Major - P3 When loading RDD of an empty mongo collection, an uncatched exception is raised.
org.bson.BsonInvalidOperationException: Document does not contain key avgObjSize at org.bson.BsonDocument.throwIfKeyAbsent(BsonDocument.java:798) ~[mongo-java-driver-3.2.2.jar:na] at org.bson.BsonDocument.getNumber(BsonDocument.java:160) ~[mongo-java-driver-3.2.2.jar:na] at com.mongodb.spark.rdd.partitioner.MongoSamplePartitioner.partitions(MongoSamplePartitioner.scala:84) ~[mongo-spark-connector_2.11-2.0.0.jar:2.0.0] at com.mongodb.spark.rdd.partitioner.DefaultMongoPartitioner.partitions(DefaultMongoPartitioner.scala:34) ~[mongo-spark-connector_2.11-2.0.0.jar:2.0.0]
Looking at failing code in MongoSamplePartitioner.scala:84 it shows that a partitioner is trying to determine the number of partitions based on the amount of documents in the collection and the average size of them. However when the collection is empty a collStats mongodb command does not return avgObjSize key in it's results, causing the org.bson.BsonInvalidOperationException: Document does not contain key avgObjSize exception