Materialized view refreshed without CONCURRENTLY

Warning — this works, but blocks traffic or rewrites data at scale.

What it catches

A plain REFRESH MATERIALIZED VIEW takes an exclusive lock on the view while it recomputes — every SELECT against it blocks for the whole rebuild. REFRESH ... CONCURRENTLY lets readers keep the old contents during the rebuild; it requires a unique index on the view.

Fires on

REFRESH MATERIALIZED VIEW daily_revenue;

Do this instead

-- one-time prerequisite, own migration outside a transaction:
--    CREATE UNIQUE INDEX CONCURRENTLY daily_revenue_day_idx
--      ON daily_revenue (day);
REFRESH MATERIALIZED VIEW CONCURRENTLY daily_revenue;