Re: [WIP] In-place upgrade

Tom Lane napsal(a):

>
> I concur that I don't want to see this patch adding more than the
> absolute unavoidable minimum of overhead for data that meets the
> "current" layout definition. I'm disturbed by the proposal to stick
> overhead into tuple header access, for example.

OK. I agree that it is overhead. However the patch contains also Tuple and Page
API cleanup which is general thing. All function should use HeapTuple access not
HeapTupleHeader. I used function in the patch because I added multi version
access, but they can be macro.

The main change of page API is to add two function PageGetHeapTuple and
PageGetIndexTuple. I also add function like PageItemIsDead and so on. These
change are not only related to upgrade.

I accepting your complains about Tuples, but I think we should have multi page
version access method. The main advantage is that indexes are ready for reading
without any problem. It helps mostly in TOAST chunk data access and it is
necessary for retoasting. OK it will works until somebody change btree ondisk
format, but now it helps.

Zdenek