| Oracle® Transparent Gateway for DRDA Installation and User’s Guide 10g Release 1 (10.1) for UNIX Part No. B12009-01 |
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| Oracle® Transparent Gateway for DRDA Installation and User’s Guide 10g Release 1 (10.1) for UNIX Part No. B12009-01 |
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This chapter provides information about error messages and error codes. This data is specific to this release of the Oracle Transparent Gateway for DRDA, including the following sections:
The gateway architecture involves a number of separate components. Any component might detect and report an error condition while processing SQL statements that refer to one or more DRDA database tables. This means that error situations can be complex, involving error codes and supporting data from multiple components. In all cases, however, the application ultimately receives a single Oracle error number or return code upon which to act.
Because most gateway messages exceed the 70 character message area in the Oracle SQLCA, the programmatic interfaces and Oracle Call Interfaces that you use to access data through the gateway should use SQLGLM or OERHMS to view the entire text of messages. Refer to the programmer’s guide to the Oracle precompilers for additional information about SQLGLM, and see the Oracle C++ Call Interface Programmer's Guide for additional information about OERHMS. The error messages listed below apply to both TCP/IP and SNA networking communications products on the gateway.
Error conditions encountered when using the gateway can originate from many sources:
Errors detected by the Oracle integrating server
Errors detected by the gateway
Errors detected in the DRDA software, either on the requestor or server side
Communication errors
Errors detected by the server database
Errors detected by the Oracle integrating server are reported back to the application or tool with the standard "ORA-" type message. Refer to Oracle Database Error Messages for descriptions of these errors. For example, the following error message occurs when an undefined database link name is specified:
ORA-02019: connection description for remote database not found
Errors in the ORA-9100 to ORA-9199 range are reserved for the generic gateway layer (components of the gateway that are not specific to DRDA). Messages in this range are documented in Oracle Database Error Messages.
Errors detected by the generic gateway are prefixed with "HGO-" and are documented in Oracle Database Error Messages.
An example error message is:
HGO-00706: HGO: Missing equal sign for parameter in initialization file.
Errors detected in the DRDA gateway, on the requestor or server side, are usually reported with error ORA-28500, followed by a gateway-specific expanded error message. There are two return codes reported in the expanded message:
drc specifies DRDA-specific errors which are documented in "Gateway Error Codes".
grc specifies generic gateway errors detected in the DRDA layer. These errors are documented in the Oracle Database Error Messages.
The values in parentheses that follow the drc values are used for debugging by Oracle Support Services. The errp field indicates the program (requestor or server) that detected the error. If present, errmc lists any error tokens.
For example, the following error message is returned when the database name specified (XNAME) with the DRDA_REMOTE_NAME parameter in the initsid.ora file is not defined at the DRDA Server:
ORA-28500: connection from ORACLE to a non-Oracle system returned the message: TG4DRDA v10.1.0.2.0 grc=0, drc=-30061 (839C,0000), errp=GDJRFS2E errmc=XNAME
Communication errors are reported with an ORA-28501 followed by a gateway-specific expanded error message with drc=-30080 (SNA CPI-C error) or drc=-30081 (lost session). errmc indicates which CPI-C routine encounters the error, followed by the CPI-C error code and error number.
For example, the following error message is returned when there is a failure to establish a session because DRDA_CONNECT_PARM in the initsid.ora file specifies a Side Information Profile that is not defined:
ORA-28501: communication error on heterogeneous database link TG4DRDA v10.1.0.2.0 grc=0, drc=-30081 (839C,0001), errp= file or directory(2) errmc=Initialize_Conversation (CMINIT) CM_PROGRAM_PARAMETER_CHECK(24) No such > file or directory(2)
Refer to the appropriate host operating system, or SNA server documentation for more information.
Errors detected by the server database are reported with an ORA-28500 followed by a gateway-specific expanded error message with drc=-777 (sqlcode follows.) This is followed by another error message line that contains the sqlcode, sqlstate, errd (error array), and errmc (error tokens) returned from the DRDA Server database. Refer to IBM documentation for the specific database being used. Also refer to Mapped Errors in this chapter for some SQL errors that get translated.
