> 1. Not actual due to 2, but it would be better to use
>   `pOp->p5 &= ~OPFLAG_XFER_OPT` to drop just that flag.
> 2. It is counter-intuitive, IMHO, to change operation flags during that
>   operation. So, said above, vote to move it to OP_OpenWrite.

Well, actually moving it to OP_OpenWrite seems to be bad idea.
Even if code for xFer optimisation is generated, it
still might not be executed. The only opcode ensuring xFer is
under processing - OP_RowData.