IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

Chapter 21. IMS Remote Database Services 461

Figure 21-56 Result page for the failure with the exception (DFSIVP37 PSB is stopped status)

Also, you will see the following messages shown in Example 21-34 on the console log of

WebSphere Application Server for distributed platforms.

Example 21-34 Console log of WebSphere Application Server for distributed platforms (with exception)

[6/27/05 18:02:13:504 PDT] 0000003f SystemOut O IMS RDS Servlet : Success Start UserTransaction

[6/27/05 18:02:13:504 PDT] 0000003f SystemOut O IMS RDS Servlet : Success Get Connection

[6/27/05 18:02:14:415 PDT] 0000003f SystemOut O IMS RDS Servlet : Success Rollback UserTransacton

[6/27/05 18:02:14:505 PDT] 0000003f SystemOut O IMS RDS Servlet : Caught exception in main section is:

java.sql.SQLException: javax.resource.spi.EISSystemException: java.lang.RuntimeException: AIB return code

(AIBRETRN): 108 AIB reason code (AIBREASN): 30c

Function: APSB

Status Code Hex: 4040

AIB Return Code Hex (AIBRETRN): 108

AIB Reason Code Hex (AIBREASN): 30c

AIB Error Code Extension Decimal (AIBERRXT): -993598775

[6/27/05 18:02:14:505 PDT] 0000003f SystemOut O IMS RDS Servlet : Success Dispatch Result

[6/27/05 18:02:14:515 PDT] 0000003f SystemOut O IMS RDS Servlet : End

This information represents the following situation:

 The servlet received java.sql.SQLException when it executed the SQL query, and then it

roll backed the user transaction.

 The exception information delivered from the IMS Java EJB contains the AIB return code

X'108' and the AIB reason code X'30C', which means: “The program attempted to allocate

a PSB that is marked permanently bad. IMS cannot allocate the PSB.”

21.5.8 Problem determination for Remote Database Services

The Remote Database Services consists of a lot of components and applications to deliver

your SQL request to the IMS ODBA interface. This means that whenever your Web

application gets an exception, all of the components will be candidates for your problem

determination. Some of the information that can be used for this purpose includes:

 java.sql.SQLException information that you receive

 WebSphere Application Server for distributed platforms console logs

 IMS distributed JDBC resource adapter traces

 WebSphere Application Server for z/OS console logs

 IMS JDBC resource adapter traces

 Joblogs of WebSphere Application Server for z/OS servant regions and control region

462 IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

 IMS system messages

 IMS logs and traces, dumps (usually in case of a defect)

In this section, we introduce some techniques to determine a problem concerning the Remote

Database Services. For the basic concepts of problem determination for the ODBA

environment, see 19.6.1, “Finding the problem” on page 375.

Tracing DL/I calls with image capture

The SQL requests from your Web application will change into DL/I calls in the IMS Java

engine on the WebSphere Application Server for z/OS side. Therefore, if you have a

performance problem with executing a SQL, or receive an unexpected result for the query

condition, it is a good idea to evaluate how your SQL is described in the DL/I call format

intently. For this purpose, you can use the tracing facility for DL/I calls with image captures by

using the IMS command.

To take a DL/I call image capture (for example, for the PSB DFSIVP37), use the following

sequence of events for tracing:

1. Turn on trace with the following command:

/TRACE SET ON PSB DFSIVP37 COMP

2. Run the Web application.

3. Turn off trace with the following command:

/TRACE SET OFF PSB DFSIVP37

4. Switch the online log data sets (OLDSs). This also causes the contents to be archived to

the secondary log data sets (SLDSs) with the following command:

/SWITCH OLDS

5. Execute the print utility DFSERA10, specifying the latest SLDS as input in SYSUT1 DD.

The DFSERA10 input control statements to retrieve the information from the log look

similar to the following statements (in a format that can be used as input to DFSDDLT0):

OPTION PRINT OFFSET=5,VALUE=5F,COND=M

OPTION PRINT EXITR=DFSERA50,OFFSET=25,FLDTYP=C

VALUE=DFSIVP37,FLDLEN=8,DDNAME=OUTDDN,COND=E

For example, we executed the SQL statement shown in Example 21-35 against the PERSON

table through the metadata DFSIVP37DatabaseView with the DL/I call image capture trace.

Example 21-35 SQL example

SELECT * FROM PhoneBook.Person

After formatting the IMS log that contains trace data (X'5F' log), we see the trace result shown

in Example 21-36.

Example 21-36 DL/I call image capture result

U DATE=2005/180 TIME=15.04.09 DFSIVP37

S 1 1 1 1 1

S 1 1 1 1 1 000011

L GHU A1111111

E DATA LAST6 FIRST6 8-111-6666D06/R06

E 01 A1111111 0010LAST6

L GHN A1111111

E DATA LAST1 FIRST1 8-111-1111D01/R01

E 01 A1111111 0010LAST1

L GHN A1111111