Database nomount status-V $ process view

I. Database nomount status

In step 1 of startup, Oracle first looks for the parameter file (pfile/spfile ). Then, based on the settings in the parameter (such as memory allocation), create an instance, allocate memory, and start the background process. You can view the entire process.Altert(Warning) log(How to query the path, use sqlplus, show parameter backgound_dump_dest ).Nomount is the process of starting a database instance.

Sqlplus/nolog

Conn/As sysdba

Shutdown immediate

Startup nomount;

1. V $ process view

A) The spid column in the query output of V $ process represents the process number on the operating system. The spid can be used to associate the process from the operating system to the database:

B) You can use PS-Ef | grep ora _ to view processes in Linux _

C) operating system process exception (high CPU usage)

Then, by associating the PID on the operating system with the spid in the V $ process view, you can track and diagnose the processes on the OS in the database.

D) The V $ process view contains information about active processes in the current database.

1) latch in V $ Process

The latchwait column indicates the latch information that the process is currently waiting for. The latchspin record that the process is competing for latch through spin. latch can be used to understand the lock mechanism inside the database, mainly to control the concurrency of memory. oracle processes compete for latch through spin (spin.

2) associate with V $ session through ADDR

The paddr recorded in the V $ session view is V $ process. ADDR, which is associated with the V $ session.