Why do we have MakeSingleTupleTableSlot instead of not using MakeTupleTableSlot?

Hi,

I wonder, is there a specific reason that MakeTupleTableSlot is
wrapped up in MakeSingleTupleTableSlot without doing anything than
just returning the slot created by MakeTupleTableSlot? Do we really
need MakeSingleTupleTableSlot? Can't we just use MakeTupleTableSlot
directly? Am I missing something?

I think we can avoid some unnecessary function call costs, for
instance when called 1000 times inside table_slot_create from
copyfrom.c or in some other places where MakeSingleTupleTableSlot is
called in a loop.

If it's okay to remove MakeSingleTupleTableSlot and use
MakeTupleTableSlot instead, we might have to change in a lot of
places. If we don't want to change in those many files, we could
rename MakeTupleTableSlot to MakeSingleTupleTableSlot and change it in
only a few places.

Thoughts?

With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com