Teodor Sigaev <teodor@sigaev.ru> writes:
>> Rather than eating up the extra flag bit, though, would it be possible
>> to change the tuple to appear to contain a NULL?
> We would like to preserve NULL as non-special value because we hope to add
> support of NULLs to GiST, although it's of low priority.
Fair enough.
> In other side, IndexTupleData contains ItemPointerData which contains
> block number and offset. GiST doesn't use offset on inner pages (on
> leaf pages, ItemPointerData points to heap tuple), it always equal
> FirstOffsetNumber. So I can use offset to indicate correctness of
> tuple's key...
OK, that's a tad klugy but I agree with the approach. I'd like to
preserve the spare flag bit in IndexTuple->t_info --- we might need
that someday.
regards, tom lane