What are the stages of Oracle database startup?

Oracle database startup is divided into 7 stages: 1. Initialization; 2. Instance recovery; 3. Archive log recovery; 4. Crash recovery; 5. Object opening; 6. Server preparation; 7. Server startup. The process involves loading library files, configuring parameters, restoring the database instance, applying archive logs, updating data files and objects, and finally starting the database service to accept queries.

Oracle database startup phase

Oracle database startup is a multi-stage process involving the following main stages:

1. Initialization phase

• Load library files and configuration parameters
• Initialize shared memory
• Create background process

2. Instance recovery phase

• Recover the database instance from the data file and control file
• Verify the consistency of the data file and control file
• Redo uncommitted transactions

3. Archive log recovery phase

• If the archive log is available, apply the archive log to Implement data recovery
• Rebuild committed transactions based on redo log entries
• Update data files to reflect the recovered changes

4. Crash recovery phase

• Crash recovery if the database is shut down under abnormal circumstances
• Analyze redo logs and recover uncommitted transactions
• Update data based on redo log entries File

5. Object opening phase

• Open objects in the database, such as tables, views and programs
• Use Oracle Data dictionary verifies the consistency of the object

6. Server preparation phase

• Create a listener process to listen for client connections
• Configure network settings and start the database service

7. Server startup phase

• Listener accepts client connection
• Creation Server process to handle client requests
• The database instance is fully started and can accept queries

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