I have a script that generates command line invocations of rrdtool xport based on input provided in a domain specific language. This works well, until the number of DEFs in the command line exceed a certain number - it seems to be around 50. At that point the command simply returns without any output or error information.
Is there a limit on the number of DEFs in rrdtool export? If so, then can it be raised or circumvented?
The issue turned out to be the character limit on the command line sent to the shell via Python's os.system method call. The issue can be worked around by creating a temporary executable script, writing the command line to the script and executing it.