Re: Block-level CRC checks

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