backend

Database Migrations

Migration 5 - Checkpoint Management Update

This migration introduces a significant change to thread checkpoint management:

Changes

• Transitions from single-table pickle storage to a robust multi-table checkpoint management system
• Implements LangGraph's latest checkpoint architecture for improved state persistence
• Preserves existing checkpoint data by renaming checkpoints table to old_checkpoints
• Introduces three new tables for better checkpoint management:
  • checkpoints: Core checkpoint metadata
  • checkpoint_blobs: Actual checkpoint data storage (compatible with LangGraph state serialization)
  • checkpoint_writes: Tracks checkpoint write operations
• Adds runtime initialization via ensure_setup() in the lifespan event

Impact

• Breaking Change: Historical threads/checkpoints (pre-migration) will not be accessible in the UI
• Previous checkpoint data remains preserved but inaccessible in the new system
• Designed to work seamlessly with LangGraph's state persistence requirements

Migration Details

• Up Migration: Safely preserves existing data by renaming the table
• Down Migration: Restores original table structure if needed
• New checkpoint management tables are automatically created at application startup