diff --git a/src/hnswbuild.c b/src/hnswbuild.c
index 5d5b397..1e3e766 100644
--- a/src/hnswbuild.c
+++ b/src/hnswbuild.c
@@ -254,17 +254,14 @@ CreateNeighborPages(HnswBuildState * buildstate)
 	int			m = buildstate->m;
 	HnswElementPtr iter = buildstate->graph->head;
 	char	   *base = buildstate->hnswarea;
-	HnswNeighborTuple ntup;
-
-	/* Allocate once */
-	ntup = palloc0(BLCKSZ);
 
 	while (!HnswPtrIsNull(base, iter))
 	{
 		HnswElement e = HnswPtrAccess(base, iter);
 		Buffer		buf;
 		Page		page;
-		Size		ntupSize = HNSW_NEIGHBOR_TUPLE_SIZE(e->level, m);
+		ItemId		itemid;
+		HnswNeighborTuple ntup;
 
 		/* Update iterator */
 		iter = e->next;
@@ -276,18 +273,19 @@ CreateNeighborPages(HnswBuildState * buildstate)
 		buf = ReadBufferExtended(index, forkNum, e->neighborPage, RBM_NORMAL, NULL);
 		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 		page = BufferGetPage(buf);
+		itemid = PageGetItemId(page, e->neighborOffno);
+		ntup = (HnswNeighborTuple) PageGetItem(page, itemid);
 
+		/* Check expected size */
+		Assert(ItemIdGetLength(itemid) == HNSW_NEIGHBOR_TUPLE_SIZE(e->level, m));
+
+		/* Update page in-place */
 		HnswSetNeighborTuple(base, ntup, e, m);
 
-		if (!PageIndexTupleOverwrite(page, e->neighborOffno, (Item) ntup, ntupSize))
-			elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
-
 		/* Commit */
 		MarkBufferDirty(buf);
 		UnlockReleaseBuffer(buf);
 	}
-
-	pfree(ntup);
 }
 
 /*