PostgreSQL 19 enables data checksums without stopping the server

PostgreSQL 19 (beta 3, general release around September-October 2026) adds pg_enable_data_checksums() and pg_disable_data_checksums(), letting clusters change checksum state while serving traffic. Checksums are now enabled by default in new clusters.

• Functions run via a background worker while the server keeps serving queries
• Data checksums are enabled by default in fresh PostgreSQL 19 clusters
• Enabling on a 776MB database generates about 799MB of WAL; disabling writes 512 bytes
• Progress is exposed in pg_stat_progress_data_checksums, throttling via cost_delay and cost_limit