Setting Up Connection Pooling on IBM i

Overview

If your log files are filling up with messages about connections to the IBM i (iSeries/AS/400), you can reduce both the number of messages and the number of connections by:

• Setting up connection pooling for your IBM i/iSeries/AS400 source connection

• Configuring the QZDASOINIT pool on the iSeries/AS400 side

Setting Up Connection Pooling

Connection pooling for your IBM i/iSeries/AS400 source connection is managed by the database connection tool. When connecting to the IBM i/iSeries/AS400, you typically use the Syniti Ritmo/i .NET data provider, which is included with Syniti Replicate.

Connection pooling allows up to 10 pooled connections that share an identical connection string to be reused without opening additional physical connections.

To set up connection pooling:

1. In the Management Center, expand the tree to display your source connection to the IBM i/iSeries/AS400.

2. Right-click the connection and select Connection Properties > entry connection.

3. Click the button next to the Connection value to open the Connection Properties dialog box for the data provider. This dialog box displays all the connection properties used by the data provider to connect to the IBM i/iSeries/AS400.

4. In the Connection String list, access the Pooling entry list and set its value to True.

5. Click OK to save your changes.

Configuring the QZDASOINIT Pool

QZDASOINIT jobs are the jobs on IBM i/iSeries/AS400 side serving the clients using DB2 via Optimized Database Server (Host Database Server). Every job represents one client connection (so you can have more than 1 job from every client box, depending on how many connections have been opened).

They usually run under the QUSRWRK subsystem. They're described as BATCHI jobs. BATCHI = BCI.BCI is Batch Immediate. These jobs use the Batch CPW capability of the machine, and not the interactive 5250 CPW capability.

QZDASOINIT are Pre-Started Jobs (PJ), which means that you can have one or more of them running in a pool even if no client is connected, waiting for clients to ask for connections. The number of Pre-Started Jobs is controlled by the subsystem description, so it is the QUSRWRK description that needs to be modified.

This configuration should be performed by an IBM i/iSeries/AS400 system administrator. It is important to ensure that enough database server jobs are available to service client requests. Otherwise, the system must start new QZDASOINIT jobs dynamically, which consumes system resources and slows down connection time.

1. To view the current settings for the QZDASOINIT prestart job, you can use the follwoing command:

   DSPSBSD SBSD(QUSRWRK)

2. Select Option 10 for Prestart job entries.

3. Select Option 5 on the QZDASOINIT program to display the details.

4. Run the following command to change parameters:

   CHGPJE SBSD(QUSRWRK) PGM(QSYS/QZDASOINIT)

Meaningful Parameters: