fix(powersync): use read lock for BucketStorage.select()

BucketStorage.select() is documented for read statements only, but called
_internalDb.execute(), which acquires a write lock. All callers run SELECTs,
so route them through getAll() to take a read lock instead. This avoids
serializing read-only queries behind the write lock (e.g. on web with
SqliteConnectionPool).

Closes #384

Author: rumitvn

packages/powersync/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.3.1 (unreleased)
+
+- Fix `BucketStorage.select()` acquiring a write lock for read-only queries by using `getAll()` instead of `execute()`.
+
 ## 2.3.0
 
 - Add `SyncOptions.httpClient` to `SyncOptions`. It can be set to make PowerSync use a custom HTTP client when connecting to the PowerSync Service.

packages/powersync/lib/src/sync/bucket_storage.dart

@@ -18,7 +18,7 @@ class BucketStorage {
   // Use only for read statements
   Future<ResultSet> select(String query,
       [List<Object?> parameters = const []]) async {
-    return await _internalDb.execute(query, parameters);
+    return await _internalDb.getAll(query, parameters);
   }
 
   Future<String> getClientId() async {