Class RelOptPredicateList


  • public class RelOptPredicateList
    extends java.lang.Object
    Predicates that are known to hold in the output of a particular relational expression.

    Pulled up predicates (field pulledUpPredicates are predicates that apply to every row output by the relational expression. They are inferred from the input relational expression(s) and the relational operator.

    For example, if you apply Filter(x > 1) to a relational expression that has a predicate y < 10 then the pulled up predicates for the Filter are [y < 10, x > 1].

    Inferred predicates only apply to joins. If there there is a predicate on the left input to a join, and that predicate is over columns used in the join condition, then a predicate can be inferred on the right input to the join. (And vice versa.)

    For example, in the query

    SELECT *
    FROM emp
    JOIN dept ON emp.deptno = dept.deptno WHERE emp.gender = 'F' AND emp.deptno < 10
    we have
    • left: Filter(Scan(EMP), deptno < 10, predicates: [deptno < 10]
    • right: Scan(DEPT), predicates: []
    • join: Join(left, right, emp.deptno = dept.deptno, leftInferredPredicates: [], rightInferredPredicates: [deptno < 10], pulledUpPredicates: [emp.gender = 'F', emp.deptno < 10, emp.deptno = dept.deptno, dept.deptno < 10]

    Note that the predicate from the left input appears in rightInferredPredicates. Predicates from several sources appear in pulledUpPredicates.

    • Field Detail

      • EMPTY_LIST

        private static final com.google.common.collect.ImmutableList<RexNode> EMPTY_LIST
      • pulledUpPredicates

        public final com.google.common.collect.ImmutableList<RexNode> pulledUpPredicates
        Predicates that can be pulled up from the relational expression and its inputs.
      • leftInferredPredicates

        public final com.google.common.collect.ImmutableList<RexNode> leftInferredPredicates
        Predicates that were inferred from the right input. Empty if the relational expression is not a join.
      • rightInferredPredicates

        public final com.google.common.collect.ImmutableList<RexNode> rightInferredPredicates
        Predicates that were inferred from the left input. Empty if the relational expression is not a join.
      • constantMap

        public final com.google.common.collect.ImmutableMap<RexNode,​RexNode> constantMap
        A map of each (e, constant) pair that occurs within pulledUpPredicates.
    • Constructor Detail

      • RelOptPredicateList

        private RelOptPredicateList​(com.google.common.collect.ImmutableList<RexNode> pulledUpPredicates,
                                    com.google.common.collect.ImmutableList<RexNode> leftInferredPredicates,
                                    com.google.common.collect.ImmutableList<RexNode> rightInferredPredicates,
                                    com.google.common.collect.ImmutableMap<RexNode,​RexNode> constantMap)
    • Method Detail

      • of

        public static RelOptPredicateList of​(RexBuilder rexBuilder,
                                             java.lang.Iterable<RexNode> pulledUpPredicates)
        Creates a RelOptPredicateList with only pulled-up predicates, no inferred predicates.

        Use this for relational expressions other than joins.

        Parameters:
        pulledUpPredicates - Predicates that apply to the rows returned by the relational expression
      • of

        public static RelOptPredicateList of​(RexBuilder rexBuilder,
                                             java.lang.Iterable<RexNode> pulledUpPredicates,
                                             java.lang.Iterable<RexNode> leftInferredPredicates,
                                             java.lang.Iterable<RexNode> rightInferredPredicates)
        Creates a RelOptPredicateList for a join.
        Parameters:
        rexBuilder - Rex builder
        pulledUpPredicates - Predicates that apply to the rows returned by the relational expression
        leftInferredPredicates - Predicates that were inferred from the right input
        rightInferredPredicates - Predicates that were inferred from the left input
      • concat

        private static <E> com.google.common.collect.ImmutableList<E> concat​(com.google.common.collect.ImmutableList<E> list1,
                                                                             com.google.common.collect.ImmutableList<E> list2)
        Concatenates two immutable lists, avoiding a copy it possible.