I ran the query from the command line and piped the results. At the bottom are them two numbers: Timer 197.414 msec Timer 1.690 msec I'm assumming one represents the runtime, not sure about the other. I also ran the query with trace. At the bottom it says: Timer 245.435 msec Timer 1.380 msec In the trace file here are the 13 biggest lines: [ 243 usec # _16 := nil; ] [ 251 usec # _31 := nil; ] [ 1538 usec # _30 := algebra.join(_27=<~tmp_21501>bat[:oid,:oid]{176871}, _28=<tmp_16674>bat[:oid,:oid]{4000000}) ] [ 1877 usec # _104 := algebra.joinPath(_60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _102=<tmp_13260>bat[:oid,:str]{32}) ] [ 1883 usec # _121 := algebra.joinPath(_112=<tmp_21470>bat[:oid,:oid]{89}, _60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _97=<tmp_13261>bat[:oid,:str]{32}) ] [ 1885 usec # _122 := algebra.joinPath(_112=<tmp_21470>bat[:oid,:oid]{89}, _60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _102=<tmp_13260>bat[:oid,:str]{32}) ] [ 1900 usec # _120 := algebra.joinPath(_112=<tmp_21470>bat[:oid,:oid]{89}, _60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _17=<tmp_11202>bat[:oid,:str]{32}) ] [ 1906 usec # _119 := algebra.joinPath(_112=<tmp_21470>bat[:oid,:oid]{89}, _60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _89=<tmp_10351>bat[:oid,:str]{32}) ] [ 1910 usec # _94 := algebra.joinPath(_60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _17=<tmp_11202>bat[:oid,:str]{32}) ] [ 1969 usec # _91 := algebra.joinPath(_60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _89=<tmp_10351>bat[:oid,:str]{32}) ] [ 1979 usec # _99 := algebra.joinPath(_60=<~tmp_21352>bat[:oid,:oid]{89}, _43=<~tmp_21452>bat[:oid,:oid]{1304}, _88=<~tmp_21522>bat[:oid,:oid]{176871}, _97=<tmp_13261>bat[:oid,:str]{32}) ] [ 3256 usec # sql.exportResult(_197=0, _242="") ] [ 4921 usec # _39 := algebra.join(_38=<tmp_21352>bat[:oid,:oid]{210}, _31=<~tmp_21452>bat[:oid,:oid]{176871}) ] [ 73885 usec # _23 := algebra.semijoin(_16=<~tmp_13761>bat[:oid,:oid]{4000000}, _20=<tmp_21501>bat[:oid,:oid]{1}) ] (the above is piped through sort, not the last one is an order of magnitude bigger than anything else). How do I go about starting to understand/debug this?