Correcting assertion failures (AF)

An assertion failure occurs when the database server cannot continue normal processing and must shut down. You can correct some of the problems that cause assertion failures, such as disk issues. For other problems that cause assertion failures, you must contact IBM® Software Support.

If your production server is currently down, contact IBM Software Support immediately.

To correct an assertion failure:

1. Look at the online log for the assertion failure message.
   The location of the online log is specified by the MSGPATH configuration parameter. Default:

   • UNIX: $INFORMIXDIR/tmp/online.log
   • Windows: %INFORMIXDIR%\online.log
2. Perform any action mentioned in the assertion failure message. For example, you might need to run an oncheck command or increase the size of the physical or logical log buffer.
   The following table lists the common types of assertion failures and what you can do to correct the underlying problems.

   Table 1. Common types of assertion failures.

   Error	Cause	Solutions
   bfcheck	Corrupted data page, index, or partition page	Run the oncheck command in the assertion failure message. If an index is corrupted, drop and recreate the index. If a partition page is corrupted, you might need to restore the data.
   I/O write chunk	Not enough shared memory or a hardware problem	Look at your operating system logs for hardware problems or problems with other software. Sometimes other software can trigger an Informix® assertion failure. Fix any hardware or other software problems. Free up or increase shared memory for the database server.
   No exception handler	Memory corruption	Look at your operating system logs for hardware problems or problems with other software. Fix any hardware or other software problems.
   sigkill	The oninit daemon was stopped.	Restart the database server.
   segv sigbus	Memory corruption An ill-behaved C user-defined routine A defect in the database server	Look at your operating system logs for hardware problems or problems with other software. Fix any hardware or other software problems. If you use C user-defined routines, check your code for problems. Make sure that your user-defined routines follow the guidelines for well-behaved routines. If you are not running the latest Informix fix pack, check the latest Fixed and known defects file to see whether this issue is fixed. Upgrade to the latest Informix fix pack.

3. Restart the database server. Some assertion failures can be solved by the database server during startup.
4. If the database server does not start or the problem recurs, collect the following files for IBM Software Support in addition to the standard list of information to gather.

   Table 2. Files for support.

   File	Location
   assertion failure files: af.xxx, where xxx is the hexadecimal number associated with the failure	Specified by the DUMPDIR configuration parameter. Default: UNIX: $INFORMIXDIR/tmp Windows: %INFORMIXDIR%\tmp
   sqlhosts file	Specified by the INFORMIXSQLHOSTS environment variable. Default: UNIX: $INFORMIXDIR/etc Windows: registry
   onconfig file	Specified by the ONCONFIG environment variable. Default: UNIX: $INFORMIXDIR/etc Windows: %INFORMIXDIR%\etc
   online log file	Specified by the MSGPATH configuration parameter. Default: UNIX: $INFORMIXDIR/tmp/online.log Windows: %INFORMIXDIR%\online.log
   shared memory dump files:shmem.xxx, where xxx is the hexadecimal number associated with the failure	Specified by the DUMPDIR configuration parameter. Default: UNIX: $INFORMIXDIR/tmp Windows: %INFORMIXDIR%\tmp Generated only if the DUMPSHMEM configuration parameter is set to 1 or 2.

5. Contact IBM Software Support.

• Prevent and prepare for assertion failures
  You can perform routine administrative tasks that can prevent assertion failures or help prepare for recovering from assertion failures.

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