Checkpointers, Threads & Store
LangGraph persistence end to end: checkpointers and thread_id for resumable runs, get_state and time travel, PostgresSaver in production, and the Store for memory that outlives a thread.
Last updated
After this section you can
- Make a graph resumable with a checkpointer and a thread_id, and choose a backend and durability mode
- Inspect, replay and fork a run with get_state, get_state_history and update_state
- Keep cross-conversation facts in a store instead of growing one thread forever
36
Checkpointers, Threads & Store
One argument to compile() saves the state after every super-step, keyed by a thread. A second gives the agent memory that outlives the thread. They are different layers, and mixing them up is the usual bug.
Key idea
A checkpointer saves the graph state after every super-step under a thread_id, so a run can resume, be inspected or be replayed. A store keeps facts under a namespace you choose, outside every thread, so the next conversation can read them.
The checkpointer remembers this run; the store remembers this customer