Pinot table with null value from time column isn't filled with default value in NullValueTransformer. Then during the index step in LLRealtimeSegmentDataManager:L502, exceptions are thrown because of the null value. This recently caused several our servers go down because of too many exceptions.

One solution is to remove the special case handling for time column.

BTW, curious why do we choose not to handle the null value in time column?

cc @chenboat