fix(http): 支持默认HTTP客户端原子重建以恢复HTTP/2流容量

feat(db): 为外键列补充缺失的数据库索引并添加迁移脚本

- HTTPClientPool._reset_default_client 原子替换共享客户端，旧客户端在宽限期后异步关闭
- reset_upstream_client 对无代理路由不再直接跳过，改为调用 _reset_default_client
- 为 Usage, WalletTransaction, PaymentCallback, RefundRequest, VideoTask, RequestCandidate 等表的外键列添加 index=True

alembic/versions/20260307_1628_2d932114930d_add_missing_foreign_key_indexes_for_.py

@@ -0,0 +1,80 @@
+"""add missing foreign key indexes for cascade delete performance
+
+Revision ID: 2d932114930d
+Revises: 8e71f2a4c9b0
+Create Date: 2026-03-07 16:28:48.633531+00:00
+
+"""
+from alembic import op
+from sqlalchemy import inspect
+
+# revision identifiers, used by Alembic.
+revision = '2d932114930d'
+down_revision = '8e71f2a4c9b0'
+branch_labels = None
+depends_on = None
+
+
+def _index_exists(table_name: str, index_name: str) -> bool:
+    bind = op.get_bind()
+    insp = inspect(bind)
+    return any(idx["name"] == index_name for idx in insp.get_indexes(table_name))
+
+
+def _create_index_if_not_exists(index_name: str, table_name: str, columns: list[str]) -> None:
+    if not _index_exists(table_name, index_name):
+        op.create_index(op.f(index_name), table_name, columns, unique=False)
+
+
+def _drop_index_if_exists(index_name: str, table_name: str) -> None:
+    if _index_exists(table_name, index_name):
+        op.drop_index(op.f(index_name), table_name=table_name)
+
+
+# (index_name, table_name, columns)
+_INDEXES = [
+    # api_keys.user_id (CASCADE -> users.id)
+    ('ix_api_keys_user_id', 'api_keys', ['user_id']),
+    # usage: wallet_id, provider_endpoint_id, provider_api_key_id (SET NULL)
+    ('ix_usage_wallet_id', 'usage', ['wallet_id']),
+    ('ix_usage_provider_endpoint_id', 'usage', ['provider_endpoint_id']),
+    ('ix_usage_provider_api_key_id', 'usage', ['provider_api_key_id']),
+    # wallet_transactions.operator_id (SET NULL -> users.id)
+    ('ix_wallet_transactions_operator_id', 'wallet_transactions', ['operator_id']),
+    # payment_callbacks.payment_order_id (SET NULL -> payment_orders.id)
+    ('ix_payment_callbacks_payment_order_id', 'payment_callbacks', ['payment_order_id']),
+    # refund_requests: payment_order_id, requested_by, approved_by, processed_by (SET NULL)
+    ('ix_refund_requests_payment_order_id', 'refund_requests', ['payment_order_id']),
+    ('ix_refund_requests_requested_by', 'refund_requests', ['requested_by']),
+    ('ix_refund_requests_approved_by', 'refund_requests', ['approved_by']),
+    ('ix_refund_requests_processed_by', 'refund_requests', ['processed_by']),
+    # proxy_nodes.registered_by (SET NULL -> users.id)
+    ('ix_proxy_nodes_registered_by', 'proxy_nodes', ['registered_by']),
+    # video_tasks: api_key_id, provider_id, endpoint_id, key_id, remixed_from_task_id
+    ('ix_video_tasks_api_key_id', 'video_tasks', ['api_key_id']),
+    ('ix_video_tasks_provider_id', 'video_tasks', ['provider_id']),
+    ('ix_video_tasks_endpoint_id', 'video_tasks', ['endpoint_id']),
+    ('ix_video_tasks_key_id', 'video_tasks', ['key_id']),
+    ('ix_video_tasks_remixed_from_task_id', 'video_tasks', ['remixed_from_task_id']),
+    # user_preferences.default_provider_id (-> providers.id)
+    ('ix_user_preferences_default_provider_id', 'user_preferences', ['default_provider_id']),
+    # announcements.author_id (SET NULL -> users.id)
+    ('ix_announcements_author_id', 'announcements', ['author_id']),
+    # announcement_reads.announcement_id (-> announcements.id)
+    ('ix_announcement_reads_announcement_id', 'announcement_reads', ['announcement_id']),
+    # request_candidates: user_id, api_key_id, endpoint_id, key_id (CASCADE)
+    ('ix_request_candidates_user_id', 'request_candidates', ['user_id']),
+    ('ix_request_candidates_api_key_id', 'request_candidates', ['api_key_id']),
+    ('ix_request_candidates_endpoint_id', 'request_candidates', ['endpoint_id']),
+    ('ix_request_candidates_key_id', 'request_candidates', ['key_id']),
+]
+
+
+def upgrade() -> None:
+    for index_name, table_name, columns in _INDEXES:
+        _create_index_if_not_exists(index_name, table_name, columns)
+
+
+def downgrade() -> None:
+    for index_name, table_name, _columns in reversed(_INDEXES):
+        _drop_index_if_exists(index_name, table_name)

