public class AST2BOpRTO extends AST2BOpJoins
Note: The RTO currently uses bottom-up evaluation to solve the join graph and generate a sub-query plan with an optimized join ordering. It uses left-to-right evaluation to pass pipeline solutions through the optimized subquery.
|Modifier and Type||Class and Description|
|Modifier and Type||Field and Description|
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Compile a join graph into a query plan.
Inspect the remainder of the join group.
Cutoff join of the last vertex in the join path.
addChunkedMaterializationStep, addMaterializationSteps1, addMaterializationSteps2, addMaterializationSteps3, addNonConditionalMaterializationSteps, getJoinConstraints, getJoinConstraints, getJoinConstraints2
applyQueryHints, applyQueryHints, leftOrEmpty
protected static PipelineOp convertRTOJoinGraph(PipelineOp left, JoinGroupNode joinGroup, Set<IVariable<?>> doneSet, AST2BOpContext ctx, AtomicInteger start)
Note: Two predicates in a join group is not enough for the RTO to provide a different join ordering. Both the static optimizer and the RTO will always choose the AP with the smaller cardinality to run first. If there are only 2 predicates, then the other predicate will run second. You need at least three predicates before the RTO could provide a different answer.
public static PipelineOp compileJoinGraph(QueryEngine queryEngine, JoinGraph joinGraph, Path path)
QueryEngineon which the RTO has been executing and on which the returned query plan may be executed.
joinGraph- The operator that executed the RTO.
path- The join path that was selected for full execution by the RTO based on deep sampling of the join graph.
JoinGraph.Annotations#JOIN_GROUPinto the ordering specified in the
Pathand make sure that convertJoinGroup() did not attempt to recursively reapply the RTO. This will get rid of one of the few remaining uses of
public static EdgeSample cutoffJoin(QueryEngine queryEngine, JoinGraph joinGraph, int limit, IPredicate<?> predicates, IConstraint constraints, boolean pathIsComplete, SampleBase sourceSample) throws Exception
The caller is responsible for protecting against needless re-sampling. This includes cases where a sample already exists at the desired sample limit and cases where the sample is already exact.
queryEngine- The query engine.
joinGraph- The pipeline operator that is executing the RTO. This defines the join graph (vertices, edges, and constraints) and also provides access to the AST and related metadata required to execute the join graph.
limit- The limit for the cutoff join.
predicates- The path segment, which must include the target vertex as the last component of the path segment.
constraints- The constraints declared for the join graph (if any). The appropriate constraints will be applied based on the variables which are known to be bound as of the cutoff join for the last vertex in the path segment.
trueiff all vertices in the join graph are incorporated into this path.
sourceSample- The input sample for the cutoff join. When this is a one-step estimation of the cardinality of the edge, then this sample is taken from the
VertexSample. When the edge (vSource, vTarget) extends some
Path, then this is taken from the
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