diff --git a/src/box/tree_index.cc b/src/box/tree_index.cc
index bdb69e6b60cbbad744fe40e3ed2d16b288af31f1..b5a4df66eb8323a8c93f5e40cfe8961bd449e079 100644
--- a/src/box/tree_index.cc
+++ b/src/box/tree_index.cc
@@ -377,7 +377,7 @@ void
 TreeIndex::buildNext(struct tuple *tuple)
 {
 	if (tree.size == tree.max_size) {
-		tree.max_size *= 2;
+		tree.max_size = MAX(tree.max_size * 2, 64);
 
 		size_t sz = tree.max_size * sizeof(struct sptree_index_node);
 		tree.members = realloc(tree.members, sz);