Fixes

fix NPE in select query, calculating cache key
remove unwanted logging
fix ds in topNQuery

indexing-hadoop/src/main/java/io/druid/indexer/DeterminePartitionsJob.java

@@ -762,8 +762,6 @@ public class DeterminePartitionsJob implements Jobby
         log.info("  %s", HadoopDruidIndexerConfig.jsonMapper.writeValueAsString(shardSpec));
       }
 
-      System.out.println(HadoopDruidIndexerConfig.jsonMapper.writeValueAsString(chosenShardSpecs));
-
       try {
         HadoopDruidIndexerConfig.jsonMapper
                                 .writerWithType(

processing/src/main/java/io/druid/query/UnionDataSource.java

@@ -43,6 +43,9 @@ public class UnionDataSource implements DataSource
   public UnionDataSource(@JsonProperty("dataSources") List<DataSource> dataSources)
   {
     Preconditions.checkNotNull(dataSources, "datasources cannot be null for uniondatasource");
+    for(DataSource ds : dataSources){
+      Preconditions.checkArgument(ds instanceof TableDataSource, "Union DataSource only supports TableDatasource");
+    }
     this.dataSources = dataSources;
   }
 

processing/src/main/java/io/druid/query/select/PagingSpec.java

@@ -40,7 +40,7 @@ public class PagingSpec
       @JsonProperty("threshold") int threshold
   )
   {
-    this.pagingIdentifiers = pagingIdentifiers;
+    this.pagingIdentifiers = pagingIdentifiers == null ? new LinkedHashMap<String, Integer>() : pagingIdentifiers;
     this.threshold = threshold;
   }
 

processing/src/main/java/io/druid/query/topn/TopNQuery.java

@@ -167,7 +167,7 @@ public class TopNQuery extends BaseQuery<Result<TopNResultValue>>
   public Query<Result<TopNResultValue>> withDataSource(DataSource dataSource)
   {
     return new TopNQuery(
-        getDataSource(),
+        dataSource,
         dimensionSpec,
         topNMetricSpec,
         threshold,