diff --git a/src/ivfflat.h b/src/ivfflat.h
index 32b184a..13c3425 100644
--- a/src/ivfflat.h
+++ b/src/ivfflat.h
@@ -83,7 +83,7 @@ typedef struct VectorArrayData
 	int			length;
 	int			maxlen;
 	int			dim;
-	Vector		items[FLEXIBLE_ARRAY_MEMBER];
+	Vector	   *items;
 }			VectorArrayData;
 
 typedef VectorArrayData * VectorArray;
@@ -204,8 +204,8 @@ typedef struct IvfflatScanOpaqueData
 
 typedef IvfflatScanOpaqueData * IvfflatScanOpaque;
 
-#define VECTOR_ARRAY_SIZE(_length, _dim) (offsetof(VectorArrayData, items) + _length * VECTOR_SIZE(_dim))
-#define VECTOR_ARRAY_OFFSET(_arr, _offset) ((char*) _arr + offsetof(VectorArrayData, items) + (_offset) * VECTOR_SIZE(_arr->dim))
+#define VECTOR_ARRAY_SIZE(_length, _dim) (sizeof(VectorArrayData) + (_length) * VECTOR_SIZE(_dim))
+#define VECTOR_ARRAY_OFFSET(_arr, _offset) ((char*) _arr->items + (_offset) * VECTOR_SIZE(_arr->dim))
 #define VectorArrayGet(_arr, _offset) ((Vector *) VECTOR_ARRAY_OFFSET(_arr, _offset))
 #define VectorArraySet(_arr, _offset, _val) (memcpy(VECTOR_ARRAY_OFFSET(_arr, _offset), _val, VECTOR_SIZE(_arr->dim)))
 
diff --git a/src/ivfutils.c b/src/ivfutils.c
index 2b5bb7d..b3caec8 100644
--- a/src/ivfutils.c
+++ b/src/ivfutils.c
@@ -10,11 +10,12 @@
 VectorArray
 VectorArrayInit(int maxlen, int dimensions)
 {
-	VectorArray res = palloc_extended(VECTOR_ARRAY_SIZE(maxlen, dimensions), MCXT_ALLOC_ZERO | MCXT_ALLOC_HUGE);
+	VectorArray res = palloc(sizeof(VectorArrayData));
 
 	res->length = 0;
 	res->maxlen = maxlen;
 	res->dim = dimensions;
+	res->items = palloc_extended(maxlen * VECTOR_SIZE(dimensions), MCXT_ALLOC_ZERO | MCXT_ALLOC_HUGE);
 	return res;
 }
 
@@ -24,6 +25,7 @@ VectorArrayInit(int maxlen, int dimensions)
 void
 VectorArrayFree(VectorArray arr)
 {
+	pfree(arr->items);
 	pfree(arr);
 }