Uses a temporary output_relation instead of TRUNCATE
Uses a temporary output_relation instead of TRUNCATE

and renames it after successfully executing the extractor.

HazyResearch/deepdive,shahin/deepdive,zifeishan/deepdive,zifeishan/deepdive,sky-xu/deepdive,sky-xu/deepdive,HazyResearch/deepdive,HazyResearch/deepdive,zifeishan/deepdive,HazyResearch/deepdive,zifeishan/deepdive,shahin/deepdive,zifeishan/deepdive