diff --git a/src/datastruct/fstmap.rs b/src/datastruct/fstmap.rs
index 428e9b710..adb3e6e35 100644
--- a/src/datastruct/fstmap.rs
+++ b/src/datastruct/fstmap.rs
@@ -20,7 +20,7 @@ pub struct FstMapBuilder<W: Write, V: BinarySerializable> {
 }
 
 impl<W: Write, V: BinarySerializable> FstMapBuilder<W, V> {
-
+    
     pub fn new(w: W) -> io::Result<FstMapBuilder<W, V>> {
         let fst_builder = try!(fst::MapBuilder::new(w).map_err(convert_fst_error));
         Ok(FstMapBuilder {
@@ -50,6 +50,7 @@ impl<W: Write, V: BinarySerializable> FstMapBuilder<W, V> {
         Ok(())
     }
 
+    #[cfg(test)]
     pub fn insert(&mut self, key: &[u8], value: &V) -> io::Result<()> {
         try!(self.fst_builder
             .insert(key, self.data.len() as u64)
@@ -146,7 +147,6 @@ mod tests {
         assert_eq!(keys.next().unwrap(), "abc".as_bytes());
         assert_eq!(keys.next().unwrap(), "abcd".as_bytes());
         assert_eq!(keys.next(), None);
- 
     }
 
 }
diff --git a/src/postings/recorder.rs b/src/postings/recorder.rs
index 94173720b..05586858a 100644
--- a/src/postings/recorder.rs
+++ b/src/postings/recorder.rs
@@ -26,8 +26,6 @@ pub trait Recorder: HeapAllocable {
     fn record_position(&mut self, position: u32, heap: &Heap);
     /// Close the document. It will help record the term frequency.
     fn close_doc(&mut self, heap: &Heap);
-    /// Returns the number of document that have been seen so far
-    fn doc_freq(&self) -> u32;
     /// Pushes the postings information to the serializer.
     fn serialize(&self,
                  self_addr: u32,
@@ -41,7 +39,6 @@ pub trait Recorder: HeapAllocable {
 pub struct NothingRecorder {
     stack: ExpUnrolledLinkedList,
     current_doc: DocId,
-    doc_freq: u32,
 }
 
 impl HeapAllocable for NothingRecorder {
@@ -49,7 +46,6 @@ impl HeapAllocable for NothingRecorder {
         NothingRecorder {
             stack: ExpUnrolledLinkedList::with_addr(addr),
             current_doc: u32::max_value(),
-            doc_freq: 0u32,
         }
     }
 }
@@ -62,17 +58,12 @@ impl Recorder for NothingRecorder {
     fn new_doc(&mut self, doc: DocId, heap: &Heap) {
         self.current_doc = doc;
         self.stack.push(doc, heap);
-        self.doc_freq += 1;
     }
 
     fn record_position(&mut self, _position: u32, _heap: &Heap) {}
 
     fn close_doc(&mut self, _heap: &Heap) {}
 
-    fn doc_freq(&self) -> u32 {
-        self.doc_freq
-    }
-
     fn serialize(&self,
                  self_addr: u32,
                  serializer: &mut PostingsSerializer,
@@ -91,7 +82,6 @@ pub struct TermFrequencyRecorder {
     stack: ExpUnrolledLinkedList,
     current_doc: DocId,
     current_tf: u32,
-    doc_freq: u32,
 }
 
 impl HeapAllocable for TermFrequencyRecorder {
@@ -100,7 +90,6 @@ impl HeapAllocable for TermFrequencyRecorder {
             stack: ExpUnrolledLinkedList::with_addr(addr),
             current_doc: u32::max_value(),
             current_tf: 0u32,
-            doc_freq: 0u32,
         }
     }
 }
@@ -111,7 +100,6 @@ impl Recorder for TermFrequencyRecorder {
     }
 
     fn new_doc(&mut self, doc: DocId, heap: &Heap) {
-        self.doc_freq += 1u32;
         self.current_doc = doc;
         self.stack.push(doc, heap);
     }
@@ -126,10 +114,6 @@ impl Recorder for TermFrequencyRecorder {
         self.current_tf = 0;
     }
 
-    fn doc_freq(&self) -> u32 {
-        self.doc_freq
-    }
-
     fn serialize(&self,
                  self_addr: u32,
                  serializer: &mut PostingsSerializer,
@@ -154,7 +138,6 @@ impl Recorder for TermFrequencyRecorder {
 pub struct TFAndPositionRecorder {
     stack: ExpUnrolledLinkedList,
     current_doc: DocId,
-    doc_freq: u32,
 }
 
 impl HeapAllocable for TFAndPositionRecorder {
@@ -162,7 +145,6 @@ impl HeapAllocable for TFAndPositionRecorder {
         TFAndPositionRecorder {
             stack: ExpUnrolledLinkedList::with_addr(addr),
             current_doc: u32::max_value(),
-            doc_freq: 0u32,
         }
     }
 }
@@ -173,7 +155,6 @@ impl Recorder for TFAndPositionRecorder {
     }
 
     fn new_doc(&mut self, doc: DocId, heap: &Heap) {
-        self.doc_freq += 1;
         self.current_doc = doc;
         self.stack.push(doc, heap);
     }
@@ -186,10 +167,6 @@ impl Recorder for TFAndPositionRecorder {
         self.stack.push(POSITION_END, heap);
     }
 
-    fn doc_freq(&self) -> u32 {
-        self.doc_freq
-    }
-
     fn serialize(&self,
                  self_addr: u32,
                  serializer: &mut PostingsSerializer,