Re: [HACKERS] pageinspect and hash indexes

Ashutosh Sharma <ashu.coek88@gmail.com> writes:
> Basically, when we started working on WAL for hash index, we found
> that WAL routine 'XLogReadBufferExtended' does not expect a page to be
> completely zero page else it returns Invalid Buffer. To fix this, we
> started initializing freed overflow page or new bucket pages using
> _hash_pageinit() which basically initialises page header portion but
> not it's special area where page type information is present. That's
> why you are seeing an ERROR saying 'page is not a hash page'. Actually
> pageinspect module needs to handle this type of page. Currently it is
> just handling zero pages but not an empty pages. I will submit a patch
> for this.

That seems like entirely the wrong approach.  You should make the special
space valid, instead, so that tools like pg_filedump can make sense of
the page.
        regards, tom lane