Clusters Editor (Oracle)

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The Clusters Editor lets you manage cluster column and table details, view and modify storage and space parameters, and manage performance settings for a cluster.

To edit a cluster

  1. Open an editor on the cluster. For details, see Opening an Object Editor.
  2. Use the following table as a guide to understanding and modifying the settings on the tabs of this editor:
Tab Settings and tasks


Use the controls in the General Properties group to specify a hash or index Cluster Type and to specify a Key Size for the cluster. If you specify a hash cluster type, use the controls in the Hash Specifications group to specify the number of hash keys and to specify use of either the default hash function or a specified expression used as the hash function.


Lets you manage storage for a cluster:

Data Block Storage

Each transaction that updates a data block requires a transaction entry. Percent Free - minimum percentage of free space in a block Percent Used - minimum percentage of used space in a block. Initial transactions - The initial parameter ensures that a minimum number of concurrent transactions can update a data block, avoiding the overhead of allocating a transaction entry dynamically. Maximum transactions - The maximum parameter limits concurrency on a data block.


The unit of space allocated to an object whenever the object needs more space. Initial Extent - The initial space extent (in bytes) allocated to the object. Next Extent - The next extent (in bytes) that the object will attempt to allocate when more space for the object is required. Minimum Extents - The appropriate minimum extents value for the object. Maximum Extents - The appropriate maximum extents value for the object. Percent Increase - Magnifies how an object grows and, can materially affect available free space in a tablespace. Select a value in the corresponding box.

Optionally, you can modify the Percent Free, Percent Used, or Max Transactions values.


Lets you modify the following performance settings:

Parallel Query Option group

Lets you specify Degrees and Instances settings for processing queries using many query server processes running against multiple CPUs, which provides substantial performance gains such as reduction of the query completion time.

Cache group

The Cache setting keeps the blocks in memory by placing it at the most recently used end. This option is useful for small lookup tables.


Lets you view the following usage and the space distribution details:

Space Utilization group

Displays the percent of space reserved for future updates.

FreeLists group

Displays the allocation of data blocks when concurrent processes are issued against the cluster. Identifying multiple freelists can reduce contention for freelists when concurrent inserts take place and potentially improve the performance of the cluster.

Extents group

The unit of space allocated to an object whenever the object needs more space.


Lets you view details for each cluster column. Details for each column include the key column in the cluster, the clustered table name, and the key column in the table.


For details on using this tab, see Viewing the SQL/DDL for an Object.

3. When finished, you can submit your changes. For details, see Previewing and Submitting Object Editor Changes.