Data Consistency, Recovery, and Migration 4-11
Setting Consistency-Checking Variables
DUMPCORE
Set theDUMPCORE environmental variable as an alternative to GCORE for
systems that do not support thegcore utility. DUMPCORE directs each
OnLine database server process to dump core when it detects an inconsis-
tency or initiates an abort sequence. To accomplish this, the server process
sendsitself a segmentation violation signal. The result, which is a terminated
process that requires cleanup by an OnLine daemon process, is less elegant
than theGCORE option.
If you mistakenly set bothGCORE and DUMPCORE, the server process first
callsgcore, dumps core, then continues until the DUMPCORE variable directs
the process to dump core again and send itself a segmentation violation
signal.
IfDUMPCORE is set, you risk OnLine aborting whenever a user process
detects an inconsistency while it is in a critical section or holding a latch.
Set theDUMPCORE environment variable at the system prompt or in your
.login or.cshrc (C shell) or your .profile (Bourne shell) file as follows:
DUMPSHMEM
TheDUMPSHMEM environment variable directs the OnLine database server
process to save a copy of shared memory to a file in the current directory or
the directory specified byDUMPDIR.
The filename takes the formatshmem.pid.cnt. The pid value is the OnLine
databaseserver process identification number. The cnt value is incremented
each time this process encounters an inconsistency. Thecnt value can range
from 1 to 4. After 4 copies of shared memory are saved to separate files, no
morefiles 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.
C shell: setenv DUMPCORE
Bourne shell: DUMPCORE =
export DUMPCORE