Hi,   I've upgraded Impala from 2.7.0 to 2.9.0 and one of my queries stopped working after that.   On running this query:   select first_value(transxref) over (partition by substr(gbm.transxref,1,(instr(gbm.transxref,'/'))-1) order by substr(gbm.transxref,1,(instr(gbm.transxref,'/'))-1), reportdate) from gbm_partition gbm   I  receive error: "IllegalStateException: null"   But if I will change order by clause and will run query below - it will work. select first_value(transxref) over (partition by substr(gbm.transxref,1,(instr(gbm.transxref,'/'))-1) order by transxref, reportdate) from gbm_partition gbm 1. Can anybody please suggest, if there are any incompatibilities between 2.7.0 and 2.9.0 (I haven't found anything in Release Notes)? 2. If there are - can anybody please suggest a workaround for this issue?   Thanks in advance, Anastasiia ... View more