I think I'm missing something... In this patch, I see you writing WAL records for hint-bits (bufmgr.c FlushBuffer). But doesn't XLogInsert then make a "backup block" record (unless it's already got one since last checkpoint)?
Once there's a backup block record, the torn-page problem that causes the whole CRCs to not validate, isn't it? On crash/recovery, you won't read this torn block because the WAL log will have the old backup + any possible updates to it... Sorry if I'm missing something very obvious... a. * Alvaro Herrera <[EMAIL PROTECTED]> [081113 13:08]: > I see. > > Since our CRC implementation is a simple byte loop, and since ItemIdData > fits in a uint32, the attached patch should do mostly the same by > copying the line pointer into a uint32, turning off the lp_flags, and > summing the modified copy. > > This patch is also skipping pd_special and the unused area of the page. > > I'm still testing this; please beware that this likely has an even > higher bug density than my regular patches (and some debugging printouts > as well). > > While reading the pg_filedump code I noticed that there's a way to tell > the different index pages apart, so perhaps we can use that to be able > to checksum the special space as well. -- Aidan Van Dyk Create like a god, [EMAIL PROTECTED] command like a king, http://www.highrise.ca/ work like a slave.
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