src/clients/http_client.py

@@ -54,6 +54,8 @@ class HTTPClientPool:
     _max_proxy_clients: int = 50
     # Tunnel 客户端缓存：{node_id: client}
     _tunnel_clients: dict[str, httpx.AsyncClient] = {}
+    # 后台清理任务引用集合（防止被 GC 回收）
+    _background_tasks: set[asyncio.Task[None]] = set()
 
     def __new__(cls) -> "HTTPClientPool":
         if cls._instance is None:
@@ -457,6 +459,51 @@ class HTTPClientPool:
         client_config.update(kwargs)
         return httpx.AsyncClient(**client_config)  # type: ignore[arg-type]
 
+    @classmethod
+    async def _reset_default_client(cls) -> bool:
+        """Atomically replace the shared default client with a fresh instance.
+
+        The old client is kept open briefly so that in-flight requests can
+        finish on their existing HTTP/2 streams; it is closed asynchronously
+        after a short grace period.
+        """
+        async with _default_client_lock:
+            old_client = cls._default_client
+            if old_client is None:
+                return False
+
+            # Create a new client before discarding the old one
+            cls._default_client = httpx.AsyncClient(
+                http2=config.enable_http2,
+                verify=get_ssl_context(),
+                timeout=httpx.Timeout(
+                    connect=config.http_connect_timeout,
+                    read=config.http_read_timeout,
+                    write=config.http_write_timeout,
+                    pool=config.http_pool_timeout,
+                ),
+                limits=httpx.Limits(
+                    max_connections=config.http_max_connections,
+                    max_keepalive_connections=config.http_keepalive_connections,
+                    keepalive_expiry=config.http_keepalive_expiry,
+                ),
+                follow_redirects=True,
+            )
+
+        # Close old client after a grace period so in-flight requests can drain
+        async def _close_old() -> None:
+            await asyncio.sleep(5)
+            try:
+                await old_client.aclose()
+            except Exception as exc:
+                logger.warning("关闭旧默认客户端失败: {}", exc)
+
+        task = asyncio.create_task(_close_old())
+        cls._background_tasks.add(task)
+        task.add_done_callback(cls._background_tasks.discard)
+        logger.warning("默认HTTP客户端已重建(HTTP/2 流容量恢复)")
+        return True
+
     @classmethod
     async def reset_upstream_client(
         cls,
@@ -467,8 +514,9 @@ class HTTPClientPool:
         """Reset cached upstream client for the given proxy/tunnel route.
 
         Returns True when a cached client was closed and removed.
-        For the shared no-proxy default client this is a no-op to avoid
+        For the shared no-proxy default client, atomically replaces it with a
-        disrupting unrelated in-flight requests.
+        new instance so that subsequent requests get a fresh HTTP/2 connection
+        while in-flight requests on the old client can finish naturally.
         """
         if delegate_cfg and delegate_cfg.get("tunnel"):
             node_id = str(delegate_cfg.get("node_id") or "")
@@ -490,7 +538,7 @@ class HTTPClientPool:
 
         base_cache_key = compute_proxy_cache_key(proxy_config)
         if base_cache_key == "__no_proxy__":
-            return False
+            return await cls._reset_default_client()
 
