Shulou(Shulou.com)06/01 Report--

Oracle 11g startup and shutdown

Startup nomount: open the database instance, read the parameter file, and start the necessary background processes, DBWR (database write process) LGWR (log write process) SMON (system monitoring process) PMON (process monitoring process) and CKPT (checkpoint process)

Startup mount: this status oracle finds and opens the control file based on the location of the control file in the parameter file, but does not open the data file

Startup open: opening data files

In fact, start the database normally and log in to oracle directly to execute sqlplus / as sysdba

Startup (automatically starts from nomount to open state)

NOMOUNT-- "MOUNT--" OPEN

Database shutdown step

Alter database close-- closes data files, log files, etc.

Alter database dismount-- closes the control file

Shutdown-- shuts down the database instance

The oracle database is usually shut down with the following command

Shutdown normal-- closes by default and does not allow new database links. Only when all current links exit, the database will be closed. If there are a large number of link users, it will take a long time to wait.

Shutdown immediate-- closes the database quickly and safely, recommended, forcibly disconnects all users, performs checkpoints to write dirty data to data files, interrupts transactions, and rolls back uncommitted transactions

This method is not recommended for shutdown abort--, which is similar to a forced power outage. After each restart, the instance is restored and the checkpoint operation is not performed. You can experiment with the virtual machine and check the log.

Shutdown transactional-- actually uses less, does not allow new links, and waits for all transactions to finish before shutting down the database

As shown in the figure above, you can see the process of database shutdown.

Closed-- "dismount--" shutdown

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