Collect diagnostic information

Several ONCONFIG parameters affect the way in which the database server collects diagnostic information. Because an assertion failure is generally an indication of an unforeseen problem, notify HCL Informix® Technical Support whenever one occurs. The diagnostic information collected is intended for the use of HCL Informix technical staff. The contents and use of af.xxx files and shared core are not further documented.

To determine the cause of the problem that triggered the assertion failure, it is critically important that you not delete diagnostic information until HCL Informix Technical Support indicates that you can do so. The af.xxx file often contains information that they require to resolve the problem.

Several ONCONFIG parameters direct the database server to preserve diagnostic information whenever an assertion failure is detected or whenever the database server enters into an end sequence:
  • DUMPDIR
  • DUMPSHMEM
  • DUMPCNT
  • DUMPCORE
  • DUMPGCORE

For more information about the configuration parameters, see the HCL Informix Administrator's Reference.

You decide whether to set these parameters. Diagnostic output can use a large amount of disk space. (The exact content depends on the environment variables set and your operating system.) The elements of the output can include a copy of shared memory and a core dump.
Tip: A core dump is an image of a process in memory at the time that the assertion failed. On some systems, core dumps include a copy of shared memory. Core dumps are useful only if this is the case.

Database server administrators with disk-space constraints might prefer to write a script that detects the presence of diagnostic output in a specified directory and sends the output to tape. This approach preserves the diagnostic information and minimizes the amount of disk space used.


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