com.hazelcast.org.apache.calcite.rel.metadata.RelMdUniqueKeys Maven / Gradle / Ivy
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* 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.
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package com.hazelcast.org.apache.calcite.rel.metadata;
import com.hazelcast.org.apache.calcite.linq4j.Linq4j;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.SingleRel;
import com.hazelcast.org.apache.calcite.rel.core.Aggregate;
import com.hazelcast.org.apache.calcite.rel.core.Calc;
import com.hazelcast.org.apache.calcite.rel.core.Correlate;
import com.hazelcast.org.apache.calcite.rel.core.Filter;
import com.hazelcast.org.apache.calcite.rel.core.Intersect;
import com.hazelcast.org.apache.calcite.rel.core.Join;
import com.hazelcast.org.apache.calcite.rel.core.JoinInfo;
import com.hazelcast.org.apache.calcite.rel.core.Minus;
import com.hazelcast.org.apache.calcite.rel.core.Project;
import com.hazelcast.org.apache.calcite.rel.core.Sort;
import com.hazelcast.org.apache.calcite.rel.core.TableModify;
import com.hazelcast.org.apache.calcite.rel.core.TableScan;
import com.hazelcast.org.apache.calcite.rel.core.Union;
import com.hazelcast.org.apache.calcite.rex.RexInputRef;
import com.hazelcast.org.apache.calcite.rex.RexNode;
import com.hazelcast.org.apache.calcite.rex.RexProgram;
import com.hazelcast.org.apache.calcite.util.ImmutableBitSet;
import com.hazelcast.org.apache.calcite.util.Util;
import com.hazelcast.com.google.common.collect.ImmutableMultimap;
import com.hazelcast.com.google.common.collect.ImmutableSet;
import com.hazelcast.com.google.common.collect.Maps;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import static java.util.Objects.requireNonNull;
/**
* RelMdUniqueKeys supplies a default implementation of
* {@link RelMetadataQuery#getUniqueKeys} for the standard logical algebra.
*/
public class RelMdUniqueKeys
implements MetadataHandler {
public static final RelMetadataProvider SOURCE =
ReflectiveRelMetadataProvider.reflectiveSource(
new RelMdUniqueKeys(), BuiltInMetadata.UniqueKeys.Handler.class);
//~ Constructors -----------------------------------------------------------
private RelMdUniqueKeys() {}
//~ Methods ----------------------------------------------------------------
@Override public MetadataDef getDef() {
return BuiltInMetadata.UniqueKeys.DEF;
}
public @Nullable Set getUniqueKeys(Filter rel, RelMetadataQuery mq,
boolean ignoreNulls) {
return mq.getUniqueKeys(rel.getInput(), ignoreNulls);
}
public @Nullable Set getUniqueKeys(Sort rel, RelMetadataQuery mq,
boolean ignoreNulls) {
return mq.getUniqueKeys(rel.getInput(), ignoreNulls);
}
public @Nullable Set getUniqueKeys(Correlate rel, RelMetadataQuery mq,
boolean ignoreNulls) {
return mq.getUniqueKeys(rel.getLeft(), ignoreNulls);
}
public @Nullable Set getUniqueKeys(TableModify rel, RelMetadataQuery mq,
boolean ignoreNulls) {
return mq.getUniqueKeys(rel.getInput(), ignoreNulls);
}
public Set getUniqueKeys(Project rel, RelMetadataQuery mq,
boolean ignoreNulls) {
return getProjectUniqueKeys(rel, mq, ignoreNulls, rel.getProjects());
}
public @Nullable Set getUniqueKeys(Calc rel, RelMetadataQuery mq,
boolean ignoreNulls) {
RexProgram program = rel.getProgram();
return getProjectUniqueKeys(rel, mq, ignoreNulls,
Util.transform(program.getProjectList(), program::expandLocalRef));
}
private static Set getProjectUniqueKeys(SingleRel rel, RelMetadataQuery mq,
boolean ignoreNulls, List projExprs) {
// LogicalProject maps a set of rows to a different set;
// Without knowledge of the mapping function(whether it
// preserves uniqueness), it is only safe to derive uniqueness
// info from the child of a project when the mapping is f(a) => a.
