<p>My PHP/MS Sql Server 2005/win 2003  Application occasionally becomes very unresponsive, the memory/cpu usage does not spike. If i try to open any new connection from sql management studio, then the it just hangs at the open connection dialog box. 
how to deterime the total number of active connections ms sql server 2005</p>

This shows the number of connections per each DB:
```
```
SELECT 
    DB_NAME(dbid) as DBName, 
    COUNT(dbid) as NumberOfConnections,
    loginame as LoginName
FROM
    sys.sysprocesses
WHERE 
    dbid > 0
GROUP BY 
    dbid, loginame
```
```
And this gives the total:
```
```
SELECT 
    COUNT(dbid) as TotalConnections
FROM
    sys.sysprocesses
WHERE 
    dbid > 0
```
```
If you need more detail, run:
```
```
sp_who2 'Active'
```
```
Note:
The SQL Server account used needs the 'sysadmin' role (otherwise it will just show a single row and a count of 1 as the result)