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Default Behavior

  • LangGraph adapter uses memory checkpointing by default.
  • If POSTGRES_URL is configured and database initialization succeeds, the adapter can use PostgreSQL-backed checkpointing.
  • During plugin initialization, checkpointer tables are set up when needed.

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Operational Guidance

  • Use memory checkpointing for local development and simple test flows.
  • Use PostgreSQL checkpointing for durable state across restarts and distributed deployments.
  • Validate database connectivity before starting production workloads.

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PostgreSQL Setup

Under aion serve the adapter attaches the checkpointer itself, and [langgraph-server] covers Postgres checkpointing. Point it at a database and it switches backends:
Without POSTGRES_URL the checkpointer is in-memory. With it set, the checkpointer is PostgreSQL: if the database cannot be reached or the checkpointer fails to initialize, startup fails with an error. The startup logs name the backend it chose. Return the graph uncompiled — a StateGraph, or a callable that returns one. Aion compiles it and attaches the checkpointer for you. A graph that arrives already compiled is used as it is, and keeps whichever checkpointer it was compiled with, so POSTGRES_URL has no effect on it.