org.apache.beam.sdk.extensions.sql.impl.rel

Class BeamJoinRel

java.lang.Object

Join

org.apache.beam.sdk.extensions.sql.impl.rel.BeamJoinRel

All Implemented Interfaces:

BeamRelNode

public class BeamJoinRel
extends Join
implements BeamRelNode

BeamRelNode to replace a Join node.

Support for join can be categorized into 3 cases:

• BoundedTable JOIN BoundedTable
• UnboundedTable JOIN UnboundedTable
• BoundedTable JOIN UnboundedTable

For the first two cases, a standard join is utilized as long as the windowFn of the both sides match.

For the third case, sideInput is utilized to implement the join, so there are some constraints:

• FULL OUTER JOIN is not supported.
• If it's a LEFT OUTER JOIN, the unbounded table should on the left side.
• If it's a RIGHT OUTER JOIN, the unbounded table should on the right side.

There are also some general constraints:

• Only equi-join is supported.
• CROSS JOIN is not supported.

Constructor Summary

Constructors

Constructor and Description
BeamJoinRel(BeamSqlEnv sqlEnv, RelOptCluster cluster, RelTraitSet traits, RelNode left, RelNode right, RexNode condition, java.util.Set<CorrelationId> variablesSet, JoinRelType joinType)

Method Summary

Modifier and Type	Method and Description
Join	copy(RelTraitSet traitSet, RexNode conditionExpr, RelNode left, RelNode right, JoinRelType joinType, boolean semiJoinDone)
PCollection<Row>	sideInputJoin(PCollection<KV<Row,Row>> extractedLeftRows, PCollection<KV<Row,Row>> extractedRightRows, Row leftNullRow, Row rightNullRow)
PTransform<PCollectionTuple,PCollection<Row>>	toPTransform() A BeamRelNode is a recursive structure, the BeamQueryPlanner visits it with a DFS(Depth-First-Search) algorithm.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BeamJoinRel

public BeamJoinRel(BeamSqlEnv sqlEnv,
                   RelOptCluster cluster,
                   RelTraitSet traits,
                   RelNode left,
                   RelNode right,
                   RexNode condition,
                   java.util.Set<CorrelationId> variablesSet,
                   JoinRelType joinType)

Method Detail

copy

public Join copy(RelTraitSet traitSet,
                 RexNode conditionExpr,
                 RelNode left,
                 RelNode right,
                 JoinRelType joinType,
                 boolean semiJoinDone)

toPTransform

public PTransform<PCollectionTuple,PCollection<Row>> toPTransform()

Description copied from interface: BeamRelNode

A BeamRelNode is a recursive structure, the BeamQueryPlanner visits it with a DFS(Depth-First-Search) algorithm.

Specified by:

toPTransform in interface BeamRelNode

sideInputJoin

public PCollection<Row> sideInputJoin(PCollection<KV<Row,Row>> extractedLeftRows,
                                      PCollection<KV<Row,Row>> extractedRightRows,
                                      Row leftNullRow,
                                      Row rightNullRow)