Which process starts first when an instance is started?

The first process that will be started when we start instance is PSP process. This is called PROCESS SPAWNER.

Which file will be required to mount a database that has been started as startup Nomount?

The instance carries the following steps to mount a database: First, get the name of the database control files specified in the CONTROL_FILE initialization parameter. Second, open the control files. Third, find the name of data files and the online redo log files.

What happens during the startup of an Oracle database?

The Startup (nomount) Stage During the nomount stage, Oracle first opens and reads the initialization parameter file (init. Together, we call these processes and the associated allocated memory the Oracle instance. Once the instance has started successfully, the database is considered to be in the nomount stage.

What starts the instance and allows users to access the database?

Only the database administrator can start up an instance and open the database. If a database is open, then the database administrator can shut down the database so that it is closed. When a database is closed, users cannot access the information that it contains.

What is instance database?

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.

What is DB instance Oracle?

An Oracle instance (also known as a database instance) contains the set of Oracle Database background processes that operate on the stored data and the shared allocated memory that those processes use to do their work.

What is the meaning of database already mounted?

“Database already mounted” means the database’s control file is already opened within a running ORACLE instance.

Why is it so long to shut down immediate?

Shutdown immediate can take long time to complete (appear to be hung) because of three reasons: 1. Uncommitted transactions are being rolled back. 2.

What is a Oracle database instance?

What is database instance in SQL Server?

An instance of the Database Engine is a copy of the sqlservr.exe executable that runs as an operating system service. Each instance manages several system databases and one or more user databases. Each computer can run multiple instances of the Database Engine.

What is database instance?

What is a SQL database instance?

What happens when you start an Oracle instance?

After starting an instance, Oracle associates the instance with the specified database. This is a mounted database. The database is then ready to be opened, which makes it accessible to authorized users. Multiple instances can run concurrently on the same computer, each accessing its own physical database.

How does Oracle database perform instance recovery automatically?

Oracle Database performs instance recovery automatically in the following situations: 1 The database opens for the first time after the failure of a single-instance database or all instances of an Oracle RAC… 2 Some but not all instances of an Oracle RAC database fail. Instance recovery is performed automatically by a surviving… More

What are background processes in a database instance?

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.

What is the difference between a single-instance and multiple instances of database?

This chapter discusses a single-instance database configuration unless otherwise noted. Multiple instances can run concurrently on the same computer, each accessing its own database. For example, a computer can host two distinct databases: prod1 and prod2. One database instance manages prod1, while a separate instance manages prod2.