Ok, that's interesting.  The nonsense-looking symbol up the top is probably jitted code from your query, probably an expression or something like that.    36.50%  perf-18476.map                 [.] 0x00007f3c1d634b82                                                                                                                                             The other symbols like GetDoubleVal() may be what is calling this expensive function. It looks like it's possible ProbeTime in the profile that's the culprit.   Can you share the SQL for your query at all? I'm guessing that there's some expression in your query that's expensive to evaluate. E.g. joining on some complex expression, or doing some kind of expensive computation.   ... View more

Yes, that's right. It's enabled for some cases by default (broadcast joins) in Impala 2.5. To enable it for a wider category of joins you can set the query option runtime_filter_mode=global.  This setting will become the default in Impala 2.7 because of the performance benefits. ... View more

Impala limits the number of threads executing the query plan by design. Impala dynamically increases the number of scanner threads provided there are CPU and memory resources available - in this case it seems like there weren't CPU resource available.   If the machine is already busy adding more threads can actually decrease query throughput. ... View more