Re: Page Checksums

Jeff Davis <pgsql@j-davis.com>

From: Jeff Davis <pgsql@j-davis.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Simon Riggs <simon@2ndquadrant.com>, Josh Berkus <josh@agliodbs.com>, pgsql-hackers@postgresql.org
Date: 2011-12-27T18:39:36Z
Lists: pgsql-hackers
On Mon, 2011-12-19 at 07:50 -0500, Robert Haas wrote:
> I
> think it would be regrettable if everyone had to give up 4 bytes per
> page because some people want checksums.

I can understand that some people might not want the CPU expense of
calculating CRCs; or the upgrade expense to convert to new pages; but do
you think 4 bytes out of 8192 is a real concern?

(Aside: it would be MAXALIGNed anyway, so probably more like 8 bytes.)

I was thinking we'd go in the other direction: expanding the header
would take so much effort, why not expand it a little more to give some
breathing room for the future?

Regards,
	Jeff Davis