An Oracle instance is a combination of______.

Question

Options

• Adatabase files and parameter file (initialization parameter file or server parameter file)
• BSystem Global Area (SGA) and background processes
• Ca listener process, server processes, and background processes
• DSystem Global Area (SGA), server processes, and background processes
• Edatabase files, System Global Area (SGA), and background processes

• A
  6% (2)
• B
  78% (28)
• C
  3% (1)
• D
  14% (5)

Explanation

https://docs.oracle.com/database/121/CNCPT/startup.htm#CNCPT601 Introduction to the Oracle Database Instance A database instance is a set of memory structures that manage database files. A database is a set of physical files on disk created by the CREATE DATABASE statement. The instance manages its associated data and serves the users of the database. Every running Oracle database is associated with at least one Oracle database instance. Because an instance exists in memory and a database exists on disk, an instance can exist without a database and a database can exist without an instance. Database Instance Structure When an instance is started, Oracle Database allocates a memory area called the system global area (SGA) and starts one or more background processes. The SGA serves various purposes, including the following: - Maintaining internal data structures that many processes and threads access concurrently - Caching data blocks read from disk - Buffering redo data before writing it to the online redo log files - Storing SQL execution plans Oracle processes running on a single computer share the SGA. The way in which Oracle processes associate with the SGA varies according to operating system. A database instance includes background processes. Server processes, and the process memory allocated in these processes, also exist in the instance. The instance continues to function when server processes terminate.

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