River has returned no metrics but instead [Poison<<esrally.driver.StartBenchmark

I'm trying to run my own track using 'esrally --pipeline=from-distribution --distribution-version=1.7.1 --track=merchants_original --offline' but I'm getting the following error:

Traceback (most recent call last):
File "/home/ubuntu/.local/lib/python3.5/site-packages/esrally/racecontrol.py", line 364, in run
File "/home/ubuntu/.local/lib/python3.5/site-packages/esrally/racecontrol.py", line 60, in call
File "/home/ubuntu/.local/lib/python3.5/site-packages/esrally/racecontrol.py", line 29, in call
File "/home/ubuntu/.local/lib/python3.5/site-packages/esrally/racecontrol.py", line 145, in benchmark_internal
raise exceptions.RallyError("Driver has returned no metrics but instead [%s]. Terminating race without result." % str(completed))
esrally.exceptions.RallyError: Driver has returned no metrics but instead [Poison<<esrally.driver.StartBenchmark object at 0x7fb9b5800978>>]. Terminating race without result.

What does this mean? How can I debug this futher?

Hi @gregsterin,

this is very likely a problem that happened while running the track. One problem could be that your track has a syntax error. Does it work with the default tracks?

Can you please check / share the log files of this race? They are located in /home/ubuntu/.rally/benchmarks/races/$TIMESTAMP/local/logs/.

I've created https://github.com/elastic/rally/issues/153 so Rally will provide a more helpful message in these cases.


@danielmitterdorfer - I was able to find the cause here. In my case it was that I needed to specify the --challenge= that I wanted to run, since the default challenge name was not in my track.

+1 on more helpful error messages here. In this case, if it told me "Did not find target challenge [CHALLENGE] in [TRACK]", I would have known what was wrong with less confusion.

Hi @gregsterin,

great that you could identify the root cause. I try to get the improvement done in one of the releases of 0.4.x.