[Node.js] Prevent database is locked errors (#749)

Author: stevensJourney

.changeset/friendly-queens-invite.md

@@ -0,0 +1,5 @@
+---
+'@powersync/node': patch
+---
+
+[`node:sqlite`] Prevent `database is locked` errors when instantiating the database.

packages/node/src/db/WorkerConnectionPool.ts

@@ -1,24 +1,24 @@
+import * as Comlink from 'comlink';
 import fs from 'node:fs/promises';
 import * as path from 'node:path';
 import { Worker } from 'node:worker_threads';
-import * as Comlink from 'comlink';
 
 import {
   BaseObserver,
   BatchedUpdateNotification,
   DBAdapter,
   DBAdapterListener,
-  LockContext,
-  Transaction,
   DBLockOptions,
-  QueryResult
+  LockContext,
+  QueryResult,
+  Transaction
 } from '@powersync/common';
 import { Remote } from 'comlink';
 import { AsyncResource } from 'node:async_hooks';
+import { isBundledToCommonJs } from '../utils/modules.js';
 import { AsyncDatabase, AsyncDatabaseOpener } from './AsyncDatabase.js';
 import { RemoteConnection } from './RemoteConnection.js';
 import { NodeDatabaseImplementation, NodeSQLOpenOptions } from './options.js';
-import { isBundledToCommonJs } from '../utils/modules.js';
 
 export type BetterSQLite3LockContext = LockContext & {
   executeBatch(query: string, params?: any[][]): Promise<QueryResult>;
@@ -135,10 +135,12 @@ export class WorkerConnectionPool extends BaseObserver<DBAdapterListener> implem
       if (this.options.initializeConnection) {
         await this.options.initializeConnection(connection, isWriter);
       }
-
-      await connection.execute('pragma journal_mode = WAL');
       if (!isWriter) {
         await connection.execute('pragma query_only = true');
+      } else {
+        // We only need to enable this on the writer connection.
+        // We can get `database is locked` errors if we enable this on concurrently opening read connections.
+        await connection.execute('pragma journal_mode = WAL');
       }
 
       return connection;

packages/node/tests/PowerSyncDatabase.test.ts

@@ -1,11 +1,12 @@
 import * as path from 'node:path';
 import { Worker } from 'node:worker_threads';
 
-import { vi, expect, test } from 'vitest';
-import { AppSchema, databaseTest, tempDirectoryTest } from './utils';
+import { LockContext } from '@powersync/common';
+import { randomUUID } from 'node:crypto';
+import { expect, test, vi } from 'vitest';
 import { CrudEntry, CrudTransaction, PowerSyncDatabase } from '../lib';
 import { WorkerOpener } from '../lib/db/options';
-import { LockContext } from '@powersync/common';
+import { AppSchema, databaseTest, tempDirectoryTest } from './utils';
 
 test('validates options', async () => {
   await expect(async () => {
@@ -203,3 +204,26 @@ databaseTest('getCrudTransactions', async ({ database }) => {
   const remainingTransaction = await database.getNextCrudTransaction();
   expect(remainingTransaction?.crud).toHaveLength(15);
 });
+
+// This is not a SemVer check, but is basic enough to skip this test on older versions of Node.js
+tempDirectoryTest.skipIf(process.versions.node < '22.5.0')(
+  'should not present database is locked errors on startup',
+  async ({ tmpdir }) => {
+    for (let i = 0; i < 10; i++) {
+      const database = new PowerSyncDatabase({
+        schema: AppSchema,
+        database: {
+          dbFilename: `${randomUUID()}.sqlite`,
+          dbLocation: tmpdir,
+          implementation: {
+            type: 'node:sqlite'
+          }
+        }
+      });
+
+      // This should not throw
+      await database.waitForReady();
+      await database.close();
+    }
+  }
+);

pnpm-workspace.yaml

@@ -3,3 +3,7 @@ packages:
   - packages/*
   - tools/*
   - docs/
+
+onlyBuiltDependencies:
+  - better-sqlite3
+  - better-sqlite3-multiple-ciphers