Renaming
ALTER TABLE ... RENAME COLUMN
Instant metadata-only on PostgreSQL 14+; still takes ACCESS EXCLUSIVE with no non-blocking alternative pre-14
ALTER TABLE orders RENAME COLUMN status TO order_status;What this does
A pure catalog rename, no table scan or rewrite. On PostgreSQL 14 and later the ACCESS EXCLUSIVE lock is brief and metadata-only. On earlier versions the lock mode is the same but there is no non-blocking alternative available, so plan for a maintenance window or use expand/contract if the rename must be zero-downtime.