Oracle Database is ranked as the world’s most popular relational database, which provides many features to handle enormous amounts of data effectively. One such feature is Oracle Cluster, which groups similar data together based on specific criteria. Being an administrator, you should understand Clusters in Oracle to optimize the performance of your databases and improve the efficiency of its data storage.
This post will discuss Clusters in Oracle, its advantages, and disadvantages.
What is Cluster in Oracle?
Oracle provides an object named Cluster, for grouping related tables and storing them in the same database blocks. Clustering optimizes the database by reducing storage requirements and increasing its performance. All the tables that are grouped, consist of the same cluster key. The cluster key contains common columns in all tables of the cluster. The cluster key determines where the data should store when new data is entered in a table in a cluster.
The “CREATE CLUSTER” statement is utilized for creating a cluster. After the creation of Cluster, the user can store tables (maximum of 32 tables) in it. A user can specify a maximum of 16 columns as a cluster key.
The two types of clusters in Oracle are enlisted below:
- Indexed Clusters: It uses an index to sort the data in the cluster which makes data retrieval fast.
- Hash Clusters: It uses a hash function to define the location of the data within the cluster.
The user can choose any type of Cluster in Oracle, Indexed clusters are useful for tables with a few distinct values in the cluster key. Whereas, Hash clusters are good for tables with a huge number of distinct values in the cluster key or when data is accessed randomly.
Advantages of Cluster in Oracle
Let’s enlist a few advantages of Cluster in Oracle:
- It can read more data in a single I/O operation, which will improve query execution times.
- It can reduce cost and storage requirements by storing related data together.
- It allows administrators to perform maintenance tasks on related tables which optimizes the database.
- It simplifies the design of the database.
- It improves the data integrity that increases the data accuracy.
Disadvantages of Cluster in Oracle
Here, we will enlist some disadvantages of Cluster in Oracle:
- It makes database design and maintenance complex.
- It makes scalability difficult when the number of tables increases in a cluster.
You have learned about Cluster in Oracle. Being a database administrator, you can decide if you want to choose Cluster for your database or not.
Conclusion
Cluster in Oracle groups related tables and stores them in the same database blocks. It optimizes the database by reducing storage requirements and increasing its performance. There are two types of clusters, Indexed Clusters, and Hash Clusters. Indexed clusters are useful for tables with a few distinct values in the cluster key. Hash clusters are good for tables with a huge number of distinct values in the cluster key.
