Critical bugs fixed:
- SELECT now returns actual row data (was returning empty arrays)
- WHERE filter evaluation now works (was pass-through stub)
- ORDER BY sorting now works (was no-op)
- UPDATE execution implemented (was no-op stub)
- DELETE uses WHERE filter (was key-match only)
- B-Tree point reads return actual row data (was returning count only)
- EXPLAIN returns plan string (was computed then discarded)
- UNIQUE constraint uses B-Tree index (was memtable scan only)
- DEFAULT values work for int/bool/float (was string-only)
- HTTP /query returns real JSON rows with columns
- Docker healthcheck uses wget (Alpine has no curl)
Updated PLAN.md with honest status:
- Marked what's truly done vs stub vs not implemented
- Honest score: 8/10 (not 9.5/10)
- Clear list of what actually works in production
All 216 tests pass
- Added TxnManager to server and ExecutionContext
- Per-connection ExecutionContext with isolated transaction state
- BEGIN creates new transaction via MVCC
- INSERT/DELETE uses transaction write buffer when active
- COMMIT flushes write set to LSM-Tree
- ROLLBACK aborts and discards pending writes
- cloneForConnection() shares tables/btrees/data, isolates transactions
- All 216 tests pass
- NOT NULL, PRIMARY KEY, UNIQUE, DEFAULT constraint validation on INSERT
- B-Tree indexes created for PK and UNIQUE columns on CREATE TABLE
- Indexes auto-populated during INSERT
- SELECT uses B-Tree index for point reads (WHERE id = 'x')
- Indexes cleaned up on DROP TABLE
- EXPLAIN output shows index usage vs full scan
- All 216 tests pass