         cache_key_prefixes = [base_cache_key]
         tls_profile_key = str(tls_profile or "").strip().lower()

src/models/database.py

@@ -188,7 +188,9 @@ class ApiKey(Base):
     )
 
     id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
-    user_id = Column(String(36), ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
+    user_id = Column(
+        String(36), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
+    )
     key_hash = Column(String(64), unique=True, index=True, nullable=False)  # API密钥的SHA256哈希
     key_encrypted = Column(Text, nullable=True)  # 加密后的完整密钥，用于查看
     name = Column(String(100), nullable=True)  # 密钥名称，便于用户管理
@@ -319,7 +321,9 @@ class Usage(Base):
     id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
     user_id = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
     api_key_id = Column(String(36), ForeignKey("api_keys.id", ondelete="SET NULL"), nullable=True)
-    wallet_id = Column(String(36), ForeignKey("wallets.id", ondelete="SET NULL"), nullable=True)
+    wallet_id = Column(
+        String(36), ForeignKey("wallets.id", ondelete="SET NULL"), nullable=True, index=True
+    )
 
     # 请求信息
     request_id = Column(String(100), unique=True, index=True, nullable=False)
@@ -332,10 +336,16 @@ class Usage(Base):
     # Provider 侧追踪信息（记录最终成功的 Provider/Endpoint/Key）
     provider_id = Column(String(36), ForeignKey("providers.id", ondelete="SET NULL"), nullable=True)
     provider_endpoint_id = Column(
-        String(36), ForeignKey("provider_endpoints.id", ondelete="SET NULL"), nullable=True
+        String(36),
+        ForeignKey("provider_endpoints.id", ondelete="SET NULL"),
+        nullable=True,
+        index=True,
     )
     provider_api_key_id = Column(
-        String(36), ForeignKey("provider_api_keys.id", ondelete="SET NULL"), nullable=True
+        String(36),
+        ForeignKey("provider_api_keys.id", ondelete="SET NULL"),
+        nullable=True,
+        index=True,
     )
 
     # Token统计
@@ -582,7 +592,9 @@ class WalletTransaction(Base):
 
     link_type = Column(String(30), nullable=True)
     link_id = Column(String(100), nullable=True)
-    operator_id = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
+    operator_id = Column(
+        String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
+    )
     description = Column(Text, nullable=True)
 
     created_at = Column(
@@ -648,7 +660,7 @@ class PaymentCallback(Base):
 
     id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
     payment_order_id = Column(
-        String(36), ForeignKey("payment_orders.id", ondelete="SET NULL"), nullable=True
+        String(36), ForeignKey("payment_orders.id", ondelete="SET NULL"), nullable=True, index=True
     )
     payment_method = Column(String(30), nullable=False)
 
@@ -686,7 +698,7 @@ class RefundRequest(Base):
     wallet_id = Column(String(36), ForeignKey("wallets.id", ondelete="RESTRICT"), nullable=False)
     user_id = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
     payment_order_id = Column(
-        String(36), ForeignKey("payment_orders.id", ondelete="SET NULL"), nullable=True
+        String(36), ForeignKey("payment_orders.id", ondelete="SET NULL"), nullable=True, index=True
     )
 
     source_type = Column(String(30), nullable=False)  # payment_order/manual_recharge/card_recharge
@@ -696,9 +708,15 @@ class RefundRequest(Base):
 
     status = Column(String(30), nullable=False, default="pending_approval")
     reason = Column(Text, nullable=True)
-    requested_by = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
+    requested_by = Column(
-    approved_by = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
+        String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
-    processed_by = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
+    )
+    approved_by = Column(
+        String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    processed_by = Column(
+        String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
+    )
 
     gateway_refund_id = Column(String(128), nullable=True)
     payout_method = Column(String(50), nullable=True)
@@ -1125,6 +1143,7 @@ class ProxyNode(Base):
         String(36),
         ForeignKey("users.id", ondelete="SET NULL"),
         nullable=True,
+        index=True,
         comment="注册该节点的管理员用户 ID（可空）",
     )
     last_heartbeat_at = Column(DateTime(timezone=True), nullable=True)
@@ -1914,10 +1933,10 @@ class VideoTask(Base):
 
