Re: Block-level CRC checks

On Tue, 2009-12-01 at 07:42 -0500, Bruce Momjian wrote:
> Simon Riggs wrote:
> > On Tue, 2009-12-01 at 07:05 -0500, Bruce Momjian wrote:
> > 
> > > I assume torn pages are 99% of the reported problem, which are
> > > expected and are fixed, and bad hardware 1%, quite the opposite of your
> > > numbers above.
> > 
> > On what basis do you make that assumption?
> 
> Because we added full page write protection to fix the reported problem
> of torn pages, which we had on occasion;  now we don't.  Bad hardware
> reports are less frequent.

Bad hardware reports are infrequent because we lack a detection system
for them, which is the topic of this thread. It would be circular to
argue that as a case against.

It's also an argument that only effects crashes.

-- Simon Riggs           www.2ndQuadrant.com