Class MultiJoinOptimizeBushyRule

All Implemented Interfaces:

@Enclosing public class MultiJoinOptimizeBushyRule extends RelRule<MultiJoinOptimizeBushyRule.Config> implements TransformationRule
Planner rule that finds an approximately optimal ordering for join operators using a heuristic algorithm.

It is triggered by the pattern LogicalProject (MultiJoin).

It is similar to LoptOptimizeJoinRule (CoreRules.MULTI_JOIN_OPTIMIZE). LoptOptimizeJoinRule is only capable of producing left-deep joins; this rule is capable of producing bushy joins.


  1. Join conditions that touch 1 factor.
  2. Join conditions that touch 3 factors.
  3. More than 1 join conditions that touch the same pair of factors, e.g. t0.c1 = t1.c1 and t1.c2 = t0.c3
See Also: