Re: Block-level CRC checks - Mailing list pgsql-hackers

From Gregory Stark
Subject Re: Block-level CRC checks
Date
Msg-id 87y717glkw.fsf@oxford.xeocode.com
Whole thread Raw
In response to Re: Block-level CRC checks  ("Jonah H. Harris" <jonah.harris@gmail.com>)
Responses Re: Block-level CRC checks
List pgsql-hackers
"Jonah H. Harris" <jonah.harris@gmail.com> writes:

> On Thu, Oct 2, 2008 at 9:07 AM, Brian Hurt <bhurt@janestcapital.com> wrote:
>> I have a stupid question wrt hint bits and CRC checksums- it seems to me
>> that it should be possible, if you change the hint bits, to be able to very
>> easily calculate what the change in the CRC checksum should be.
>
> Doesn't the problem still remain?  The problem being that the buffer
> can be changed as it's written, yes?

It's even worse than that. Two processes can both be fiddling hint bits on
different tuples (or even the same tuple) at the same time.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's RemoteDBA services!


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