diff --git a/examples/columnar.rs b/examples/columnar.rs
index 2f7b71909..81c39eec8 100644
--- a/examples/columnar.rs
+++ b/examples/columnar.rs
@@ -43,8 +43,8 @@ fn main() {
             let data = data_input.to_stream(scope);
             let keys = keys_input.to_stream(scope);
 
-            let data_pact = ExchangeCore::<ColumnBuilder<((String,()),u64,i64)>,_>::new_core(|x: &((&str,()),&u64,&i64)| (x.0).0.len() as u64);
-            let keys_pact = ExchangeCore::<ColumnBuilder<((String,()),u64,i64)>,_>::new_core(|x: &((&str,()),&u64,&i64)| (x.0).0.len() as u64);
+            let data_pact = ExchangeCore::<ColumnBuilder<((String,()),u64,i64)>,_>::new_core(|x: &((&str,()),&u64,&i64)| (x.0).0.as_bytes().iter().sum::<u8>() as u64);
+            let keys_pact = ExchangeCore::<ColumnBuilder<((String,()),u64,i64)>,_>::new_core(|x: &((&str,()),&u64,&i64)| (x.0).0.as_bytes().iter().sum::<u8>() as u64);
 
             let data = arrange_core::<_,_,Col2KeyBatcher<_,_,_>, ColKeyBuilder<_,_,_>, ColKeySpine<_,_,_>>(&data, data_pact, "Data");
             let keys = arrange_core::<_,_,Col2KeyBatcher<_,_,_>, ColKeyBuilder<_,_,_>, ColKeySpine<_,_,_>>(&keys, keys_pact, "Keys");
@@ -447,7 +447,9 @@ pub mod batcher {
                 }
             }
 
-            self.ready.push_back(std::mem::take(&mut self.empty));
+            if !self.empty.is_empty() {
+                self.ready.push_back(std::mem::take(&mut self.empty));
+            }
         }
     }
 }