How to query the current number of connections in Oracle (two methods)

The number of Oracle database connections refers to the number of clients connected to the Oracle database at the current moment. For administrators who maintain the database, it is very helpful to keep track of the number of connections at all times. This article will introduce how to query the current number of connections in Oracle database.

In Oracle database, there are many ways to query the current number of connections. Two methods will be introduced below.

Method 1: Use the V$SESSION view

In the Oracle database, V$SESSION is one of the system views used to display all current connection information.

1. In the SQL command line interface, enter the following command to query the current number of connections:

SELECT COUNT(*) FROM V$SESSION;

2. After running the SQL statement, you can get the results, for example:

  COUNT(*)
----------
         7

Among them, COUNT(*) represents the number of current connections. In the above example, the current number of connections is 7.

Method 2: Use the query of the current session

In the Oracle database, use SELECT SYS_CONTEXT ('USERENV', 'SID') to query the current session ID. We can use this method to query the current number of connections.

1. First, query the current session ID:

SELECT SYS_CONTEXT ('USERENV', 'SID') "SESSION ID" FROM DUAL;

2. Then, query the number corresponding to the session ID:

SELECT COUNT(*) FROM V$SESSION WHERE AUDSID = SYS_CONTEXT('USERENV', 'SESSIONID');

Run the above two SQL statements to get the current number of connections.

No matter which method is used, the query results will not deliberately change temporarily. Because in the SQL command line interface, query statements do not actually involve a large number of operations interacting with the database, therefore, the query results are certain within a period of time.

Summary

The above are two simple ways to query the number of Oracle connections. Through the above SQL statement, you can know the number of connections to the database at any time, which is very helpful for monitoring and maintaining the database.

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