During a high memory load on the TIBCO Data Virtualization Server, it is observed that TDV monitor stops running. The cs_monitor.log file shows the following message:

INFO 2020-11-05 12:20:03.652 -0500 ServerBootExecutor - The server 'localhost:9400' is OPERATIONAL.
INFO 2020-11-05 12:21:19.443 -0500 ServerBootExecutor - Server stopped. ExitCode = 137.
INFO 2020-11-05 12:21:19.444 -0500 ServerBootExecutor - The server 'localhost:9400' is STOPPED.

The message "Server stopped. ExitCode = 137" is due to a "kill -9" conducted on the the TDV Server process. As the kill -9 command was not deliberately performed by a user, an OOM condition most likely occurred on the host and the kernel simply killed the most memory hungry process. When TDV realized, it started the monitor process again by itself.
As best practices, it is recommended to set “Total Available Memory (On Server Restart)” to a maximum of 85% of the total memory available on the TDV Server host machine, considering there are no other services running on the host machine of TDV. This helps from an OOM error not to occur due to near to complete use of the available memory on the host machine.

To resolve this issue:
(1) Decrease the memory assigned to TDV by altering the configuration from Studio > Administration > Configuration > Server > Memory > Java Heap > Total Available Memory (On Server Restart) = your desired value.
(2) If the TDV instance is using the <TDV Install directory>\conf\evn_script.sh file then alter the memory changes in the environment file as well.
(3) Perform a TDV Server restart for the new value to take effect.