//
// Further more, the unique bitset coming from the child needs
// to be mapped to match the output of the project.
// Single input can be mapped to multiple outputs
ImmutableMultimap.Builder inToOutPosBuilder = ImmutableMultimap.builder();
ImmutableBitSet.Builder mappedInColumnsBuilder = ImmutableBitSet.builder();
// Build an input to output position map.
for (int i = 0; i < projExprs.size(); i++) {
RexNode projExpr = projExprs.get(i);
if (projExpr instanceof RexInputRef) {
int inputIndex = ((RexInputRef) projExpr).getIndex();
inToOutPosBuilder.put(inputIndex, i);
mappedInColumnsBuilder.set(inputIndex);
}
}
ImmutableBitSet inColumnsUsed = mappedInColumnsBuilder.build();
if (inColumnsUsed.isEmpty()) {
// if there's no RexInputRef in the projected expressions
// return empty set.
return ImmutableSet.of();
}
Set childUniqueKeySet =
mq.getUniqueKeys(rel.getInput(), ignoreNulls);
if (childUniqueKeySet == null) {
return ImmutableSet.of();
}
Map mapInToOutPos =
Maps.transformValues(inToOutPosBuilder.build().asMap(), ImmutableBitSet::of);
ImmutableSet.Builder resultBuilder = ImmutableSet.builder();
// Now add to the projUniqueKeySet the child keys that are fully
// projected.
for (ImmutableBitSet colMask : childUniqueKeySet) {
if (!inColumnsUsed.contains(colMask)) {
// colMask contains a column that is not projected as RexInput => the key is not unique
continue;
}
// colMask is mapped to output project, however, the column can be mapped more than once:
// select id, id, id, unique2, unique2
// the resulting unique keys would be {{0},{3}}, {{0},{4}}, {{0},{1},{4}}, ...
Iterable> product = Linq4j.product(
Util.transform(colMask,
in -> Util.filter(
requireNonNull(mapInToOutPos.get(in),
() -> "no entry for column " + in + " in mapInToOutPos: " + mapInToOutPos)
.powerSet(), bs -> !bs.isEmpty())));
resultBuilder.addAll(Util.transform(product, ImmutableBitSet::union));
}
return resultBuilder.build();
}
public @Nullable Set getUniqueKeys(Join rel, RelMetadataQuery mq,
boolean ignoreNulls) {
if (!rel.getJoinType().projectsRight()) {
// only return the unique keys from the LHS since a semijoin only
// returns the LHS
return mq.getUniqueKeys(rel.getLeft(), ignoreNulls);
}
final RelNode left = rel.getLeft();
final RelNode right = rel.getRight();
// first add the different combinations of concatenated unique keys
// from the left and the right, adjusting the right hand side keys to
// reflect the addition of the left hand side
//
// NOTE zfong 12/18/06 - If the number of tables in a join is large,
// the number of combinations of unique key sets will explode. If
// that is undesirable, use RelMetadataQuery.areColumnsUnique() as
// an alternative way of getting unique key information.
