com.hazelcast.jet.sql.impl.opt.physical.index.IndexResolver Maven / Gradle / Ivy
/*
* Copyright 2024 Hazelcast Inc.
*
* Licensed under the Hazelcast Community License (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://hazelcast.com/hazelcast-community-license
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.jet.sql.impl.opt.physical.index;
import com.hazelcast.shaded.com.google.common.collect.BoundType;
import com.hazelcast.shaded.com.google.common.collect.Iterables;
import com.hazelcast.shaded.com.google.common.collect.Range;
import com.hazelcast.shaded.com.google.common.collect.RangeSet;
import com.hazelcast.config.IndexType;
import com.hazelcast.internal.util.BiTuple;
import com.hazelcast.jet.datamodel.Tuple2;
import com.hazelcast.jet.sql.impl.opt.OptUtils;
import com.hazelcast.jet.sql.impl.opt.logical.FullScanLogicalRel;
import com.hazelcast.jet.sql.impl.opt.physical.IndexScanMapPhysicalRel;
import com.hazelcast.jet.sql.impl.opt.physical.visitor.RexToExpression;
import com.hazelcast.jet.sql.impl.opt.physical.visitor.RexToExpressionVisitor;
import com.hazelcast.jet.sql.impl.schema.HazelcastRelOptTable;
import com.hazelcast.jet.sql.impl.schema.HazelcastTable;
import com.hazelcast.jet.sql.impl.validate.types.HazelcastTypeUtils;
import com.hazelcast.query.impl.ComparableIdentifiedDataSerializable;
import com.hazelcast.query.impl.TypeConverters;
import com.hazelcast.sql.impl.QueryParameterMetadata;
import com.hazelcast.sql.impl.exec.scan.index.IndexCompositeFilter;
import com.hazelcast.sql.impl.exec.scan.index.IndexEqualsFilter;
import com.hazelcast.sql.impl.exec.scan.index.IndexFilter;
import com.hazelcast.sql.impl.exec.scan.index.IndexFilterValue;
import com.hazelcast.sql.impl.exec.scan.index.IndexRangeFilter;
import com.hazelcast.sql.impl.expression.ConstantExpression;
import com.hazelcast.sql.impl.expression.Expression;
import com.hazelcast.sql.impl.plan.node.PlanNodeFieldTypeProvider;
import com.hazelcast.sql.impl.schema.map.MapTableIndex;
import com.hazelcast.sql.impl.type.QueryDataType;
import com.hazelcast.sql.impl.type.QueryDataTypeFamily;
import com.hazelcast.sql.impl.type.QueryDataTypeUtils;
import com.hazelcast.shaded.org.apache.calcite.plan.RelOptTable;
import com.hazelcast.shaded.org.apache.calcite.plan.RelOptUtil;
import com.hazelcast.shaded.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.shaded.org.apache.calcite.rel.RelCollation;
import com.hazelcast.shaded.org.apache.calcite.rel.RelCollationTraitDef;
import com.hazelcast.shaded.org.apache.calcite.rel.RelCollations;
import com.hazelcast.shaded.org.apache.calcite.rel.RelFieldCollation;
import com.hazelcast.shaded.org.apache.calcite.rel.RelNode;
import com.hazelcast.shaded.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.shaded.org.apache.calcite.rex.RexBuilder;
import com.hazelcast.shaded.org.apache.calcite.rex.RexCall;
import com.hazelcast.shaded.org.apache.calcite.rex.RexInputRef;
import com.hazelcast.shaded.org.apache.calcite.rex.RexLiteral;
import com.hazelcast.shaded.org.apache.calcite.rex.RexNode;
import com.hazelcast.shaded.org.apache.calcite.rex.RexUtil;
import com.hazelcast.shaded.org.apache.calcite.sql.SqlKind;
import com.hazelcast.shaded.org.apache.calcite.sql.type.SqlTypeName;
import javax.annotation.Nonnull;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.stream.Collectors;
import static com.hazelcast.config.IndexType.HASH;
import static com.hazelcast.config.IndexType.SORTED;
import static com.hazelcast.jet.impl.util.Util.toList;
import static com.hazelcast.jet.sql.impl.opt.OptUtils.createRelTable;
import static com.hazelcast.jet.sql.impl.opt.OptUtils.getCluster;
import static com.hazelcast.query.impl.CompositeValue.NEGATIVE_INFINITY;
import static com.hazelcast.query.impl.CompositeValue.POSITIVE_INFINITY;
import static com.hazelcast.sql.impl.expression.ConstantExpression.NULL;
import static java.lang.Boolean.FALSE;
import static java.lang.Boolean.TRUE;
import static java.util.Collections.singletonList;
import static com.hazelcast.shaded.org.apache.calcite.rel.RelFieldCollation.Direction;
import static com.hazelcast.shaded.org.apache.calcite.rel.RelFieldCollation.Direction.ASCENDING;
import static com.hazelcast.shaded.org.apache.calcite.rel.RelFieldCollation.Direction.DESCENDING;
/**
* Helper class to resolve indexes.
