Investigated three approaches for CH 24.12:
- Inline SETTINGS on ADD PROJECTION: rejected (UNKNOWN_SETTING — not a query-level setting).
- ALTER TABLE MODIFY SETTING deduplicate_merge_projection_mode='rebuild': works; persists in
table metadata across connection restarts; runs before ADD PROJECTION in the SQL script.
- Session-level JDBC URL param: not pursued (MODIFY SETTING is strictly better).
alerting_projections.sql now runs MODIFY SETTING before the two executions ADD PROJECTIONs.
AlertingProjectionsIT strengthened to assert all four projections (including alerting_app_status
and alerting_route_status on executions) exist after schema init.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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