Function flatten_logic_exprs

src/backend/executor/execUtils.c:1423–1452

* flatten_logic_exprs * This function is only used by ExecPrefetchJoinQual. * ExecPrefetchJoinQual need to prefetch subplan in join * qual that contains motion to materialize it to avoid * motion deadlock. This function is going to flatten * the bool exprs to avoid shortcut of bool logic. * An example is: * (a and b or c) or (d or e and f or g) and (h and i or j) * will be transformed to

 * (a, b, c, d, e, f, g, h, i, j).
 */
static List *
flatten_logic_exprs(Node *node)
{
	if (node == NULL)
		return NIL;

	if (IsA(node, BoolExpr))
	{
		BoolExpr *be = (BoolExpr *) node;
		return flatten_logic_exprs((Node *) (be->args));
	}

	if (IsA(node, List))
	{
		List     *es = (List *) node;
		List     *result = NIL;
		ListCell *lc = NULL;

		foreach(lc, es)
		{
			Node *n = (Node *) lfirst(lc);
			result = list_concat(result,
								 flatten_logic_exprs(n));
		}

		return result;
	}

	return list_make1(node);
}

/*
 * fake_outer_params