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

From Tom Lane
Subject Re: Block-level CRC checks
Date
Msg-id 27681.1222955876@sss.pgh.pa.us
Whole thread Raw
In response to Re: Block-level CRC checks  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: Block-level CRC checks
List pgsql-hackers
Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
> Brian Hurt wrote:
>> Another possibility is to just not checksum the hint bits...

> That would work. But I'm afraid it'd make the implementation a lot more 
> invasive, and also slower. The buffer manager would have to know what 
> kind of a page it's dealing with, heap or index or FSM or what, to know 
> where the hint bits are. Then it would have to follow the line pointers 
> to locate the hint bits, and mask them out for the CRC calculation.

Right.  The odds are that this'd actually be slower than the
double-buffer method, because of all the added complexity.  And it would
really suck from a modularity standpoint to have bufmgr know about all
that.

The problem we still have to solve is torn pages when writing back a
hint-bit update ...
        regards, tom lane


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