pg_checksums_ext is based on the pg_verify_checksums and pg_checksums
programs available in PostgreSQL version 11 and from 12, respectively. It can
verify, activate or deactivate checksums. Activating requires all database
blocks to be read and all page headers to be updated, so can take a long time
on a large database.
The database cluster needs to be shutdown cleanly in the case of checksum
activation or deactivation, while checksum verification can be performed
online, contrary to PostgreSQL's pg_checksums.
Other changes include the possibility to toggle progress reporting via the
SIGUSR1 signal, more fine-grained progress reporting and I/O rate limiting.
PostgreSQL versions since 9.3 are supported, the November 8th 2018 PostgreSQL point release is required.