From 16cc50200adfe82e52ca2d44078af248a4879d8a Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Fri, 17 Jul 2026 21:10:33 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Optimize=20ArtifactStore=20?=
 =?UTF-8?q?GC?=
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- Replace sequential fs.stat and fs.rm with chunked Promise.all for I/O
- Build state-dependent removal queue sequentially
- Significantly improves garbage collection performance and avoids EMFILE limits
---
 .jules/bolt.md                        |  3 ++
 src/core/sub-agent/artifacts/store.ts | 54 +++++++++++++++++----------
 2 files changed, 37 insertions(+), 20 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 00000000..6d2a6f17
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2024-07-17 - Optimize I/O batching across files
+**Learning:** Optimizing file operations across many files requires batching concurrent `fs.stat` and `fs.rm` (e.g., `Promise.all` with chunk size of 10) to avoid EMFILE limits, while state-dependent operations (like calculating cumulative totals) must build their removal queue sequentially before concurrent execution.
+**Action:** When refactoring sequential file system operations into batched concurrent promises, always separate state calculation into a sequential pass and restrict batched promises to pure I/O effects.
diff --git a/src/core/sub-agent/artifacts/store.ts b/src/core/sub-agent/artifacts/store.ts
index 8a7aff5c..bee8ce3d 100644
--- a/src/core/sub-agent/artifacts/store.ts
+++ b/src/core/sub-agent/artifacts/store.ts
@@ -93,13 +93,22 @@ export class ArtifactStore {
     const entries = await fs.readdir(root, { withFileTypes: true }).catch(() => []);
 
     const files: Array<{ name: string; path: string; mtimeMs: number; size: number }> = [];
-    for (const entry of entries) {
-      if (!entry.isFile()) continue;
-      const filePath = path.join(root, entry.name);
-      if (!isWithinDir(root, filePath)) continue;
-      const stat = await fs.stat(filePath).catch(() => null);
-      if (!stat) continue;
-      files.push({ name: entry.name, path: filePath, mtimeMs: stat.mtimeMs, size: stat.size });
+    const validEntries = entries.filter((e) => e.isFile());
+
+    for (let i = 0; i < validEntries.length; i += 10) {
+      const chunk = validEntries.slice(i, i + 10);
+      const stats = await Promise.all(
+        chunk.map(async (entry) => {
+          const filePath = path.join(root, entry.name);
+          if (!isWithinDir(root, filePath)) return null;
+          const stat = await fs.stat(filePath).catch(() => null);
+          if (!stat) return null;
+          return { name: entry.name, path: filePath, mtimeMs: stat.mtimeMs, size: stat.size };
+        }),
+      );
+      for (const s of stats) {
+        if (s) files.push(s);
+      }
     }
 
     const maxAgeMs = options?.maxAgeMs ?? LIMITS.artifactTtlMs;
@@ -109,18 +118,7 @@ export class ArtifactStore {
     const nowMs = Date.now();
     const expired = files.filter((f) => nowMs - f.mtimeMs > maxAgeMs);
 
-    let removedFiles = 0;
-    let removedBytes = 0;
-
-    const removeFile = async (file: { path: string; size: number }) => {
-      await fs.rm(file.path, { force: true }).catch(() => null);
-      removedFiles += 1;
-      removedBytes += file.size;
-    };
-
-    for (const file of expired) {
-      await removeFile(file);
-    }
+    const toRemove: Array<{ path: string; size: number }> = [...expired];
 
     // Recompute remaining after TTL removal (newest first).
     const remaining = files
@@ -136,11 +134,27 @@ export class ArtifactStore {
       if (!tooManyFiles && !tooManyBytes) break;
 
       const oldest = remaining[i];
-      await removeFile(oldest);
+      toRemove.push(oldest);
       currentFiles -= 1;
       currentBytes -= oldest.size;
     }
 
+    let removedFiles = 0;
+    let removedBytes = 0;
+
+    // Process removal queue in chunks concurrently
+    for (let i = 0; i < toRemove.length; i += 10) {
+      const chunk = toRemove.slice(i, i + 10);
+      await Promise.all(
+        chunk.map(async (file) => {
+          await fs.rm(file.path, { force: true }).catch(() => null);
+          // Counters updated synchronously post-operation since Promise.all guarantees completion
+          removedFiles += 1;
+          removedBytes += file.size;
+        }),
+      );
+    }
+
     return { removedFiles, removedBytes };
   }