Pavel Borisov <pashkin.elfe@gmail.com> writes:
> The way that seems acceptable to me is to add (optional) nulls mask into
> the end of existing style SpGistLeafTuple header and use indextuple
> routines to attach attributes after it. In this case, we can reduce the
> amount of code at the cost of adding one extra MAXALIGN size to the overall
> tuple size on 32-bit arch as now tuple header size of 12 bit already fits 3
> MAXALIGNS (on 64 bit the header now is shorter than 2 maxaligns (12 bytes
> of 16) and nulls mask will be free of cost). If you mean this I try to make
> changes soon. What do you think of it?
Yeah, that was pretty much the same conclusion I came to. For
INDEX_MAX_KEYS values up to 32, the nulls bitmap will fit into what's
now padding space on 64-bit machines. For backwards compatibility,
we'd have to be careful that the code knows there's no nulls bitmap in
an index without included columns, so I'm not sure how messy that will
be. But it's worth trying that way to see how it comes out.
regards, tom lane