diff --git a/client/src/main/resources/log4j.properties b/client/src/main/resources/log4j.properties
index 27f59c28b..37678b3b0 100644
--- a/client/src/main/resources/log4j.properties
+++ b/client/src/main/resources/log4j.properties
@@ -28,8 +28,8 @@ log4j.logger.org.elasticsearch.hadoop=WARN
 log4j.logger.akka=WARN, FILE
 log4j.logger.breeze=WARN, FILE
 log4j.logger.zingg=INFO
-log4j.logger.zingg.hash=INFO
-log4j.logger.zingg.block.Block=INFO
+log4j.logger.zingg.hash=DEBUG
+log4j.logger.zingg.block=DEBUG
 log4j.logger.zingg.Matcher=INFO
 log4j.logger.zingg.Model=INFO
 log4j.logger.com.datastax.spark=WARN
diff --git a/core/src/main/java/zingg/block/Block.java b/core/src/main/java/zingg/block/Block.java
index d04b30a3e..4a53ba247 100644
--- a/core/src/main/java/zingg/block/Block.java
+++ b/core/src/main/java/zingg/block/Block.java
@@ -346,6 +346,9 @@ public static List<Canopy> getHashSuccessors(Collection<Canopy> successors, Obje
 	public static StringBuilder applyTree(Row tuple, Tree<Canopy> tree,
 			Canopy root, StringBuilder result) {
 		if (root.function != null) {
+			if (LOG.isDebugEnabled()) {
+				LOG.debug("applying " + root.function);
+			}
 			Object hash = root.function.apply(tuple, root.context.fieldName);
 			
 			result = result.append("|").append(hash);
@@ -400,6 +403,9 @@ public BlockFunction(Tree<Canopy> tree) {
 		@Override
 		public Row call(Row r) {
 			StringBuilder bf = new StringBuilder();
+			if (LOG.isDebugEnabled()) {
+				LOG.debug("blocking row " + r);
+			}
 			bf = Block.applyTree(r, tree, tree.getHead(), bf);
 			Seq<Object> s = r.toSeq();
 			List<Object> seqList = JavaConversions.seqAsJavaList(s);
diff --git a/core/src/main/java/zingg/hash/HashFunction.java b/core/src/main/java/zingg/hash/HashFunction.java
index 8a43caa28..2bcd2d96a 100644
--- a/core/src/main/java/zingg/hash/HashFunction.java
+++ b/core/src/main/java/zingg/hash/HashFunction.java
@@ -68,5 +68,17 @@ public Dataset<Row> apply(Dataset<Row> ds, String column, String newColumn) {
 		}
 		
 		public abstract Object apply(Row ds, String column);
+
+
+	@Override
+	public String toString() {
+		return "{" +
+			" dataType='" + getDataType() + "'" +
+			", name='" + getName() + "'" +
+			", isUdf='" + isUdf + "'" +
+			", returnType='" + getReturnType() + "'" +
+			"}";
+	}
+
 }