Hi, everyone, I have a problem in imagining the way DB2 UDB handles MTS (Multi Threaded Server) architecture. I know that there's several parameters that would determine this handling process, such as :
- maxappls
- numdb
- maxcagents

Besides those parameters, is there any other parameter that has to be set to be able to support MTS architecture ? Is num_ioservers included ??

What DB2 version and operating system are you using?

I'm currently using Linux Redhat 4 and DB2 UDB 8.1

DB2 has switched to a threaded architecture in version 9.5. That just means that connections don't require separate processes in the operating system. DB2 runs as a multi-tasking application in version 8.

With regard to maxagents, that defines how many agents can be connected to DB2 at one time (unless you are using DB2 connection pooling with ESE). Each application connection is one agent, unless that connection is doing some parallel operation such as parallel query (intra-partition parallelism).

The num_ioservers tells DB2 how many i/o server processes to run at one time when interfacing with the disk subsystem. This is usually set based on the number of CPU's you have and/or the number of containers per tablespace that you have.

In version 9.1 and especially in V9.5, the new automatic configuraton will let DB2 manage these settings dynamically for you, or you can set them manually.

"Multithreaded server" (MTS) is an Oracle term; it is somewhat similar to what is called a connection concentrator in DB2.

To enable the connection concentrator you set MAX_COORDAGENTS to be larger than MAX_CONNECTIONS. MAXAGENTS and NUM_POOLAGENTS should also be set accordingly.

NUMDB has nothing to do with the connection concentrator, neither has NUM_IOSERVERS.

The connection concentrator is only available on DB2 Enterprise (aka ESE).

If connection concentrator only available at ESE, what would happen if we change the max_connections and maxagents value at the other edition ?? Oh yeah, btw, does anyone know how to check whether one's DB2 version is Express or Personal or Enterprise Edition ???

Run this on the server:
db2licm -l