Sunday, 2 February 2025

What are the main components of the SGA in Oracle Database 19c?

The System Global Area (SGA) in Oracle Database 19c is a crucial memory area that stores data and control information for a single Oracle Database instance. It's shared by all server and background processes. Here are the main components:

Database Buffer Cache: This is where data blocks read from data files are stored. It helps speed up data access by keeping frequently used data in memory.   

Redo Log Buffer: This circular buffer stores redo entries, which record changes made to the database. These entries are essential for database recovery.   

Shared Pool: This pool caches parsed SQL statements, PL/SQL code, and data dictionary information. It improves performance by reusing these components.   

Large Pool: This optional pool is used for memory allocations larger than those suitable for the shared pool. It can be used for things like shared server user global areas (UGAs) and parallel execution message buffers.   

Java Pool: This pool is used for Java objects and code when using Java in the database.   

Streams Pool: This pool is used for Oracle Streams, a feature for data replication and integration.   

In-Memory Area: This optional area allows storing tables and partitions in memory in a columnar format, which significantly speeds up analytical queries.   

Memoptimize Pool: This optional component provides high performance and scalability for key-based queries.   

These components work together to ensure efficient and fast database operations.

If you want to know more about these components, you can find details explanation provided here.


I hope this helps !!

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