Index: ql/src/java/org/apache/hadoop/hive/ql/optimizer/BucketMapJoinOptimizer.java =================================================================== --- ql/src/java/org/apache/hadoop/hive/ql/optimizer/BucketMapJoinOptimizer.java (revision 1038300) +++ ql/src/java/org/apache/hadoop/hive/ql/optimizer/BucketMapJoinOptimizer.java (working copy) @@ -255,10 +255,14 @@ Partition part = null; Iterator iter = prunedParts.getConfirmedPartns() .iterator(); - part = iter.next(); + if (iter.hasNext()) { + part = iter.next(); + } if (part == null) { iter = prunedParts.getUnknownPartns().iterator(); - part = iter.next(); + if (iter.hasNext()) { + part = iter.next(); + } } assert part != null; Integer num = new Integer(part.getBucketCount());