Function ProcessOrClauseForPossibleValues

src/backend/optimizer/util/predtest.c:2274–2309

* Process an OR clause -- this can do a UNION between sets learned from child clauses */

 * Process an OR clause -- this can do a UNION between sets learned from child clauses
 */
static PossibleValueSet
ProcessOrClauseForPossibleValues( PredIterInfoData *clauseInfo, Node *clause, Node *variable, Oid opfamily)
{
	PossibleValueSet result;
	InitPossibleValueSetData(&result);

	iterate_begin(child, clause, *clauseInfo)
	{
		PossibleValueSet childPossible = DeterminePossibleValueSet( child, variable, opfamily);
		if ( childPossible.isAnyValuePossible)
		{
			/* any value is possible for the entire AND */
			DeletePossibleValueSetData( &childPossible );
			DeletePossibleValueSetData( &result );

			/* it can't improve once a part of the OR accepts all, so just quit */
			result.isAnyValuePossible = true;
			break;
		}

		if ( result.isAnyValuePossible )
		{
			/* first one in loop so just take it */
			result = childPossible;
		}
		else
		{
			/* result.set OR childPossible.set --> do union into result */
			AddUnmatchingValues( &result, &childPossible );
			DeletePossibleValueSetData( &childPossible);
		}
	}
	iterate_end(*clauseInfo);

	return result;
}


/**