First-failure data capture

The iSeries™ server provides a way for you to capture and report error information for the distributed relational database. This function is called first-failure data capture (FFDC).

The primary purpose of FFDC support is to provide extensive information on errors detected in the DDM components of the i5/OS™ operating system from which an Authorized Program Analysis Report (APAR) can be created.

You can also use this function to help you diagnose some system-related application problems. By means of this function, key structures and the DDM data stream are automatically dumped to the spooled file. The goal of this automatic dumping of error information on the first occurrence of an error is to minimize the need to have to create the failure again to report it for service support. FFDC is active in both the application requester and the application server.

One thing you should keep in mind is that not all negative SQLCODEs result in dumps; only those that might indicate an APAR situation are dumped.

• A first-failure data capture dump
  System-detected internal failures trigger first-failure data capture (FFDC) data to be dumped. FFDC output can be disabled by setting the QSFWERRLOG system value to *NOLOG, but it is strongly recommended that you do not disable the FFDC dump process.
• FFDC dump output description
  This information describes the data areas and types of information available in a first-failure data capture (FFDC) dump output.
• DDM error codes
  These error codes are included in the FFDC dumps (L in the sample dump output) that identify DDM error conditions. These conditions might or might not be defined by the DDM architecture.