public MapJoinStreamingRelation getStreamingSide() {
RelMetadataQuery mq = RelMetadataQuery.instance();
Double leftInputSize = mq.memory(left);
Double rightInputSize = mq.memory(right);
if (leftInputSize == null && rightInputSize == null) {
return MapJoinStreamingRelation.NONE;
} else if (leftInputSize != null
&& (rightInputSize == null || (leftInputSize < rightInputSize))) {
return MapJoinStreamingRelation.RIGHT_RELATION;
} else if (rightInputSize != null
&& (leftInputSize == null || (rightInputSize <= leftInputSize))) {
return MapJoinStreamingRelation.LEFT_RELATION;
}
return MapJoinStreamingRelation.NONE;
}
