01
Common SQL DDL Clauses , 2 of 9
allocate_extent_clause clause to explicitly allocate a new extent for a database object.
Explicitly allocating an extent with this clause does not change the values of the
PCTINCREASE storage parameters, so does not affect the size of the next extent to be allocated implicitly by Oracle.
You can allocate an extent in the following SQL statements:
CLUSTER(see ALTER CLUSTER)
INDEX: to allocate an extent to the index, an index partition, or an index subpartition (see ALTER INDEX)
VIEW: to allocate an extent to the materialized view, one of its partitions or subpartitions, or the overflow segment of an index-organized materialized view (see ALTER MATERIALIZED VIEW)
LOG(see ALTER MATERIALIZED VIEW LOG)
TABLE: to allocate an extent to the table, a table partition, a table subpartition, the mapping table of an index-organized table, the overflow segment of an index-organized table, or a LOB storage segment (see ALTER TABLE)
This section describes the parameters of the
allocate_extent_clause. For additional information, refer to the SQL statement in which you set or reset these parameters for a particular database object.
You cannot specify the
Specify the size of the extent in bytes. Use
M to specify the extent size in kilobytes or megabytes.
For a table, index, materialized view, or materialized view log, if you omit
SIZE, then Oracle determines the size based on the values of the storage parameters of the object. However, for a cluster, Oracle does not evaluate the cluster's storage parameters, so you must specify
SIZE if you do not want Oracle to use a default value.
Specify one of the datafiles in the tablespace of the table, cluster, index, materialized view, or materialized view log to contain the new extent. If you omit
DATAFILE, then Oracle chooses the datafile.
Use this parameter only if you are using Oracle with Real Application Clusters.
integer makes the new extent available to the freelist group associated with the specified instance. If the instance number exceeds the maximum number of freelist groups, then Oracle divides the specified number by the maximum number and uses the remainder to identify the freelist group to be used. An instance is identified by the value of its initialization parameter
If you omit this parameter, then the space is allocated to the table, cluster, index, materialized view, or materialized view log but is not drawn from any particular freelist group. Instead, Oracle uses the master freelist and allocates space as needed.
If you are using automatic segment-space management, then the
Oracle9i Real Application Clusters Administration for more information on setting the