# ADR-001: HTAP via Delta-Merge (HANA-inspired)

**Status:** Accepted

## Decision
PaulDB implements HTAP through a Delta (Row-Store) + Main (Column-Store) split,
merged periodically - mirroring SAP HANA's architecture.

## Rationale
Single-store systems force a choice between OLTP and OLAP performance.
The Delta-Merge pattern allows both: fast writes land in Delta (row-optimized),
analytics scan Main (column-optimized, compressed).

## Consequences
- Every query must union Delta + Main results.
- A merge worker must run periodically.
- The C ABI boundary (storage.h) cleanly separates both stores.