perf(redis): pipeline TYPE/TTL for SCAN batches (#426)

lib/core/database/redis_connection.dart

@@ -206,6 +206,45 @@ class RedisConnection {
     return result is int ? result : int.tryParse(result.toString()) ?? -1;
   }
 
+  /// Pipelined TYPE + TTL for a SCAN batch.
+  ///
+  /// Writes all commands before awaiting replies (redis-dart FIFO parse
+  /// queue + optional Nagle via [Command.pipe_start]), so a batch of N keys
+  /// costs ~1 RTT instead of ~2N sequential round-trips.
+  Future<List<({String type, int ttl})>> typesAndTtls(List<String> keys) async {
+    if (keys.isEmpty) return const [];
+    if (!isConnected) {
+      throw StateError('Not connected to Redis');
+    }
+
+    final cmd = _command;
+    cmd?.pipe_start();
+    try {
+      final typeFutures = <Future<String>>[
+        for (final key in keys)
+          sendCommand(['TYPE', key]).then(
+            (v) => v?.toString() ?? 'none',
+            onError: (_) => 'unknown',
+          ),
+      ];
+      final ttlFutures = <Future<int>>[
+        for (final key in keys)
+          sendCommand(['TTL', key]).then(
+            (v) => v is int ? v : int.tryParse(v.toString()) ?? -1,
+            onError: (_) => -1,
+          ),
+      ];
+      final types = await Future.wait(typeFutures);
+      final ttls = await Future.wait(ttlFutures);
+      return [
+        for (var i = 0; i < keys.length; i++)
+          (type: types[i], ttl: ttls[i]),
+      ];
+    } finally {
+      cmd?.pipe_end();
+    }
+  }
+
   /// GET (string).
   Future<String?> get(String key) async {
     final result = await sendCommand(['GET', key]);

lib/features/redis/redis_keys_view.dart

@@ -78,17 +78,24 @@ class _RedisKeysViewState extends material.State<RedisKeysView> {
       count: 100,
     );
 
-    // Fetch type and TTL for each key concurrently
-    final futures = keyNames.map((name) async {
-      try {
-        final type = await widget.connection.keyType(name);
-        final ttl = await widget.connection.ttl(name);
-        return _KeyInfo(name: name, type: type, ttl: ttl);
-      } catch (_) {
-        return _KeyInfo(name: name, type: 'unknown', ttl: -1);
-      }
-    });
-    final infos = await Future.wait(futures);
+    // One pipelined burst of TYPE+TTL (not N× Future.wait round-trips).
+    List<_KeyInfo> infos;
+    try {
+      final metas = await widget.connection.typesAndTtls(keyNames);
+      infos = [
+        for (var i = 0; i < keyNames.length; i++)
+          _KeyInfo(
+            name: keyNames[i],
+            type: metas[i].type,
+            ttl: metas[i].ttl,
+          ),
+      ];
+    } catch (_) {
+      infos = [
+        for (final name in keyNames)
+          _KeyInfo(name: name, type: 'unknown', ttl: -1),
+      ];
+    }
 
     if (!mounted) return;
     setState(() {

test/core/database/redis_types_and_ttls_test.dart

@@ -0,0 +1,43 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/core/database/redis_connection.dart';
+
+/// Counts outbound commands to prove [typesAndTtls] fires TYPE+TTL without
+/// awaiting between keys (true pipeline enqueue).
+class _CountingRedisFake extends RedisConnectionTestFake {
+  _CountingRedisFake() : super(firstScanKeys: const []);
+
+  final List<String> ops = [];
+
+  @override
+  Future<dynamic> sendCommand(List<dynamic> args) async {
+    ops.add(args.first.toString().toUpperCase());
+    // Delay so overlapping awaits would change order if callers awaited per key.
+    await Future<void>.delayed(Duration.zero);
+    return super.sendCommand(args);
+  }
+}
+
+void main() {
+  test('typesAndTtls enqueues all TYPE then all TTL before settling', () async {
+    final fake = _CountingRedisFake();
+    await fake.connect();
+
+    final metas = await fake.typesAndTtls(['a', 'b', 'c']);
+
+    expect(metas, hasLength(3));
+    expect(metas.map((m) => m.type), everyElement('string'));
+    expect(metas.map((m) => m.ttl), everyElement(-1));
+
+    // All TYPE writes precede all TTL writes (single burst, not TYPE+TTL per key).
+    expect(
+      fake.ops,
+      ['TYPE', 'TYPE', 'TYPE', 'TTL', 'TTL', 'TTL'],
+    );
+  });
+
+  test('typesAndTtls returns empty for empty keys', () async {
+    final fake = RedisConnectionTestFake();
+    await fake.connect();
+    expect(await fake.typesAndTtls(const []), isEmpty);
+  });
+}