Re: Idea for getting rid of VACUUM FREEZE on cold pages

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> ... my perspective is that it would be A Good Thing if it could
> just be turned on when needed.  If you have recurring bug that can
> be arranged, but in those cases you have other options; so I'm
> assuming you want this kept because it is primarily of forensic
> value after a non-repeatable bug has munged something?
Yeah, that's exactly the problem.  When you realize you need it,
it's too late.

> The best thought I've had so far
> is that if someone kept WAL files long enough the evidence might be
> in there somewhere....

Hm, that is an excellent point.  The WAL trace would actually be a lot
superior in terms of being able to figure out what went wrong.  But
I don't quite see how we tell people "either keep xmin or keep your
old WAL".  Also, for production sites the amount of WAL you'd have to
hang onto seems a bit daunting.  Other problems are the cost of shipping
it to a developer, and the impracticality of sanitizing private data in
it before you show it to somebody.
        regards, tom lane