# ADR-038: SQLite-First, Postgres Removed

## Status

Accepted

## Context

The original architecture specified two database hosts: SQLite for spokes (local/embedded) and PostgreSQL for the hub (central service). This required:

- Maintaining two sets of Drizzle table definitions (`sqliteTable` and `pgTable`) with the same logical shapes
- Two client factories (`createSqliteDatabase`, `createPostgresDatabase`)
- Two repository layer implementations or a host-agnostic abstraction
- Separate test suites for each host
- A PostgreSQL server as infrastructure dependency for any hub deployment

The dual-host model came from the `@ade` POC, which was single-tenant and didn't account for multi-tenant deployment concerns. For the actual use case — small teams of developers and AI agents sharing compute — PostgreSQL is operational overhead without proportional benefit.

## Decision

`@alkdev/storage` is SQLite-only. The `pg/` subpath export is removed. The package provides one database host: SQLite via the Honker extension (see ADR-039).

This eliminates:

- All `pgTable` definitions and the `src/pg/` directory
- The PostgreSQL porting notes in every spec document
- Dual schema maintenance, dual testing, dual repository implementations
- PostgreSQL and Redis as infrastructure dependencies

## Consequences

**Positive:**

- Single set of table definitions, one client factory, one test suite
- No PostgreSQL server to install, configure, secure, and maintain
- No Redis for pub/sub — Honker provides durable pub/sub within SQLite
- Simpler deployment: a single `.db` file per database
- The hub's domain tables can coexist with metagraph tables in the same SQLite file
- WAL mode with Honker's reader pool provides sufficient concurrency for the expected workload

**Negative:**

- SQLite is single-machine — no horizontal scaling, no read replicas, no cross-server queries
- No native `jsonb` type with GIN indexes — JSON attributes rely on `json_extract()` queries
- No built-in full-text search on JSON attributes (SQLite FTS5 works but requires manual setup)
- Some ecosystem tools expect PostgreSQL (migration tools, monitoring dashboards)
- If a future deployment genuinely needs PostgreSQL scale, a migration path would need to be rebuilt

## References

- ADR-039: Honker as SQLite extension and pub/sub transport
- ADR-040: System DB + tenant DB separation
- ADR-018 (superseded): dbtype integration was partly motivated by PG/SQLite dual maintenance; with PG removed, this pressure is reduced