Liberty servlet with JDBC and JCICS access

This workload is a pure Java application, based on the CICS-supplied JDBC sample application.

For more information about the sample JDBC servlet application, see Java samples: Servlet examples.

The sample application is composed of a Java servlet, which accesses an SQL database by using the Java JDBC API. The values that are retrieved from the database are then rendered as an HTML page and sent to the client as the response. For this workload, the sample application was expanded to also access a VSAM file by using the JCICS interface. The VSAM file contains a copy of the data that is held in the sample database.

The supplied sample application uses the CICSDB2DynamicSQLExample.getData(String) method to read 42 rows from the sample Db2® table EMP. This method was modified to read also 42 records from a VSAM file by using JCICS KeyedFileBrowse.next() calls and to display the data as extra entries in the HTML table that is returned to the client.

The application is deployed into a Liberty environment inside a CICS JVM server. Simulated browser requests are made to the HTTP port that is specified in the server.xml configuration file. Figure 1 shows an overview of the application topology.

Figure 1. Topology of JDBC and VSAM servlet workload
Flow as described in the surrounding text
The Liberty server configuration file server.xml was automatically generated by specifying the following options in the JVM profile file for the JVM server:
  • -Dcom.ibm.cics.jvmserver.wlp.autoconfigure=true
  • -Dcom.ibm.cics.jvmserver.wlp.server.host=hostname
  • -Dcom.ibm.cics.jvmserver.wlp.server.name=serverName
  • -Dcom.ibm.cics.jvmserver.wlp.server.http.port=httpPort
The following entry was also added to the JVM profile configuration file to optimize retrieval of static resources from the web application: 
-Dcom.ibm.cics.jvmserver.wlp.optimize.static.resources=true

By using IBM Workload Simulator for z/OS, 200 HTTP clients were simulated to provide a controlled rate of transactions in the CICS region under test. The workload measured overall central processor usage and zIIP usage of the address space.