diff --git a/src/key_value_store/kv_flat_btree_async.cc b/src/key_value_store/kv_flat_btree_async.cc
index 663fcde44dbf8..77d11b0951ca5 100644
--- a/src/key_value_store/kv_flat_btree_async.cc
+++ b/src/key_value_store/kv_flat_btree_async.cc
@@ -2169,6 +2169,7 @@ string KvFlatBtreeAsync::str() {
   io_ctx.aio_operate(index_name, top_aioc, &oro, NULL);
   top_aioc->wait_for_safe();
   err = top_aioc->get_return_value();
+  top_aioc->release();
   if (err < 0 && err != -5){
     if (verbose) cout << "getting keys failed with error " << err << std::endl;
     return ret.str();