On Sat, Mar 18, 2017 at 1:42 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Ashutosh Sharma <ashu.coe...@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. >
We were not aware that external tools like pg_filedump are dependent on special space of index, but after looking at the code of pg_filedump, I agree with you that we need to initialize the special space in this case (free overflow page). I think we can mark such a page type as LH_UNUSED_PAGE and then initialize the other fields of special space. Nonetheless, I think we still need modifications in hashfuncs.c so that it can understand this type of page. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
