Disk I/O is reduced & access time improves for joins of clustered tables - Oracle Clusters

Q.  Disk I/O is reduced and access time improves for joins of clustered tables.
- Published on 29 Jul 15

a. True
b. False

ANSWER: True
 

    Discussion

  • Nirja Shah   -Posted on 02 Sep 15
    - A cluster provides an optional method of storing table data.

    - A cluster is made up of a group of tables that share the same data blocks.

    - The tables are grouped together because they share common columns and are often used together.

    - Because clusters store related rows of different tables together in the same data blocks, properly used clusters offer two primary benefits:

    1. Disk I/O is reduced and access time improves for joins of clustered tables.

    2. The cluster key is the column, or group of columns, that the clustered tables have in common.
    - You specify the columns of the cluster key when creating the cluster.
    - You subsequently specify the same columns when creating every table added to the cluster.
    - Each cluster key value is stored only once each in the cluster and the cluster index, no matter how many rows of different tables contain the value.

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