How to check the maximum number of allowed connections to an Oracle database?

sql oracle
Niklas Gustavsson picture Niklas Gustavsson · Oct 2, 2008 · Viewed 468.6k times · Source

What's the best way, using SQL, to check the maximum number of connections that is allowed for an Oracle database? In the end, I would like to show the current number of sessions and the total number allowed, e.g. "Currently, 23 out of 80 connections are used".

Answer

Justin Cave picture Justin Cave · Oct 2, 2008

There are a few different limits that might come in to play in determining the number of connections an Oracle database supports. The simplest approach would be to use the SESSIONS parameter and V$SESSION, i.e.

The number of sessions the database was configured to allow

SELECT name, value 
  FROM v$parameter
 WHERE name = 'sessions'

The number of sessions currently active

SELECT COUNT(*)
  FROM v$session

As I said, though, there are other potential limits both at the database level and at the operating system level and depending on whether shared server has been configured. If shared server is ignored, you may well hit the limit of the PROCESSES parameter before you hit the limit of the SESSIONS parameter. And you may hit operating system limits because each session requires a certain amount of RAM.

Related questions

Get list of all tables in Oracle?

How do I query an Oracle database to display the names of all tables in it?

Read More
How do I limit the number of rows returned by an Oracle query after ordering?

Is there a way to make an Oracle query behave like it contains a MySQL limit clause? In MySQL, I can do this: select * from sometable order by name limit 20,10 to get the 21st to the 30th rows (skip the …

Read More
Oracle SQL: Update a table with data from another table

Table 1: id name desc ----------------------- 1 a abc 2 b def 3 c adf Table 2: id name desc ----------------------- 1 x 123 2 y 345 In oracle SQL, how do I run an sql update query that can update Table 1 with Table 2's name and desc using …

Read More