Function predicate_classify

src/backend/optimizer/util/predtest.c:831–907

* predicate_classify * Classify an expression node as AND-type, OR-type, or neither (an atom). * * If the expression is classified as AND- or OR-type, then *info is filled * in with the functions needed to iterate over its components. * * This function also implements enforcement of MAX_SAOP_ARRAY_SIZE: if a * ScalarArrayOpExpr's array has too many elements, we just classify it as an * a

 * that would result in wrong proofs, rather than failing to prove anything.
 */
static PredClass
predicate_classify(Node *clause, PredIterInfo info)
{
	/* Caller should not pass us NULL, nor a RestrictInfo clause */
	Assert(clause != NULL);
	Assert(!IsA(clause, RestrictInfo));

	/*
	 * If we see a List, assume it's an implicit-AND list; this is the correct
	 * semantics for lists of RestrictInfo nodes.
	 */
	if (IsA(clause, List))
	{
		info->startup_fn = list_startup_fn;
		info->next_fn = list_next_fn;
		info->cleanup_fn = list_cleanup_fn;
		return CLASS_AND;
	}

	/* Handle normal AND and OR boolean clauses */
	if (is_andclause(clause))
	{
		info->startup_fn = boolexpr_startup_fn;
		info->next_fn = list_next_fn;
		info->cleanup_fn = list_cleanup_fn;
		return CLASS_AND;
	}
	if (is_orclause(clause))
	{
		info->startup_fn = boolexpr_startup_fn;
		info->next_fn = list_next_fn;
		info->cleanup_fn = list_cleanup_fn;
		return CLASS_OR;
	}

	/* Handle ScalarArrayOpExpr */
	if (IsA(clause, ScalarArrayOpExpr))
	{
		ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) clause;
		Node	   *arraynode = (Node *) lsecond(saop->args);

		/*
		 * We can break this down into an AND or OR structure, but only if we
		 * know how to iterate through expressions for the array's elements.
		 * We can do that if the array operand is a non-null constant or a
		 * simple ArrayExpr.
		 */
		if (arraynode && IsA(arraynode, Const) &&
			!((Const *) arraynode)->constisnull)
		{
			ArrayType  *arrayval;
			int			nelems;

			arrayval = DatumGetArrayTypeP(((Const *) arraynode)->constvalue);
			nelems = ArrayGetNItems(ARR_NDIM(arrayval), ARR_DIMS(arrayval));
			if (nelems <= MAX_SAOP_ARRAY_SIZE)
			{
				info->startup_fn = arrayconst_startup_fn;