先决条件 本指南假设您熟悉 LangSmith、持久化 和跨线程持久化概念。
LangSmith 持久化检查点（线程状态）和跨线程内存（存储项）。在 langgraph.json 中配置生存时间（TTL）策略以自动管理此数据的生命周期，防止无限期累积。

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Configuring checkpoint TTL

Checkpoints capture the state of conversation threads. Setting a TTL ensures old checkpoints and threads are automatically deleted. Add a checkpointer.ttl configuration to your langgraph.json file: 
{
  "dependencies": ["."],
  "graphs": {
    "agent": "./agent.py:graph"
  },
  "checkpointer": {
    "ttl": {
      "strategy": "delete",
      "sweep_interval_minutes": 60,
      "default_ttl": 43200
    }
  }
}
  • strategy: Specifies the action taken on expiration. Currently, only "delete" is supported, which deletes all checkpoints in the thread upon expiration.
  • sweep_interval_minutes: Defines how often, in minutes, the system checks for expired checkpoints.
  • default_ttl: Sets the default lifespan of threads (and corresponding checkpoints) in minutes (e.g., 43200 minutes = 30 days). Applies only to checkpoints created after this configuration is deployed; existing checkpoints/threads are not changed. To clear older data, delete it explicitly.

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Configuring store item TTL

Store items allow cross-thread data persistence. Configuring TTL for store items helps manage memory by removing stale data. Add a store.ttl configuration to your langgraph.json file: 
{
  "dependencies": ["."],
  "graphs": {
    "agent": "./agent.py:graph"
  },
  "store": {
    "ttl": {
      "refresh_on_read": true,
      "sweep_interval_minutes": 120,
      "default_ttl": 10080
    }
  }
}
  • refresh_on_read: (Optional, default true) If true, accessing an item via get or search resets its expiration timer. If false, TTL only refreshes on put.
  • sweep_interval_minutes: (Optional) Defines how often, in minutes, the system checks for expired items. If omitted, no sweeping occurs.
  • default_ttl: (Optional) Sets the default lifespan of store items in minutes (e.g., 10080 minutes = 7 days). Applies only to items created after this configuration is deployed; existing items are not changed. If you need to clear older items, delete them manually. If omitted, items do not expire by default.

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Combining TTL configurations

You can configure TTLs for both checkpoints and store items in the same langgraph.json file to set different policies for each data type. Here is an example: 
{
  "dependencies": ["."],
  "graphs": {
    "agent": "./agent.py:graph"
  },
  "checkpointer": {
    "ttl": {
      "strategy": "delete",
      "sweep_interval_minutes": 60,
      "default_ttl": 43200
    }
  },
  "store": {
    "ttl": {
      "refresh_on_read": true,
      "sweep_interval_minutes": 120,
      "default_ttl": 10080
    }
  }
}

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Runtime overrides

The default store.ttl settings from langgraph.json can be overridden at runtime by providing specific TTL values in SDK method calls like get, put, and search.

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Deployment process

After configuring TTLs in langgraph.json, deploy or restart your LangGraph application for the changes to take effect. Use langgraph dev for local development or langgraph up for Docker deployment. See the langgraph.json CLI reference for more details on the other configurable options.
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