perf: SQLite WAL + 复合索引 + GZip + scheduler jitter + 构建缓存

backend/app/database.py

@@ -1,4 +1,4 @@
-from sqlalchemy import create_engine, inspect, text
+from sqlalchemy import create_engine, event, inspect, text
 from sqlalchemy.orm import sessionmaker, DeclarativeBase
 from app.config import get_settings
 
@@ -8,6 +8,21 @@ engine = create_engine(
     settings.database_url,
     connect_args={"check_same_thread": False},
 )
+
+# ── SQLite 性能 PRAGMA（WAL + 缓存 + 超时） ──
+@event.listens_for(engine, "connect", insert=True)
+def _set_sqlite_pragma(dbapi_connection, connection_record):
+    if engine.dialect.name != "sqlite":
+        return
+    cursor = dbapi_connection.cursor()
+    cursor.execute("PRAGMA journal_mode=WAL;")
+    cursor.execute("PRAGMA synchronous=NORMAL;")
+    cursor.execute("PRAGMA busy_timeout=5000;")
+    cursor.execute("PRAGMA foreign_keys=ON;")
+    cursor.execute("PRAGMA cache_size=-20000;")        # 20 MB page cache
+    cursor.execute("PRAGMA mmap_size=67108864;")        # 64 MB（小内存容器友好）
+    cursor.close()
+
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
 
 
@@ -28,11 +43,35 @@ def init_db():
     # import models so SQLAlchemy registers them
     from app.models import admin_user, upstream, snapshot, webhook_config, notification_log, custom_page, website, revoked_token, upstream_key  # noqa: F401
     Base.metadata.create_all(bind=engine)
+    _ensure_indexes()
     _migrate_custom_pages()
     _migrate_upstreams()
     _migrate_upstream_generated_keys()
 
 
+# ── 已有数据库幂等索引迁移 ─────────────────────────────────
+_NEW_INDEXES = [
+    "CREATE INDEX IF NOT EXISTS ix_snapshot_upstream_captured ON upstream_rate_snapshots(upstream_id, captured_at DESC)",
+    "CREATE INDEX IF NOT EXISTS ix_notif_event_created ON notification_logs(event_type, created_at DESC)",
+    "CREATE INDEX IF NOT EXISTS ix_notif_status_created ON notification_logs(status, created_at DESC)",
+    "CREATE INDEX IF NOT EXISTS ix_sync_website_created ON website_sync_logs(website_id, created_at DESC)",
+    "CREATE INDEX IF NOT EXISTS ix_sync_binding_created ON website_sync_logs(binding_id, created_at DESC)",
+    "CREATE INDEX IF NOT EXISTS ix_upstream_enabled ON upstreams(enabled)",
+    "CREATE INDEX IF NOT EXISTS ix_key_upstream_name ON upstream_generated_keys(upstream_id, key_name)",
+]
+
+
+def _ensure_indexes() -> None:
+    """创建 InitDB 时可能未包含的复合索引，幂等执行。"""
+    with engine.begin() as conn:
+        for stmt in _NEW_INDEXES:
+            try:
+                conn.execute(text(stmt))
+            except Exception:
+                logger = __import__("logging").getLogger(__name__)
+                logger.warning("index creation failed (non-fatal): %s", stmt[:60])
+
+
 def _migrate_custom_pages():
     """Apply small SQLite-safe migrations for deployments without Alembic."""
     inspector = inspect(engine)