Questions about shared server

Hello,
In our application we used dedicated server in Oracle 8.1.7, and this was done by adding a comment sign on this line in init.ora # mts_dispatchers = "(protocol=TCP)"

A tuning expert recommended NOT using multi-threaded server was and it worked fine.

Having upgraded to Oracle 9.2.0.4 for Linux there are some performance problems. Oracle doc says:
"In general, it is better to be connected through a dispatcher and use
a shared server process. This is illustrated in Figure 5-2, "Oracle Shared Server Processes". A shared server process can be more efficient because it keeps the number of processes required for the running instance low."

Question 1: Is this true - is it really better to use a shared server than dedicated or should we try to avoid using shared server (as in 8.1.7) when experiencing performance problems?

I have tried to switch the shared server off by following this guideline from Oracle:

"After starting an instance, you can change the minimum number of
shared server processes by using the SQL statement ALTER SYSTEM. Oracle will eventually terminate servers that are idle when there are more shared servers than the minimum limit you specify. If you set SHARED_SERVERS to 0, Oracle terminates all current servers when they become idle and does not start any new servers until you increase SHARED_SERVERS. Thus, setting SHARED_SERVERS to 0 may be used to effectively disable shared server."

However - when take a I look in v$session I can see sessions where Server=SHARED..

When taking a look in v$parameter I see this: shared_servers 0
max_shared_servers 20

dispatchers      (PROTOCOL=TCP)
max_dispatchers     5

Did I not succeed when I tried to stop using shared server..?

Thanks for advice on this,
Randi W Received on Mon Apr 03 2006 - 05:45:34 CDT