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

Class BeamSortRel

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Sort

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

All Implemented Interfaces:

java.lang.Cloneable, BeamRelNode, org.apache.calcite.plan.RelOptNode, org.apache.calcite.rel.RelNode

public class BeamSortRel
extends org.apache.calcite.rel.core.Sort
implements BeamRelNode

BeamRelNode to replace a Sort node.

Since Beam does not fully supported global sort we are using Top to implement the Sort algebra. The following types of ORDER BY are supported:

 select * from t order by id desc limit 10;
 select * from t order by id desc limit 10 offset 5;
 

but Order BY without a limit is NOT supported:

 select * from t order by id desc
 

Constraints

• Due to the constraints of Top, the result of a `ORDER BY LIMIT` must fit into the memory of a single machine.
• Since `WINDOW`(HOP, TUMBLE, SESSION etc) is always associated with `GroupBy`, it does not make much sense to use `ORDER BY` with `WINDOW`.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.rel.RelNode

org.apache.calcite.rel.RelNode.Context

Field Summary

Fields inherited from class org.apache.calcite.rel.core.Sort

collation, fetch, fieldExps, offset

Fields inherited from class org.apache.calcite.rel.SingleRel

input

Fields inherited from class org.apache.calcite.rel.AbstractRelNode

digest, id, rowType, traitSet

Constructor Summary

Constructors

Constructor and Description
BeamSortRel(org.apache.calcite.plan.RelOptCluster cluster, org.apache.calcite.plan.RelTraitSet traits, org.apache.calcite.rel.RelNode child, org.apache.calcite.rel.RelCollation collation, org.apache.calcite.rex.RexNode offset, org.apache.calcite.rex.RexNode fetch)

Method Summary

Modifier and Type	Method and Description
PTransform<PCollectionList<Row>,PCollection<Row>>	buildPTransform()
org.apache.calcite.rel.core.Sort	copy(org.apache.calcite.plan.RelTraitSet traitSet, org.apache.calcite.rel.RelNode newInput, org.apache.calcite.rel.RelCollation newCollation, org.apache.calcite.rex.RexNode offset, org.apache.calcite.rex.RexNode fetch)
int	getCount()
boolean	isLimitOnly()

Methods inherited from class org.apache.calcite.rel.core.Sort

accept, computeSelfCost, copy, copy, explainTerms, getChildExps, getCollation, getCollationList

Methods inherited from class org.apache.calcite.rel.SingleRel

childrenAccept, deriveRowType, estimateRowCount, getInput, getInputs, replaceInput

Methods inherited from class org.apache.calcite.rel.AbstractRelNode

accept, collectVariablesSet, collectVariablesUsed, computeDigest, computeSelfCost, explain, getCluster, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getQuery, getRelTypeName, getRows, getRowType, getTable, getTraitSet, getVariablesSet, getVariablesStopped, isDistinct, isKey, isValid, isValid, metadata, onRegister, recomputeDigest, register, sole, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.beam.sdk.extensions.sql.impl.rel.BeamRelNode

getPCollectionInputs, getPipelineOptions, isBounded

Methods inherited from interface org.apache.calcite.rel.RelNode

accept, accept, childrenAccept, collectVariablesSet, collectVariablesUsed, computeSelfCost, computeSelfCost, copy, estimateRowCount, explain, getChildExps, getCollationList, getConvention, getCorrelVariable, getExpectedInputRowType, getInput, getInputs, getQuery, getRelTypeName, getRows, getRowType, getTable, getVariablesSet, getVariablesStopped, isDistinct, isKey, isValid, isValid, metadata, onRegister, recomputeDigest, register, replaceInput

Methods inherited from interface org.apache.calcite.plan.RelOptNode

getCluster, getDescription, getDigest, getId, getTraitSet

Constructor Detail

BeamSortRel

public BeamSortRel(org.apache.calcite.plan.RelOptCluster cluster,
                   org.apache.calcite.plan.RelTraitSet traits,
                   org.apache.calcite.rel.RelNode child,
                   org.apache.calcite.rel.RelCollation collation,
                   org.apache.calcite.rex.RexNode offset,
                   org.apache.calcite.rex.RexNode fetch)

Method Detail

isLimitOnly

public boolean isLimitOnly()

getCount

public int getCount()

buildPTransform

public PTransform<PCollectionList<Row>,PCollection<Row>> buildPTransform()

Specified by:

buildPTransform in interface BeamRelNode

copy

public org.apache.calcite.rel.core.Sort copy(org.apache.calcite.plan.RelTraitSet traitSet,
                                             org.apache.calcite.rel.RelNode newInput,
                                             org.apache.calcite.rel.RelCollation newCollation,
                                             org.apache.calcite.rex.RexNode offset,
                                             org.apache.calcite.rex.RexNode fetch)

Specified by:

copy in class org.apache.calcite.rel.core.Sort