Package org.apache.calcite.materialize

Class LatticeSuggester.Hop

  • Enclosing class:
    LatticeSuggester
    private static class LatticeSuggester.Hop
extends java.lang.Object
    A hop is a join condition. One or more hops between the same source and target combine to form a Step.

    The tables are registered but the step is not. After we have gathered several join conditions we may discover that the keys are composite: e.g. 

         x.a = y.a
     AND x.b = z.b
     AND x.c = y.c

    has 3 semi-hops:

    • x.a = y.a
    • x.b = z.b
    • x.c = y.c

    which turn into 2 steps, the first of which is composite:

    • x.[a, c] = y.[a, c]
    • x.b = z.b