Re: Corrupt data pages...

Kevin Brown <kevin(at)sysexperts(dot)com> writes:
>> I'll put the files on a web server and post links to them here.
> You can find them here:
> https://gazebo.sysexperts.com/~kevin/postgresql

AFAICT, the first half of page 73 is OK, but the second half clearly is
trashed. In the raw-format dump it does look a whole lot like the
second half has been replaced by the first half of a page of some index.

It's fairly hard to see how that could happen inside Postgres. One can
readily imagine bugs that might replace one whole page with another,
but there aren't any operations that manipulate half-a-page. On the
other hand, if your kernel uses 4K blocksize, this could be explained
as substitution of one buffer for another at the kernel level. So my
money is on a kernel bug. As I mentioned, we've once or twice before
seen reports that looked like similar substitutions of single pages by
the kernel.

regards, tom lane