diff --git a/src/hnsw.h b/src/hnsw.h
index 8a9a2db..7ec79ce 100644
--- a/src/hnsw.h
+++ b/src/hnsw.h
@@ -377,7 +377,7 @@ typedef struct HnswVacuumState
 int			HnswGetM(Relation index);
 int			HnswGetEfConstruction(Relation index);
 FmgrInfo   *HnswOptionalProcInfo(Relation index, uint16 procnum);
-Datum		HnswNormValue(const HnswTypeInfo * typeInfo, Datum value);
+Datum		HnswNormValue(const HnswTypeInfo * typeInfo, Oid collation, Datum value);
 bool		HnswCheckNorm(FmgrInfo *procinfo, Oid collation, Datum value);
 Buffer		HnswNewBuffer(Relation index, ForkNumber forkNum);
 void		HnswInitPage(Buffer buf, Page page);
diff --git a/src/hnswbuild.c b/src/hnswbuild.c
index d6c3f1f..ee94ed9 100644
--- a/src/hnswbuild.c
+++ b/src/hnswbuild.c
@@ -498,7 +498,7 @@ InsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heaptid, Hn
 		if (!HnswCheckNorm(buildstate->normprocinfo, buildstate->collation, value))
 			return false;
 
-		value = HnswNormValue(typeInfo, value);
+		value = HnswNormValue(typeInfo, buildstate->collation, value);
 	}
 
 	/* Get datum size */
diff --git a/src/hnswinsert.c b/src/hnswinsert.c
index ad75fa5..0023024 100644
--- a/src/hnswinsert.c
+++ b/src/hnswinsert.c
@@ -630,7 +630,7 @@ HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_ti
 		if (!HnswCheckNorm(normprocinfo, collation, value))
 			return;
 
-		value = HnswNormValue(typeInfo, value);
+		value = HnswNormValue(typeInfo, collation, value);
 	}
 
 	HnswInsertTupleOnDisk(index, value, values, isnull, heap_tid, false);
diff --git a/src/hnswscan.c b/src/hnswscan.c
index 34bb6dd..6daf34d 100644
--- a/src/hnswscan.c
+++ b/src/hnswscan.c
@@ -61,7 +61,7 @@ GetScanValue(IndexScanDesc scan)
 
 		/* Fine if normalization fails */
 		if (so->normprocinfo != NULL)
-			value = HnswNormValue(so->typeInfo, value);
+			value = HnswNormValue(so->typeInfo, so->collation, value);
 	}
 
 	return value;
diff --git a/src/hnswutils.c b/src/hnswutils.c
index d1ada70..48acef0 100644
--- a/src/hnswutils.c
+++ b/src/hnswutils.c
@@ -156,9 +156,9 @@ HnswOptionalProcInfo(Relation index, uint16 procnum)
  * Normalize value
  */
 Datum
-HnswNormValue(const HnswTypeInfo * typeInfo, Datum value)
+HnswNormValue(const HnswTypeInfo * typeInfo, Oid collation, Datum value)
 {
-	return DirectFunctionCall1(typeInfo->normalize, value);
+	return DirectFunctionCall1Coll(typeInfo->normalize, collation, value);
 }
 
 /*