fix: optimize DB pull (#2589)

apps/electron/layers/main/src/workers/index.ts

@@ -0,0 +1,35 @@
+import path from 'node:path';
+import { Worker } from 'node:worker_threads';
+
+import { mergeUpdate } from './merge-update';
+
+export function mergeUpdateWorker(updates: Uint8Array[]) {
+  // fallback to main thread if worker is disabled (in vitest)
+  if (process.env.USE_WORKER !== 'true') {
+    return mergeUpdate(updates);
+  }
+  return new Promise<Uint8Array>((resolve, reject) => {
+    // it is intended to have "./workers" in the path
+    const workerFile = path.join(__dirname, './workers/merge-update.worker.js');
+
+    // convert updates to SharedArrayBuffer[s]
+    const sharedArrayBufferUpdates = updates.map(update => {
+      const buffer = new SharedArrayBuffer(update.byteLength);
+      const view = new Uint8Array(buffer);
+      view.set(update);
+      return view;
+    });
+
+    const worker = new Worker(workerFile, {
+      workerData: sharedArrayBufferUpdates,
+    });
+
+    worker.on('message', resolve);
+    worker.on('error', reject);
+    worker.on('exit', code => {
+      if (code !== 0) {
+        reject(new Error(`Worker stopped with exit code ${code}`));
+      }
+    });
+  });
+}