That work is done by the decorators! They wrap around your functions and store the execution state of your workflows in Postgres, specifically:

- Which workflows are executing

- What their inputs were

- Which steps have completed

- What their outputs were

Here's a reference for the Postgres tables DBOS uses to manage that state: https://docs.dbos.dev/explanations/system-tables

All of this seems it would fit any transactional key value structure.