Problem

-- during a peak of activity, the DML function runCommand returns a wrong value (ex : -1)

-- once a wrong value is returned, the function always returns the same wrong value

-- looking at the trace and logs, no memory error is thrown

Resolution

* the problem is probably caused by a memory issue

* identify the pid of the processing engine(s) handling the map

* run strace commands for each PE

strace -p <pid> -o strace_pid.txt

* open at the strace_pid.txt file and search for Out of memory exceptions

* add memory on the system, or configure the java setings (decrease Xmx / Xms) to avoid an extra consumption of the java process (which can lead C / MBC program to run out of memory)