4-10 IBM Informix OnLine Database Server Administrator’s Guide
Setting Consistency-Checking Variables
(Acore dump is an image of the database server process in memory at the time
that the inconsistency was detected. Some core dumps include a copy of
sharedmemory. To determine the size of your OnLine sharedmemory, refer
to the kilobyte information listed in anytbstat header.)
Administratorswith 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.
GCORE
TheGCORE environment variable is used with UNIX operating systems that
supportthe gcore utility. If GCORE is set, the OnLine database server process
calls gcore whenever the server process detects an inconsistency or initiates
an abort sequence. The gcore utility directs the server process to dump core
tothe current directory (or the directory specified by DUMPDIR) and continue
processing.
The core dump output generated bygcore is saved to the file core.pid.cnt.
Thepid value is the OnLine database server process identification number.
Thecnt value is incremented each time this process encounters an inconsis-
tency. Thecnt value can range from 1 to 4. After 4, separate core dumps are
savedto files, and no more files are created. If the server process continues to
detect inconsistencies in this section of code, errors are reported to the
OnLine message log (and perhaps to the application), but no further
diagnostic information is saved.
Ifyou set GCORE and your UNIX system does not support gcore, messages in
theOnLine message log indicate that an attempt was made to dump core, but
theexpected file was not found. (If your UNIX system does not support gcore,
setDUMPCORE instead.)
Setthe GCORE environment variable at the system prompt or in your .login
or.cshrc (C shell) or your .profile (Bourne shell) file as follows:
C shell: setenv GCORE
Bourne shell: GCORE =
export GCORE