Major performance refactor with a few breaking changes

- Change how tables and primary keys are fetched to minimize reads
- Allow for more efficient bulk writing using Sqlite batches
- Rework abstractions to expose the Sqlite batch API
- Rename classes to better reflect their goals
- Correctly identify and forbid semicolon separated statements

CHANGELOG.md

@@ -1,3 +1,13 @@
+## 3.0.0
+
+Major performance refactor with a few breaking changes
+
+- Change how tables and primary keys are fetched to minimize reads
+- Allow for more efficient bulk writing using Sqlite batches
+- Rework abstractions to expose the Sqlite batch API
+- Rename classes to better reflect their goals
+- Correctly identify and forbid semicolon separated statements
+
 ## 2.1.7
 
 - Add support for inserts from select queries

lib/sqlite_crdt.dart

@@ -9,6 +9,7 @@ import 'package:sqflite_common_ffi_web/sqflite_ffi_web.dart';
 import 'package:sql_crdt/sql_crdt.dart';
 import 'package:sqlite_crdt/src/sqlite_api.dart';
 
+import 'src/batch_executor.dart';
 import 'src/is_web_locator.dart';
 
 export 'package:sqflite_common/sqlite_api.dart';
@@ -17,7 +18,7 @@ export 'package:sql_crdt/sql_crdt.dart';
 class SqliteCrdt extends SqlCrdt {
   final Database _db;
 
-  SqliteCrdt._(this._db) : super(SqliteApi(_db));
+  SqliteCrdt._(this._db) : super(ExecutorApi(_db));
 
   /// Open or create a SQLite container as a SqlCrdt instance.
   ///
@@ -27,8 +28,8 @@ class SqliteCrdt extends SqlCrdt {
     String path, {
     bool singleInstance = true,
     int? version,
-    FutureOr<void> Function(BaseCrdt crdt, int version)? onCreate,
-    FutureOr<void> Function(BaseCrdt crdt, int from, int to)? onUpgrade,
+    FutureOr<void> Function(Database db, int version)? onCreate,
+    FutureOr<void> Function(Database db, int from, int to)? onUpgrade,
   }) =>
       _open(path, false, singleInstance, version, onCreate, onUpgrade);
 
@@ -37,20 +38,31 @@ class SqliteCrdt extends SqlCrdt {
   static Future<SqliteCrdt> openInMemory({
     bool singleInstance = false,
     int? version,
-    FutureOr<void> Function(BaseCrdt crdt, int version)? onCreate,
-    FutureOr<void> Function(BaseCrdt crdt, int from, int to)? onUpgrade,
+    FutureOr<void> Function(CrdtTableExecutor db, int version)? onCreate,
+    FutureOr<void> Function(CrdtTableExecutor db, int from, int to)? onUpgrade,
   }) =>
-      _open(null, true, singleInstance, version, onCreate, onUpgrade);
-
-  Future<void> close() => _db.close();
+      _open(
+        null,
+        true,
+        singleInstance,
+        version,
+        onCreate == null
+            ? null
+            : (db, version) =>
+                onCreate(CrdtTableExecutor(ExecutorApi(db)), version),
+        onUpgrade == null
+            ? null
+            : (db, from, to) =>
+                onUpgrade(CrdtTableExecutor(ExecutorApi(db)), from, to),
+      );
 
   static Future<SqliteCrdt> _open(
     String? path,
     bool inMemory,
     bool singleInstance,
     int? version,
-    FutureOr<void> Function(BaseCrdt crdt, int version)? onCreate,
-    FutureOr<void> Function(BaseCrdt crdt, int from, int to)? onUpgrade,
+    FutureOr<void> Function(Database db, int version)? onCreate,
+    FutureOr<void> Function(Database db, int from, int to)? onUpgrade,
   ) async {
     if (sqliteCrdtIsWeb && !inMemory && path!.contains('/')) {
       path = path.substring(path.lastIndexOf('/') + 1);
@@ -68,18 +80,31 @@ class SqliteCrdt extends SqlCrdt {
       options: SqfliteOpenDatabaseOptions(
         singleInstance: singleInstance,
         version: version,
-        onCreate: onCreate == null
-            ? null
-            : (db, version) => onCreate.call(BaseCrdt(SqliteApi(db)), version),
-        onUpgrade: onUpgrade == null
-            ? null
-            : (db, from, to) =>
-                onUpgrade.call(BaseCrdt(SqliteApi(db)), from, to),
+        onCreate: onCreate,
+        onUpgrade: onUpgrade,
       ),
     );
 
