Greg Stark <gsstark@mit.edu> writes:
> On Fri, Feb 26, 2010 at 4:47 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> I feel the other one is easy. To store the hint bits inside the ItemId, in
>>> the place of size.
>>
>> No, we're not going there.
> Well we were already talking about moving the hint bits to someplace
> else to enable CRC checking. My favourite place was the line pointer,
> but you wanted a separate area -- either of which would have these
> problems.
IIRC, what was being talked about was shoehorning some hint bits into
the line pointers by assuming that size and offset are multiples of 4.
I'm not thrilled with having mutable status bits there for reliability
reasons, but it could be done without breaking a lot of existing code.
What I was reacting to above was a suggestion that we could delete the
itempointer size field altogether, which seems unworkable for the
reasons I mentioned.
regards, tom lane