Replication Guide and Reference

Apply program problem determination facilities

SQL and Apply program error messages can be found in the Apply trail table and the Apply program trace file. There is one trace file at the server associated with the Apply program. The Apply program log file tracks the activities of the Apply program and can be a useful diagnosis tool.

The Apply trail table

There is an Apply trail table (ASN.IBMSNAP_APPLYTRAIL) located at each control server with the subscription control tables, such as ASN.IBMSNAP_SUBS_SET. The Apply program inserts a new row in the Apply trail table every time it attempts to replicate a subscription. There is a row for all successful and unsuccessful subscription cycles of each replication subscription. For a description of the ASN.IBMSNAP_APPLYTRAIL table, see Table structures.

The Apply trail table records one SQL code and one SQL state for a replication subscription that does not get replicated successfully. Additional SQL codes and states associated with the problem can be found in the Apply program trace file.

You can query the Apply trail table for information about successful and unsuccessful replications. Some key fields in the table that have problem indicators are:

STATUS: Contains -1 to indicate a failed execution.
SQLSTATE: Contains the error SQLSTATE for a failed execution.
SQLCODE: Contains the error SQLCODE for a failed execution.
SQLERRM: Contains the text of the SQL error message.
APPERRM: Contains the text of the Apply program error message.

Within the error message text, determine which database the Apply program was connected to when the error occurred; for example, did the error occur while the Apply program was connected to the source server or the copy server?

The Apply trail table has fields that identify the source and target databases and tables so that you can locate the Apply trail control rows that are causing replication errors. To reduce the number of rows that you examine, you can:

Delete all rows from the Apply trail table, to clean out rows from past replications, before starting the Apply program.
Temporarily disable replications that are successful in order to capture rows in the Apply trail table only for replications that have problems before starting the Apply program.

An example query for the ASN.IBMSNAP_APPLYTRAIL is:

SELECT * FROM ASN.IBMSNAP_APPLYTRAIL
SELECT TARGET_TABLE, STATUS, SQLSTATE, SQLCODE, SQLERRM, APPERRM
FROM ASN.IBMSNAP_APPLYTRAIL

Apply program trace file

The Apply program creates a trace file when the Apply program trace invocation parameter is used. See the Capture and Apply chapter for your platform in this book for the Apply program invocation command.

If you specify a trace option, specify the name of a trace output file and, for workstation systems, precede the output file name with a pipe symbol (>). For example, to start Apply for Windows with trace, issue the following command from the command line processor window:

\APPLY>asnapply myapply mydbnt2 trcflow > apply.trc

Where:

myapply: is the Apply qualifier.
mydbnt2: is the control server where the Apply program finds the control tables.
trcflow: indicates that the Apply program traces all error and flow information.
apply.trc: is the file to which the output is directed.

The trace file is located in the same directory from which the Apply program is started.

After the Apply program is stopped, you can view the trace file with any editor. You can also transmit the file to other systems, such as by FTP, or print it.

You have two trace options:

TRCFLOW: Provides very detailed information and is oriented toward helping IBM Service diagnose errors. When using TRCFLOW, we suggest isolating the subscription error, such as by running it in a test environment or disabling other error-free replication subscriptions to reduce the volume of information.
TRCERR: Provides less detail and is a better choice when you are new to the replication tools.

Within the trace, particularly with the TRCFLOW option, entries are made into the trace file for the Apply program's activities. The following are examples of the recorded information:

Connecting to the control server to obtain information on replication subscriptions to be processed
Connecting to source servers to fetch rows to be replicated from the CD table to the target table
Connecting to the target servers to insert, update, and delete rows into and from the target tables

The Apply program inserts error messages and indicators in the trace file at points when it encounters an error.

The Apply program log file

The Apply program also has a log file containing messages with a summary of the Apply program's activities. The log file is in the same directory from which the Apply program is started and where the *.SPL file and any trace files are located.

The name of the Apply program log file is the Apply qualifier associated with the control server with the extension of *.APP. For example, for an Apply program operating with Apply qualifier MYAPPLY, the log file name is MYAPPLY.APP.

Because the Apply program log file information is high level, it typically directs you to the ASN.IBMSNAP_APPLYTRAIL table for more detailed information.

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