     final crdt = SqliteCrdt._(db);
     await crdt.init();
     return crdt;
   }
+
+  Future<void> close() => _db.close();
+
+  @override
+  Future<Iterable<String>> getTables() async => (await _db.rawQuery('''
+        SELECT name FROM sqlite_schema
+        WHERE type ='table' AND name NOT LIKE 'sqlite_%'
+      ''')).map((e) => e['name'] as String);
+
+  @override
+  Future<Iterable<String>> getTableKeys(String table) async =>
+      (await _db.rawQuery('''
+         SELECT name FROM pragma_table_info(?1)
+         WHERE pk > 0
+       ''', [table])).map((e) => e['name'] as String);
+
+  BatchExecutor batch() =>
+      BatchExecutor(_db.batch(), canonicalTime.increment());
 }

lib/src/batch_executor.dart

@@ -0,0 +1,17 @@
+import 'package:sqflite_common/sqlite_api.dart';
+import 'package:sql_crdt/sql_crdt.dart';
+import 'package:sqlite_crdt/src/sqlite_api.dart';
+
+/// Wrapper around Sqlite batches that automatically applies CRDT metadata to
+/// inserted records.
+///
+/// Note that timestamps are fixed at the moment of instantiation, so creating
+/// long-lived batches is discouraged.
+class BatchExecutor extends CrdtExecutor {
+  final Batch _batch;
+
+  BatchExecutor(this._batch, Hlc hlc) : super(BatchApi(_batch), hlc);
+
+  /// Commit this batch atomically. See Sqlite documentation for details.
+  Future<List<Object?>> commit() => _batch.commit();
+}

lib/src/sqlite_api.dart

@@ -1,23 +1,12 @@
+import 'dart:async';
+
 import 'package:sqflite_common/sqlite_api.dart';
 import 'package:sql_crdt/sql_crdt.dart';
 
-class SqliteApi extends DatabaseApi {
+class ExecutorApi extends DatabaseApi {
   final DatabaseExecutor _db;
 
-  SqliteApi(this._db);
-
-  @override
-  Future<Iterable<String>> getTables() async => (await _db.rawQuery('''
-        SELECT name FROM sqlite_schema
-        WHERE type ='table' AND name NOT LIKE 'sqlite_%'
-      ''')).map((e) => e['name'] as String);
-
-  @override
-  Future<Iterable<String>> getPrimaryKeys(String table) async =>
-      (await _db.rawQuery('''
-         SELECT name FROM pragma_table_info(?1)
-         WHERE pk > 0
-       ''', [table])).map((e) => e['name'] as String);
+  ExecutorApi(this._db);
 
   @override
   Future<void> execute(String sql, [List<Object?>? args]) =>
@@ -28,9 +17,28 @@ class SqliteApi extends DatabaseApi {
       _db.rawQuery(sql, args);
 
   @override
-  Future<void> transaction(
-      Future<void> Function(DatabaseApi txn) action) async {
+  Future<void> transaction(Future<void> Function(ReadWriteApi api) actions) {
     assert(_db is Database, 'Cannot start a transaction within a transaction');
-    return (_db as Database).transaction((t) => action(SqliteApi(t)));
+    return (_db as Database).transaction((t) => actions(ExecutorApi(t)));
+  }
+
+  @override
+  Future<void> executeBatch(
+      FutureOr<void> Function(WriteApi api) actions) async {
+    final batch = _db.batch();
+    actions(BatchApi(batch));
+    await batch.commit();
   }
 }
+
+/// Simplified wrapper intended for Sqlite batches.
+class BatchApi extends WriteApi {
+  final Batch _batch;
+
+  BatchApi(this._batch);
+
+  void query(String sql, [List<Object?>? args]) => _batch.rawQuery(sql, args);
+
+  @override
+  void execute(String sql, [List<Object?>? args]) => _batch.execute(sql, args);
+}

pubspec.yaml

@@ -1,6 +1,6 @@
 name: sqlite_crdt
 description: Dart implementation of Conflict-free Replicated Data Types (CRDTs) using Sqlite
-version: 2.1.7
+version: 3.0.0
 homepage: https://github.com/cachapa/sqlite_crdt
 repository: https://github.com/cachapa/sqlite_crdt
 issue_tracker: https://github.com/cachapa/sqlite_crdt/issues
@@ -12,7 +12,7 @@ dependencies:
   sqflite_common: ^2.5.3
   sqflite_common_ffi: ^2.3.2+1
   sqflite_common_ffi_web: ^0.4.2+3
-  sql_crdt: ^2.1.7
+  sql_crdt: ^3.0.0
 #    path: ../sql_crdt
 
 dev_dependencies: