[
https://issues.apache.org/jira/browse/BEAM-4167?focusedWorklogId=104912&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-104912
]
ASF GitHub Bot logged work on BEAM-4167:
----------------------------------------
Author: ASF GitHub Bot
Created on: 23/May/18 00:46
Start Date: 23/May/18 00:46
Worklog Time Spent: 10m
Work Description: kennknowles commented on a change in pull request
#5428: [BEAM-4167] Implement UNNEST
URL: https://github.com/apache/beam/pull/5428#discussion_r190095340
##########
File path:
sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamUnnestRel.java
##########
@@ -0,0 +1,157 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.extensions.sql.impl.rel;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkState;
+
+import com.google.common.collect.ImmutableMap;
+import java.util.List;
+import
org.apache.beam.sdk.extensions.sql.impl.interpreter.BeamSqlExpressionExecutor;
+import org.apache.beam.sdk.extensions.sql.impl.interpreter.BeamSqlFnExecutor;
+import org.apache.beam.sdk.extensions.sql.impl.schema.BeamTableUtils;
+import org.apache.beam.sdk.extensions.sql.impl.utils.CalciteUtils;
+import org.apache.beam.sdk.schemas.Schema;
+import org.apache.beam.sdk.transforms.DoFn;
+import org.apache.beam.sdk.transforms.PTransform;
+import org.apache.beam.sdk.transforms.ParDo;
+import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
+import org.apache.beam.sdk.values.PCollection;
+import org.apache.beam.sdk.values.PCollectionTuple;
+import org.apache.beam.sdk.values.Row;
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.plan.RelTraitSet;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.core.Correlate;
+import org.apache.calcite.rel.core.CorrelationId;
+import org.apache.calcite.rel.core.Uncollect;
+import org.apache.calcite.sql.SemiJoinType;
+import org.apache.calcite.util.ImmutableBitSet;
+
+/**
+ * {@link BeamRelNode} to implement UNNEST, supporting specifically only
{@link Correlate} with
+ * {@link Uncollect}.
+ */
+public class BeamUnnestRel extends Correlate implements BeamRelNode {
+
+ public BeamUnnestRel(
+ RelOptCluster cluster,
+ RelTraitSet traits,
+ RelNode left,
+ RelNode right,
+ CorrelationId correlationId,
+ ImmutableBitSet requiredColumns,
+ SemiJoinType joinType) {
+ super(cluster, traits, left, right, correlationId, requiredColumns,
joinType);
+ }
+
+ @Override
+ public PTransform<PCollectionTuple, PCollection<Row>> toPTransform() {
+ return new Transform();
+ }
+
+ @Override
+ public Correlate copy(
+ RelTraitSet relTraitSet,
+ RelNode left,
+ RelNode right,
+ CorrelationId correlationId,
+ ImmutableBitSet requireColumns,
+ SemiJoinType joinType) {
+ return new BeamUnnestRel(
+ getCluster(), relTraitSet, left, right, correlationId,
requiredColumns, joinType);
+ }
+
+ private class Transform extends PTransform<PCollectionTuple,
PCollection<Row>> {
+ @Override
+ public PCollection<Row> expand(PCollectionTuple inputPCollections) {
+ String stageName = BeamSqlRelUtils.getStageName(BeamUnnestRel.this);
+
+ // The set of rows where we run the correlated unnest for each row
+ PCollection<Row> outer =
+
inputPCollections.apply(BeamSqlRelUtils.getBeamRelInput(left).toPTransform());
+
+ // The correlated subquery
+ BeamUncollectRel uncollect = (BeamUncollectRel)
BeamSqlRelUtils.getBeamRelInput(right);
+ Schema innerSchema = CalciteUtils.toBeamSchema(uncollect.getRowType());
+ checkArgument(
+ innerSchema.getFieldCount() == 1, "Can only UNNEST a single column",
getClass());
+
+ BeamSqlExpressionExecutor expr =
+ new
BeamSqlFnExecutor(BeamSqlRelUtils.getBeamRelInput(uncollect.getInput()));
+
+ Schema joinedSchema = CalciteUtils.toBeamSchema(rowType);
+
+ return outer
+ .apply(
+ stageName,
+ ParDo.of(
+ new UnnestFn(correlationId.getId(), expr, joinedSchema,
innerSchema.getField(0))))
+ .setCoder(joinedSchema.getRowCoder());
+ }
+ }
+
+ private static class UnnestFn extends DoFn<Row, Row> {
+
+ /** The expression that should return an iterable to be uncollected. */
+ private final BeamSqlExpressionExecutor expr;
+ private final int correlationId;
+ private final Schema outputSchema;
+ private final Schema.Field innerField;
+
+ private UnnestFn(
+ int correlationId, BeamSqlExpressionExecutor expr, Schema
outputSchema, Schema.Field innerField) {
+ this.correlationId = correlationId;
+ this.expr = expr;
+ this.outputSchema = outputSchema;
+ this.innerField = innerField;
+ }
+
+ @ProcessElement
+ public void process(@Element Row row, BoundedWindow window,
OutputReceiver<Row> out) {
+
+ List<Object> rawValues = expr.execute(row, window,
ImmutableMap.of(correlationId, row));
+
+ checkState(
+ rawValues.size() == 1,
+ "%s expression to unnest %s resulted in more than one column",
+ getClass(),
+ expr);
+
+ checkState(
+ rawValues.get(0) instanceof Iterable,
+ "%s expression to unnest %s not iterable",
+ getClass(),
+ expr);
+
+ for (Object uncollectedValue : (Iterable) rawValues.get(0)) {
Review comment:
@akedin this line is where the `MULTISET` value is used.
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Issue Time Tracking
-------------------
Worklog Id: (was: 104912)
Time Spent: 2.5h (was: 2h 20m)
> Implement UNNEST
> ----------------
>
> Key: BEAM-4167
> URL: https://issues.apache.org/jira/browse/BEAM-4167
> Project: Beam
> Issue Type: New Feature
> Components: dsl-sql
> Reporter: Anton Kedin
> Assignee: Kenneth Knowles
> Priority: Major
> Time Spent: 2.5h
> Remaining Estimate: 0h
>
> We need to be able to convert collections to relations in the query to
> perform any meaningful operations on them.
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