final Set retSet = new HashSet<>();
final Set leftSet = mq.getUniqueKeys(left, ignoreNulls);
Set rightSet = null;
final Set tmpRightSet = mq.getUniqueKeys(right, ignoreNulls);
int nFieldsOnLeft = left.getRowType().getFieldCount();
if (tmpRightSet != null) {
rightSet = new HashSet<>();
for (ImmutableBitSet colMask : tmpRightSet) {
ImmutableBitSet.Builder tmpMask = ImmutableBitSet.builder();
for (int bit : colMask) {
tmpMask.set(bit + nFieldsOnLeft);
}
rightSet.add(tmpMask.build());
}
if (leftSet != null) {
for (ImmutableBitSet colMaskRight : rightSet) {
for (ImmutableBitSet colMaskLeft : leftSet) {
retSet.add(colMaskLeft.union(colMaskRight));
}
}
}
}
// locate the columns that participate in equijoins
final JoinInfo joinInfo = rel.analyzeCondition();
// determine if either or both the LHS and RHS are unique on the
// equijoin columns
final Boolean leftUnique =
mq.areColumnsUnique(left, joinInfo.leftSet(), ignoreNulls);
final Boolean rightUnique =
mq.areColumnsUnique(right, joinInfo.rightSet(), ignoreNulls);
// if the right hand side is unique on its equijoin columns, then we can
// add the unique keys from left if the left hand side is not null
// generating
if ((rightUnique != null)
&& rightUnique
&& (leftSet != null)
&& !rel.getJoinType().generatesNullsOnLeft()) {
retSet.addAll(leftSet);
}
// same as above except left and right are reversed
if ((leftUnique != null)
&& leftUnique
&& (rightSet != null)
&& !rel.getJoinType().generatesNullsOnRight()) {
retSet.addAll(rightSet);
}
return retSet;
}
public Set getUniqueKeys(Aggregate rel, RelMetadataQuery mq,
boolean ignoreNulls) {
if (Aggregate.isSimple(rel)) {
final ImmutableBitSet groupKeys = rel.getGroupSet();
final Set inputUniqueKeys = mq
.getUniqueKeys(rel.getInput(), ignoreNulls);
if (inputUniqueKeys == null) {
return ImmutableSet.of(groupKeys);
}
// Try to find more precise unique keys.
final Set preciseUniqueKeys = inputUniqueKeys.stream()
.filter(groupKeys::contains).collect(Collectors.toSet());
return preciseUniqueKeys.isEmpty() ? ImmutableSet.of(groupKeys) : preciseUniqueKeys;
} else if (ignoreNulls) {
// group by keys form a unique key
return ImmutableSet.of(rel.getGroupSet());
} else {
// If the aggregate has grouping sets, all group by keys might be null which means group by
// keys do not form a unique key.
return ImmutableSet.of();
}
}
public Set getUniqueKeys(Union rel, RelMetadataQuery mq,
boolean ignoreNulls) {
if (!rel.all) {
return ImmutableSet.of(
ImmutableBitSet.range(rel.getRowType().getFieldCount()));
}
return ImmutableSet.of();
}
/**
* Any unique key of any input of Intersect is an unique key of the Intersect.
*/
public Set getUniqueKeys(Intersect rel,
RelMetadataQuery mq, boolean ignoreNulls) {
ImmutableSet.Builder keys = new ImmutableSet.Builder<>();
for (RelNode input : rel.getInputs()) {
Set uniqueKeys = mq.getUniqueKeys(input, ignoreNulls);
if (uniqueKeys != null) {
keys.addAll(uniqueKeys);
}
}
ImmutableSet uniqueKeys = keys.build();
if (!uniqueKeys.isEmpty()) {
return uniqueKeys;
}
if (!rel.all) {
return ImmutableSet.of(
ImmutableBitSet.range(rel.getRowType().getFieldCount()));
}
return ImmutableSet.of();
}
/**
* The unique keys of Minus are precisely the unique keys of its first input.
*/
public Set getUniqueKeys(Minus rel,
RelMetadataQuery mq, boolean ignoreNulls) {
Set uniqueKeys = mq.getUniqueKeys(rel.getInput(0), ignoreNulls);
if (uniqueKeys != null) {
return uniqueKeys;
}
if (!rel.all) {
return ImmutableSet.of(
ImmutableBitSet.range(rel.getRowType().getFieldCount()));
}
return ImmutableSet.of();
}
public @Nullable Set getUniqueKeys(TableScan rel, RelMetadataQuery mq,
boolean ignoreNulls) {
final List keys = rel.getTable().getKeys();
if (keys == null) {
return null;
}
for (ImmutableBitSet key : keys) {
assert rel.getTable().isKey(key);
}
return ImmutableSet.copyOf(keys);
}
// Catch-all rule when none of the others apply.
public @Nullable Set getUniqueKeys(RelNode rel, RelMetadataQuery mq,
boolean ignoreNulls) {
// no information available
return null;
}
}
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