fs: improve fsPromises writeFile performance

Increase the write chunk size in fsPromises writeFile to improve performance. PR-URL: #37610 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Darshan Sen <raisinten@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
nodejs · MoritzLoewenstein · Mar 5, 2021 · Sep 7, 2021 · 9a5e60b38760932d059921fcdb528e39ea9dfc9f
commit 9a5e60b38760932d059921fcdb528e39ea9dfc9f
diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
@@ -1,7 +1,5 @@
 'use strict';
 
-const kWriteFileMaxChunkSize = 2 ** 14;
-
 const {
   ArrayPrototypePush,
   Error,
@@ -40,6 +38,7 @@ const {
     kMaxUserId,
     kReadFileBufferLength,
     kReadFileUnknownBufferLength,
+    kWriteFileMaxChunkSize,
   },
   copyObject,
   getDirents,

diff --git a/lib/internal/fs/utils.js b/lib/internal/fs/utils.js
@@ -126,6 +126,8 @@ const kIoMaxLength = 2 ** 31 - 1;
 const kReadFileUnknownBufferLength = 64 * 1024;
 const kReadFileBufferLength = 512 * 1024;
 
+const kWriteFileMaxChunkSize = 512 * 1024;
+
 const kMaxUserId = 2 ** 32 - 1;
 
 const isWindows = process.platform === 'win32';
@@ -835,6 +837,7 @@ module.exports = {
     kMaxUserId,
     kReadFileBufferLength,
     kReadFileUnknownBufferLength,
+    kWriteFileMaxChunkSize,
   },
   assertEncoding,
   BigIntStats,  // for testing

diff --git a/test/parallel/test-fs-promises-file-handle-writeFile.js b/test/parallel/test-fs-promises-file-handle-writeFile.js
@@ -34,13 +34,17 @@ async function validateWriteFile() {
 async function doWriteAndCancel() {
   const filePathForHandle = path.resolve(tmpDir, 'dogs-running.txt');
   const fileHandle = await open(filePathForHandle, 'w+');
-  const buffer = Buffer.from('dogs running'.repeat(10000), 'utf8');
-  const controller = new AbortController();
-  const { signal } = controller;
-  process.nextTick(() => controller.abort());
-  await assert.rejects(writeFile(fileHandle, buffer, { signal }), {
-    name: 'AbortError'
-  });
+  try {
+    const buffer = Buffer.from('dogs running'.repeat(512 * 1024), 'utf8');
+    const controller = new AbortController();
+    const { signal } = controller;
+    process.nextTick(() => controller.abort());
+    await assert.rejects(writeFile(fileHandle, buffer, { signal }), {
+      name: 'AbortError'
+    });
+  } finally {
+    await fileHandle.close();
+  }
 }
 
 const dest = path.resolve(tmpDir, 'tmp.txt');