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Re: Block-level CRC checks

From: Brian Hurt <bhurt(at)janestcapital(dot)com>
To:
Cc: Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Block-level CRC checks
Date: 2008-10-03 13:36:19
Message-ID: 48E61FD3.3060903@janestcapital.com (view raw or flat)
Thread:
Lists: pgsql-hackers
OK, I have a stupid question- torn pages are a problem, but only during 
recovery.  Recovery is (I assume) a fairly rare condition- if data 
corruption is going to happen, it's most likely to happen during normal 
operation.  So why not just turn off CRC checksumming during recovery, 
or at least treat it as a much less critical error?  During recovery, if 
the CRC checksum matches, we can assume the page is good- not only not 
corrupt, but not torn either.  If the CRC checksum doesn't match, we 
don't panic, but maybe we do more careful analysis of the page to make 
sure that only the hint bits are wrong.  Or maybe not.  It's only during 
normal operation that a CRC checksum failure would be considered critical.


Feel free to explain to me why I'm an idiot.

Brian


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Subject: Re: Block-level CRC checks
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