diff --git a/processing/src/main/java/io/druid/query/filter/ExtractionDimFilter.java b/processing/src/main/java/io/druid/query/filter/ExtractionDimFilter.java
index 6f996ea0da3..e88868673d6 100644
--- a/processing/src/main/java/io/druid/query/filter/ExtractionDimFilter.java
+++ b/processing/src/main/java/io/druid/query/filter/ExtractionDimFilter.java
@@ -82,7 +82,7 @@ public class ExtractionDimFilter implements DimFilter
   public byte[] getCacheKey()
   {
     byte[] dimensionBytes = StringUtils.toUtf8(dimension);
-    byte[] valueBytes = StringUtils.toUtf8(value);
+    byte[] valueBytes = value == null ? new byte[0] : StringUtils.toUtf8(value);
     byte[] extractionFnBytes = extractionFn.getCacheKey();
     return ByteBuffer.allocate(3 + dimensionBytes.length + valueBytes.length + extractionFnBytes.length)
                      .put(DimFilterCacheHelper.EXTRACTION_CACHE_ID)
diff --git a/processing/src/test/java/io/druid/query/filter/ExtractionDimFilterTest.java b/processing/src/test/java/io/druid/query/filter/ExtractionDimFilterTest.java
index 83bd406495d..03b26b24c4d 100644
--- a/processing/src/test/java/io/druid/query/filter/ExtractionDimFilterTest.java
+++ b/processing/src/test/java/io/druid/query/filter/ExtractionDimFilterTest.java
@@ -55,5 +55,7 @@ public class ExtractionDimFilterTest
     );
 
     Assert.assertFalse(Arrays.equals(extractionDimFilter2.getCacheKey(), extractionDimFilter3.getCacheKey()));
+
+    Assert.assertNotNull(new ExtractionDimFilter("foo", null, new RegexDimExtractionFn("xx", null, null), null));
   }
 }