ASTERIXDB-1415 Fix Feed Freeze with Indexed Dataset A feed might cause the system to freeze when connected to a dataset that has secondary indexes. This case happen if a frame contains all duplicate records pass the primary index insert operator. The root cause is that the assign runtime in the pipeline assumes at least a single record. Hence, a corrupted tuple will reach the commit operator which will create a bad log record with a PK of size 0. The log record will cause the log flusher thread to die.