Heapgraph Stats

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

General statistics on the heap graph

namespace HH;

function heapgraph_stats(
  resource $heapgraph,
): darray<string, int>;

Parameters

• resource $heapgraph - The resource obtained with heapgraph_create

Returns

• array<string, - int> - General metrics describing the heap graph. Keys are defined as follows:

nodes count of nodes in the graph edges count of pointers (edges) in the graph roots count of root->nonroot pointers (pointers where from is root) root_nodes count of root nodes exact 1 if type scanners were built, 0 otherwise