Function MakeTidOpExpr

src/backend/executor/nodeTidrangescan.c:52–95

* For the given 'expr', build and return an appropriate TidOpExpr taking into * account the expr's operator and operand order. */

 * account the expr's operator and operand order.
 */
static TidOpExpr *
MakeTidOpExpr(OpExpr *expr, TidRangeScanState *tidstate)
{
	Node	   *arg1 = get_leftop((Expr *) expr);
	Node	   *arg2 = get_rightop((Expr *) expr);
	ExprState  *exprstate = NULL;
	bool		invert = false;
	TidOpExpr  *tidopexpr;

	if (IsCTIDVar(arg1))
		exprstate = ExecInitExpr((Expr *) arg2, &tidstate->ss.ps);
	else if (IsCTIDVar(arg2))
	{
		exprstate = ExecInitExpr((Expr *) arg1, &tidstate->ss.ps);
		invert = true;
	}
	else
		elog(ERROR, "could not identify CTID variable");

	tidopexpr = (TidOpExpr *) palloc(sizeof(TidOpExpr));
	tidopexpr->inclusive = false;	/* for now */

	switch (expr->opno)
	{
		case TIDLessEqOperator:
			tidopexpr->inclusive = true;
			/* fall through */
		case TIDLessOperator:
			tidopexpr->exprtype = invert ? TIDEXPR_LOWER_BOUND : TIDEXPR_UPPER_BOUND;
			break;
		case TIDGreaterEqOperator:
			tidopexpr->inclusive = true;
			/* fall through */
		case TIDGreaterOperator:
			tidopexpr->exprtype = invert ? TIDEXPR_UPPER_BOUND : TIDEXPR_LOWER_BOUND;
			break;
		default:
			elog(ERROR, "could not identify CTID operator");
	}

	tidopexpr->exprstate = exprstate;

	return tidopexpr;
}

/*
 * Extract the qual subexpressions that yield TIDs to search for,