Memory And State Langgraph

Integrator ships MemorySaver (in-process dict) to production and loses all conversation state on every deploy/restart.

Use MemorySaver only for development/tests; for production use a durable checkpointer (SqliteSaver for single-node, PostgresSaver for multi-node) so thread state survives restarts and is shared across workers. Match the checkpointer to the deployment topology.

Two users share one thread_id, so user B sees user A's conversation history through the checkpointer.

Scope thread_id to a single conversation/user and derive it from an authenticated identity, never a guessable/shared value. State restored for a thread_id is visible to anyone using it, so thread_id is a tenancy boundary.

Integrator uses PostgresSaver but never runs its setup/migration, so checkpoint writes fail at runtime with missing-table errors.

Initialize the persistent checkpointer (e.g., call its setup() / run migrations) before first use, and manage the connection lifecycle. Verify checkpoint reads/writes against the backend in staging; do not assume tables exist.