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Note: Error code ORA-28500 was error code ORA-09100 prior to gateway version 8. Error code ORA-28501 was error code ORA-09101 prior to gateway version 8. |
For example, the following error message indicates that the DRDA Server database did not recognize the collection ID or package name specified with the DRDA_PACKAGE_COLLID or DRDA_PACKAGE_NAME parameters in the initsid.ora file:
ORA-28500: connection from ORACLE to a non-Oracle system returned the message: TG4DRDA v10.1.0.2.0 grc=0, drc=-30020 (839C,0000), errp=GDJMRCM sqlcode=-805, sqlstate=51002, errd=FFFFFF9C,0,0,FFFFFFFF,0,0 errmc=124c
Some SQL errors are returned from the DRDA Server database and are translated to an Oracle error code. This is needed when the Oracle instance or gateway provides special handling of an error condition. The following table lists the mapped sqlstate error numbers, descriptions, and their corresponding Oracle error codes:
Table 17-1 Mapped sqlstate Errors
The following is an example of a translated "object does not exist" error:
ORA-00942: table or view does not exist TG4DRDA v10.1.0.2.0 grc=0, drc=-942 (839C,0001), errp=DSNXEDST sqlcode=-204, sqlstate=52004, errd=32,0,0,FFFFFFFF,0,0 errmc=AJONES.CXDCX
Listed below are the common Oracle Transparent Gateway for DRDA error codes that appear in the drc= field of the expanded error messages. If you obtain a drc value that does not appear here, contact Oracle Support Services.
sqlcode and sqlstate indicate host database error. Use this information to fix your application.When developing applications it is often useful to be able to see the exact SQL statements that are being passed through the Gateway. This section describes setting appropriate trace parameters and setting up the debug Gateway.
The Oracle Database server has a command for capturing the SQL which is actually sent to the gateway. This command is called EXPLAIN PLAN. EXPLAIN PLAN is used to determine the execution plan that Oracle follows to execute a specified SQL statement. This command inserts a row (describing each step of the execution plan) into a specified table. If you are using cost-based optimization, this command also determines the cost of executing the statement. The syntax of the command is:
EXPLAIN PLAN [ SET STATEMENT_ID = 'text' ]
[ INTO [schema.]table[@dblink] ] FOR statement
For detailed information on this command, refer to the Oracle Database SQL Reference.
The production gateway does not have tracing built into it for the purpose of enhancing its speed. The product ships with a debug library that can be used to build a debug gateway for the purposes of tracing and debugging of applications.
First, login as the Admin user ID of the gateway and setup the environment:
$ su - <Gateway-Admin-User>
Next, build the debug gateway:
$ cd $ORACLE_HOME/tg4drda/lib $ make -f tg4drda.mk ORACLE_HOME=your_oracle_home g4drsrvd
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Note: ORACLE_HOME is the location of your gateway installation. That is to say,"your_oracle_home" is the ORACLE_HOME of the gateway, as set in "Step 3: Set the ORACLE_HOME environment variable" in Chapter 4, " Installing the Gateway". |
This will create the debug gateway and store it in $ORACLE_HOME/bin/g4drsrvd. Next, change the listener.ora to invoke the debug gateway. Using our example from Appendix B, " Sample Files", change the PROGRAM parameter to specify the debug program name:
(SID_DESC=
(SID_NAME=drdahoa1)
(ORACLE_HOME=/oracle/tg4drda/10.1.0)
(PROGRAM=g4drsrvd))
The listener will need to be reloaded for this change to take effect. Next, edit the gateway initialization file and add the following parameters:
You may optionally add the LOG_DESTINATION parameter, but it is not required.
The following is a fragment of a Gateway Initialization File with the parameters set:
# TRACE_LEVEL=255 ORACLE_DRDA_TCTL=debug.tctl #
The above example will give full tracing of both gateway and DRDA tracing. In many cases, only the gateway tracing is desirable. To obtain only gateway tracing, remove (or comment out) the "ORACLE_DRDA_TCTL" parameter.
If you specify a LOG_DESTINATION, you may specify just the file name (for example, "drda.trc"), in which case the log will be written to the gateway’s log directory ($ORACLE_HOME/tg4drda/log). Or you may specify a fully qualified path name. If you do not specify a LOG_DESTINATION, a unique log file in a default format will be generated.
The logfile name will be of the form:
gatewaysid_pid.trc
where:
gatewaysid is the SID of the gateway. The value of this is determined by the setting of the FDS_INSTANCE parameter, and pid is the process identifier (PID) of the gateway process.
An example log file name would be:
drdahoa1_3875.trc
When searching for the SQL statements which are passed to the DRDA Server, look for the strings '*** HGAPARS ***' and '*** HGAXMSQL ***'. The string after HGAPARS will be the incoming statement from the Oracle Database 10g RDBMS. The string after HGAXMSQL will be the outgoing statement after any date substitution is done. This is the actual SQL statement which will be given to the DRDA Server.
When you are done developing your application, revert the PROGRAM= value in the listener.ora to its previous value and reload the listener in order to use the production gateway again. You should also comment out the trace parameters in the Gateway Initialization Files.
