ADR 0006: Storage abstraction#

Context#

Notebooks need no database while platforms need atomic incremental persistence and SQL.

Decision#

Use a narrow storage port with memory, atomic partitioned Parquet, and optional DuckDB adapters.

Alternatives#

A required database, ORM, or one global cache was considered.

Consequences#

Core installation stays light and storage is replaceable.

Rejected shortcuts#

Provider-side writes and non-atomic partition replacement are rejected.

Operational implications#

Primary-key merge, manifests, checksums, partitions, and checkpoints govern reruns.