How do you determine the optimal SGA value for a given workload?

How to configure System Global Area (SGA) for your Oracle database? How do you know how much shared memory you need to provide to your database? 

Determining the optimal SGA size for a given workload is a crucial aspect of Oracle database performance tuning. It involves a combination of analysis, testing, and iterative adjustments. Here's a breakdown of the process:

Detailed Explanation to SGA Components in Oracle Database

What is the role & impact of different SGA components? 

The System Global Area (SGA) is a crucial memory area in Oracle databases, shared by all server processes and background processes.  It holds data and control information for a single database instance, significantly impacting performance.  Efficient management of the SGA is essential for optimal database operation. Here's a more detailed look at its components:

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:

Components of Oracle DB BUFFER CACHE

What are the components of DB BUFFER CACHE?

Below mentioned are the components of db buffer cache,

• Default pool (where blocks are normally buffered)
• Big table cache (optional part of the default pool; uses a temperature based algorithm instead of the LRU based one)
• Keep pool - data buffers for frequently running queries
• Recycle pool - data buffers for least running queries
• Non-default buffer pools (used for non-standard block sizes of 2, 4, 16 or 32 KB, when you have different tablespaces with different db block sizing)
• Database Smart Flash Cache (used in flash cache)
• Least Recently Used list (LRU)
• Checkpoint queue
• Flash Buffer Area

Cache Hit vs Cache Miss in Oracle Database

 Difference between Cache Hit and Cache Miss

Cache Hit: When running a SELECT statement within Oracle database, if the relevant data is already found in the db buffer cache, that signifies its a Cache Hit. 

Cache Miss: When any transaction is not able to find data in the db buffer cache and it has to go to datafile to fetch that data, it means cache miss. Which means it would take more time to process that transaction.

The more Cache hit ratio you have, the better performance you have within your database. It is always beneficial to keep data buffers available for frequently running queries within db buffer cache and hence database memory components should be tuned accordingly.

Overview to Oracle Instance Memory Structures - SGA Explained

What is SGA or System Global Area in Oracle Database? A complete explanation guide to Oracle Memory Structures? Various components of SGA Explained in detail.

SGA also known as Shared Global Area is a very important part of Oracle Memory Architecture. As I have mentioned in one of my previous posts regarding the Explanation of Oracle Database Server that SGA is the part of Oracle Instance which includes some memory components and some background process which work together to keep the Oracle Database Server running.