Re: What exactly is our CRC algorithm?

At 2014-12-26 13:11:43 -0500, bruce@momjian.us wrote:
>
> Is this something that could potentially change the data stored on
> disk? Does pg_upgrade need to check for changes in this area?  Is the
> detection exposed by pg_controldata?  Could this affect running the
> data directory on a different CPU?

No to all.

Subsequent to Heikki's change (already in master) to use the CRC-32C
algorithm (instead of the earlier mistakenly-reflected-but-not-quite
one), both the slice-by-8 software implementation posted earlier and
the SSE4.2 CRC32* instructions will compute exactly the same value.

(Yes, I have verified this in both cases.)

-- Abhijit