Re: [SPAM] Re: BUG #3484: Missing pg_clog file / corrupt index

[Gregory Stark <stark(at)enterprisedb(dot)com>]

"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Remember that the xmin/xmax fields are basically the first thing we can
> check with any degree of strictness when examining a tuple. This means that
> if a page is partially clobbered, but not in a way that sets off the
> invalid-page-header checks, then the odds are very high that the first
> detectable sign of trouble will be references to transaction numbers that
> are far away from what the system is really using.

I'm increasingly thinking that one of the first things I'll suggest putting
into 8.4 is a per-page checksum after all. It was talked about a while back
and people thought it was pointless but I think the number of reports of
hardware and kernel bugs resulting in zeroed and corrupted pages has been
steadily going up. If not in total than as a percentage of the total problems.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com