Re: better page-level checksums

On Tue, Jun 14, 2022 at 9:56 PM Peter Geoghegan <pg@bowt.ie> wrote:
> Technically we don't already do that today, with the 16-bit checksums
> that are stored in PageHeaderData.pd_checksum. But we do something
> equivalent: low-level tools can still infer that checksums must not be
> enabled on the page (really the cluster) indirectly in the event of a
> 0 checksum. A 0 value can reasonably be interpreted as a page from a
> cluster without checksums (barring page corruption). This is basically
> reasonable because our implementation of checksums is guaranteed to
> not generate 0 as a valid checksum value.

I don't think that 'pg_checksums -d' zeroes the checksum values on the
pages in the cluster.

-- 
Robert Haas
EDB: http://www.enterprisedb.com