2026-03-01 - MySQL Tx Cursor Safety In Recompute/Rebuild Flows

Date: 2026-03-01
Decision:
- In transactional MySQL/MariaDB code, prohibit nested SQL calls on the same tx while iterating an open cursor (for rows.Next()).
- Use a mandatory two-phase approach: read all rows -> close cursor -> execute follow-up reads/writes.
Context:
- History recompute/rebuild jobs produced persistent driver failures:
  - [mysql] invalid connection
  - unexpected EOF
  - driver: bad connection
- DB logs showed repeated aborted client connections (Got an error reading communication packets).
- Root cause pattern was SQL execution on the same transaction while a result cursor was still active.
Consequences:
- Recompute/rebuild code paths must be audited and kept cursor-safe.
- Future projection rebuild and repair flows must follow two-phase read/write design by default.
- Runtime invariant documented in bible-local/architecture/runtime-flows.md.
Supersedes:
- None.