diff --git a/common/core/src/main/java/zingg/common/core/executor/Matcher.java b/common/core/src/main/java/zingg/common/core/executor/Matcher.java
index e222ce97c..6fb794665 100644
--- a/common/core/src/main/java/zingg/common/core/executor/Matcher.java
+++ b/common/core/src/main/java/zingg/common/core/executor/Matcher.java
@@ -189,7 +189,7 @@ protected ZFrame<D,R,C> getObvDupePairs(ZFrame<D,R,C> blocked) {
 			return null;
 		}
 		
-		ZFrame<D, R, C> obvDupePairs = blocked.joinOnCol(prefixedColsDF, obvDupeDFFilter);
+		ZFrame<D, R, C> obvDupePairs = blocked.joinOnCol(prefixedColsDF, obvDupeDFFilter).cache();
 		obvDupePairs = obvDupePairs.filter(obvDupePairs.gt(ColName.ID_COL));
 		obvDupePairs = massageAllEquals(obvDupePairs);