From bbfcdf21e507b91968f9fc72746e9fce2941a687 Mon Sep 17 00:00:00 2001
From: Leonardo Venturini <leovenbag@gmail.com>
Date: Wed, 16 Oct 2024 08:05:46 -0400
Subject: [PATCH] add garbage collection to async resource map

---
 async-interceptor.js | 30 ++++++++++++++++++++++--------
 save-output.js       |  4 ++--
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/async-interceptor.js b/async-interceptor.js
index 8f210ab..646ae87 100644
--- a/async-interceptor.js
+++ b/async-interceptor.js
@@ -1,25 +1,39 @@
 import async_hooks from 'node:async_hooks';
 
-export const asyncResources = new Map();
+// 50% of map limit
+export const GC_LIMIT = Math.pow(2, 23);
+
+export const AsyncResourceMap = new Map();
 
 export const AsyncInterceptor = async_hooks.createHook({
-  init(asyncId, type, triggerAsyncId, resource) {
-    logResourceCreation(asyncId, type, triggerAsyncId, resource);
+  init(asyncId, type) {
+    logResourceCreation(asyncId, type);
   },
 });
 
-function logResourceCreation(asyncId, type, triggerAsyncId, resource) {
+function logResourceCreation(asyncId, type) {
   const stack = (new Error()).stack.split('\n').slice(2).filter(line => {
     return !['AsyncHook.init', 'node:internal/async_hooks'].some(fn => line.includes(fn));
   }).join('\n');
 
-  if (!asyncResources.has(stack)) {
-    asyncResources.set(stack, { count: 0, types: new Set() });
+  if (AsyncResourceMap.size > GC_LIMIT) {
+    console.log('Meteor Perf: Garbage collecting async resources');
+    garbageCollectAsyncResources();
+  }
+
+  if (!AsyncResourceMap.has(stack)) {
+    AsyncResourceMap.set(stack, { count: 0, types: new Set() });
   }
 
-  const resourceInfo = asyncResources.get(stack);
+  const resourceInfo = AsyncResourceMap.get(stack);
   resourceInfo.count++;
   resourceInfo.types.add(type);
 }
 
-
+function garbageCollectAsyncResources() {
+  AsyncResourceMap.forEach((info, stack) => {
+    if (info.count <= 1) {
+      AsyncResourceMap.delete(stack);
+    }
+  });
+}
\ No newline at end of file
diff --git a/save-output.js b/save-output.js
index 793319d..14a20f6 100644
--- a/save-output.js
+++ b/save-output.js
@@ -1,4 +1,4 @@
-import { asyncResources } from './async-interceptor';
+import { AsyncResourceMap } from './async-interceptor';
 import { StatDict } from './observer-monitor';
 import path from 'node:path';
 import fs from 'node:fs';
@@ -9,7 +9,7 @@ export function saveOutput() {
   performance.mark('saveOutput-start');
   let async_traces = []
 
-  asyncResources.forEach((info, stack) => {
+  AsyncResourceMap.forEach((info, stack) => {
     if (info.count <= 1) {
       return;
     }