From 6a0405de2047c344ec6f3d0f6a61c19b2c146483 Mon Sep 17 00:00:00 2001
From: Himanshu Gupta <g.himanshu@gmail.com>
Date: Sat, 7 Mar 2015 12:45:57 -0600
Subject: [PATCH] fail early if there is no input data for batch hadoop
 indexing

---
 .../src/main/java/io/druid/indexer/IndexGeneratorJob.java   | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java b/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java
index c944886124d..73634382059 100644
--- a/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java
+++ b/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java
@@ -169,7 +169,11 @@ public class IndexGeneratorJob implements Jobby
 
       SortableBytes.useSortableBytesAsMapOutputKey(job);
 
-      job.setNumReduceTasks(Iterables.size(config.getAllBuckets().get()));
+      int numReducers = Iterables.size(config.getAllBuckets().get());
+      if(numReducers == 0) {
+        throw new RuntimeException("No buckets?? seems there is no data to index.");
+      }
+      job.setNumReduceTasks(numReducers);
       job.setPartitionerClass(IndexGeneratorPartitioner.class);
 
       setReducerClass(job);