     # 关联
     user_id = Column(String(36), ForeignKey("users.id"), nullable=False)
-    api_key_id = Column(String(36), ForeignKey("api_keys.id"))
+    api_key_id = Column(String(36), ForeignKey("api_keys.id"), index=True)
-    provider_id = Column(String(36), ForeignKey("providers.id"))
+    provider_id = Column(String(36), ForeignKey("providers.id"), index=True)
-    endpoint_id = Column(String(36), ForeignKey("provider_endpoints.id"))
+    endpoint_id = Column(String(36), ForeignKey("provider_endpoints.id"), index=True)
-    key_id = Column(String(36), ForeignKey("provider_api_keys.id"))
+    key_id = Column(String(36), ForeignKey("provider_api_keys.id"), index=True)
 
     # 格式转换追踪
     client_api_format = Column(String(50), nullable=False)
@@ -1967,7 +1986,7 @@ class VideoTask(Base):
 
     # Remix 支持
     remixed_from_task_id = Column(
-        String(36), ForeignKey("video_tasks.id", ondelete="SET NULL"), nullable=True
+        String(36), ForeignKey("video_tasks.id", ondelete="SET NULL"), nullable=True, index=True
     )
 
     # 使用追踪（候选 key、请求头等）
@@ -2021,7 +2040,7 @@ class UserPreference(Base):
     bio = Column(Text, nullable=True)  # 个人简介
 
     # 偏好设置
-    default_provider_id = Column(String(36), ForeignKey("providers.id"), nullable=True)
+    default_provider_id = Column(String(36), ForeignKey("providers.id"), nullable=True, index=True)
     theme = Column(String(20), default="light")  # light/dark/auto
     language = Column(String(10), default="zh-CN")
     timezone = Column(String(50), default="Asia/Shanghai")
@@ -2059,7 +2078,9 @@ class Announcement(Base):
     priority = Column(Integer, default=0)  # 优先级,数字越大越重要
 
     # 发布信息
-    author_id = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
+    author_id = Column(
+        String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
+    )
     is_active = Column(Boolean, default=True, index=True)
     is_pinned = Column(Boolean, default=False)  # 置顶
 
@@ -2095,7 +2116,7 @@ class AnnouncementRead(Base):
 
     id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
     user_id = Column(String(36), ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
-    announcement_id = Column(String(36), ForeignKey("announcements.id"), nullable=False)
+    announcement_id = Column(String(36), ForeignKey("announcements.id"), nullable=False, index=True)
     read_at = Column(
         DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False
     )
@@ -2373,18 +2394,28 @@ class RequestCandidate(Base):
 
     # 关联字段
     request_id = Column(String(100), nullable=False, index=True)
-    user_id = Column(String(36), ForeignKey("users.id", ondelete="CASCADE"), nullable=True)
+    user_id = Column(
-    api_key_id = Column(String(36), ForeignKey("api_keys.id", ondelete="CASCADE"), nullable=True)
+        String(36), ForeignKey("users.id", ondelete="CASCADE"), nullable=True, index=True
+    )
+    api_key_id = Column(
+        String(36), ForeignKey("api_keys.id", ondelete="CASCADE"), nullable=True, index=True
+    )
 
     # 候选信息
     candidate_index = Column(Integer, nullable=False)  # 候选序号（从0开始）
     retry_index = Column(Integer, nullable=False, default=0)  # 重试序号（从0开始）
     provider_id = Column(String(36), ForeignKey("providers.id", ondelete="CASCADE"), nullable=True)
     endpoint_id = Column(
-        String(36), ForeignKey("provider_endpoints.id", ondelete="CASCADE"), nullable=True
+        String(36),
+        ForeignKey("provider_endpoints.id", ondelete="CASCADE"),
+        nullable=True,
+        index=True,
     )
     key_id = Column(
-        String(36), ForeignKey("provider_api_keys.id", ondelete="CASCADE"), nullable=True
+        String(36),
+        ForeignKey("provider_api_keys.id", ondelete="CASCADE"),
+        nullable=True,
+        index=True,
     )
 
     # 状态信息