Oracle Database Memory Architecture
The Oracle Database Memory Architecture refers to the organization and management of memory resources within an Oracle database instance. It comprises various memory structures and components that collectively handle data storage, caching, and processing. These memory structures are designed to optimize performance, scalability, and reliability of the database system.
The primary components of the Oracle Database Memory Architecture are:
- System Global Area (SGA)
The SGA is a shared memory region that is allocated when the Oracle database instance starts. It contains data and control structures that are shared among all users and processes connected to the instance.
SGA Components
The System Global Area (SGA) consists of several key components that play crucial roles in the operation of an Oracle database. Here are the primary components of the SGA
- Program Global Area (PGA)
The PGA is a memory region allocated for each individual database session or server process. It stores private session-specific data and runtime memory structures. Each user session or process has its own PGA, ensuring isolation and preventing interference between sessions.
The Program Global Area (PGA) is an essential memory structure in Oracle databases, specifically allocated for a dedicated server session. It is subdivided into various areas, each serving distinct purposes. Here’s an overview of the key contents of the PGA
- User Global Area (UGA)
The User Global Area (UGA) is a memory region within the Program Global Area (PGA) that stores session-specific user data and information. It primarily contains data structures related to the execution of SQL statements and processing of user transactions
