[loeg]

That's measuring 'cksum', which must have an awfully slow implementation. The document notes that this is distinct from measuring PG's checksum performance. (I think it's a pretty useless measurement.)

Earlier (page 4):

> How much CPU time does it take to checksum...

> ...a specific amount of data? This is easy to estimate because PostgreSQL uses the crc32 algorithm which is very simple, and (GNU) Linux has a command line program that does the same thing: cksum.

Yeah, using cksum as an estimate here appears to be very flawed.

[Joe_Cool]

That is weird. Seems like crc optimization is quite a rabbit hole.

https://github.com/komrad36/CRC has a massive section about it in the README. Really interesting.

[loeg]

Yeah. crc32 may be simple in theory, but doing it as fast as possible utilizing the various execution units of modern hardware is challenging.