If the block size the tool is compiled with does not match the data folder block size, then users would get incorrect checksums failures, which is confusing. As pg_checksum_block() uses directly the block size, this cannot really be made dynamic yet, so we had better issue an error on that. Michael Banck has sent a patch for that: https://www.postgresql.org/message-id/1552476561.4947.67.camel@credativ.de
The error message proposed is like that: + if (ControlFile->blcksz != BLCKSZ) + { + fprintf(stderr, _("%s: data directory block size %d is different to compiled-in block size %d.\n"), + progname, ControlFile->blcksz, BLCKSZ); + exit(1); + } Still I think that we could do better.
Here is a proposal of message which looks more natural to me, and more consistent with what xlog.c complains about: database files are incompatible with pg_checksums. The database cluster was initialized with BLCKSZ %d, but pg_checksums was compiled with BLCKSZ %d.
BLCKSZ is very much an internal term. The exposed name through pg_settings is block_size, so I think the original was better. Combining that one with yours into "initialized with block size %d" etc, makes it a lot nicer.
The "incompatible with pg_checksums" part may be a bit redundant with the commandname at the start as well, as I now realized Fabien pointed out downthread. But I would suggest just cutting it and saying "%s: database files are incompatible" or maybe "%s: data directory is incompatible" even?
