diff --git a/src/ivfbuild.c b/src/ivfbuild.c
index b42372f..edc435a 100644
--- a/src/ivfbuild.c
+++ b/src/ivfbuild.c
@@ -523,10 +523,13 @@ CreateListPages(Relation index, VectorArray centers, int dimensions,
 	{
 		OffsetNumber offno;
 
+		/* Zero memory for each list */
+		MemSet(list, 0, listSize);
+
 		/* Load list */
 		list->startPage = InvalidBlockNumber;
 		list->insertPage = InvalidBlockNumber;
-		memcpy(&list->center, VectorArrayGet(centers, i), centers->itemsize);
+		memcpy(&list->center, VectorArrayGet(centers, i), VARSIZE_ANY(VectorArrayGet(centers, i)));
 
 		/* Ensure free space */
 		if (PageGetFreeSpace(page) < listSize)
diff --git a/src/ivfflat.h b/src/ivfflat.h
index 3b918cf..bdce324 100644
--- a/src/ivfflat.h
+++ b/src/ivfflat.h
@@ -273,7 +273,7 @@ typedef IvfflatScanOpaqueData * IvfflatScanOpaque;
 #define VECTOR_ARRAY_SIZE(_length, _size) (sizeof(VectorArrayData) + (_length) * MAXALIGN(_size))
 #define VECTOR_ARRAY_OFFSET(_arr, _offset) ((char*) (_arr)->items + (_offset) * (_arr)->itemsize)
 #define VectorArrayGet(_arr, _offset) VECTOR_ARRAY_OFFSET(_arr, _offset)
-#define VectorArraySet(_arr, _offset, _val) memcpy(VECTOR_ARRAY_OFFSET(_arr, _offset), _val, (_arr)->itemsize)
+#define VectorArraySet(_arr, _offset, _val) memcpy(VECTOR_ARRAY_OFFSET(_arr, _offset), _val, VARSIZE_ANY(_val))
 
 /* Methods */
 VectorArray VectorArrayInit(int maxlen, int dimensions, Size itemsize);