Assign default value to StackTrace
Assign default value to StackTrace


Former-commit-id: f6aa6c438af872656a2748308291589aec3aba91
larryxiao/peloton-1,ranxian/peloton,larryxiao/peloton-1,omegaga/peloton,amaliujia/CMUDB-peloton,larryxiao/peloton,larryxiao/peloton,larryxiao/peloton-1,ranxian/peloton,omegaga/peloton,omegaga/peloton,larryxiao/peloton,larryxiao/peloton,larryxiao/peloton-1,larryxiao/peloton,larryxiao/peloton-1,omegaga/peloton,ranxian/peloton,omegaga/peloton,amaliujia/CMUDB-peloton,ranxian/peloton,larryxiao/peloton-1,larryxiao/peloton-1,omegaga/peloton,amaliujia/CMUDB-peloton,ranxian/peloton,amaliujia/CMUDB-peloton,larryxiao/peloton,ranxian/peloton,amaliujia/CMUDB-peloton,omegaga/peloton,amaliujia/CMUDB-peloton,larryxiao/peloton,amaliujia/CMUDB-peloton