*/
@SuppressWarnings({"rawtypes", "checkstyle:MethodCount"})
public final class IndexResolver {
private IndexResolver() {
// No-op.
}
/**
* The main entry point for index planning.
*
* Analyzes the filter of the input scan operator, and produces zero, one or more {@link IndexScanMapPhysicalRel}
* operators.
*
* First, the full index scans are created and the covered (prefix-based) scans are excluded.
* Second, the lookups are created and if lookup's collation is equal to the full scan's collation,
* the latter one is excluded.
*
* @param scan scan operator to be analyzed
* @param indexes indexes available on the map being scanned
* @return zero, one or more index scan rels
*/
@SuppressWarnings({"checkstyle:CyclomaticComplexity", "checkstyle:NPathComplexity", "checkstyle:MethodLength"})
public static Collection createIndexScans(FullScanLogicalRel scan, List indexes) {
RexNode filter = OptUtils.extractHazelcastTable(scan).getFilter();
// Filter out unsupported indexes. Only SORTED and HASH indexes are supported.
List supportedIndexes = new ArrayList<>(indexes.size());
Set allIndexedFieldOrdinals = new HashSet<>();
for (MapTableIndex index : indexes) {
if (isIndexSupported(index)) {
supportedIndexes.add(index);
allIndexedFieldOrdinals.addAll(index.getFieldOrdinals());
}
}
// Early return if there are no indexes to consider.
if (supportedIndexes.isEmpty()) {
return Collections.emptyList();
}
List fullScanRels = new ArrayList<>(supportedIndexes.size());
// There is no filter, still generate index scans for
// possible ORDER BY clause on the upper level
for (MapTableIndex index : supportedIndexes) {
if (index.getType() == SORTED) {
// Only for SORTED index create full index scans that might be potentially
// utilized by sorting operator.
List ascs = buildFieldDirections(index, true);
RelNode relAscending = createFullIndexScan(scan, index, ascs, true);
if (relAscending != null) {
fullScanRels.add(relAscending);
RelNode relDescending = replaceCollationDirection(relAscending, DESCENDING);
fullScanRels.add(relDescending);
// For full scan we do not add unsorted scan (unlike in case of filters)
// because it would never be chosen.
//
// Full index scan will never be cheaper than full table scan. This might be
// possible if the index covers all columns in the query. However, we do not
// support this use (index scan always fetches entire entry) and even if we
// did, full scan might still be cheaper. The only use case where full index
// scan makes sense is if order is needed, but in that case, EMPTY collation
// will not be beneficial since [Sort + unsorted index scan] would be worse
// than just sorted index scan.
}
}
}
Map fullScanRelsMap = excludeCoveredCollations(fullScanRels);
if (filter == null) {
// Exclude prefix-based covered index scans
return fullScanRelsMap.values();
}
// Convert expression into CNF. Examples:
// - {a=1 AND b=2} is converted into {a=1}, {b=2}
// - {a=1 OR b=2} is unchanged
List conjunctions = createConjunctiveFilter(filter);
// Create a map from a column to a list of expressions that could be used by indexes.
// For example, for the expression {a>1 AND a<3 AND b=5 AND c>d}, three candidates will be created:
// a -> {>1}, {<3}
// b -> {=5}
Map> candidates = prepareSingleColumnCandidates(
conjunctions,
getCluster(scan).getParameterMetadata(),
allIndexedFieldOrdinals
);
if (candidates.isEmpty()) {
return fullScanRelsMap.values();
}
List rels = new ArrayList<>(supportedIndexes.size());
for (MapTableIndex index : supportedIndexes) {
// Create index scan based on candidates, if possible. Candidates could be merged into more complex
// filters whenever possible.
List ascs = buildFieldDirections(index, true);
RelNode relAscending = createIndexScan(scan, index, conjunctions, candidates, ascs);
if (relAscending != null) {
RelCollation relAscCollation = getCollation(relAscending);
// Exclude a full scan that has the same collation
fullScanRelsMap.remove(relAscCollation);
rels.add(relAscending);
if (relAscCollation.getFieldCollations().size() > 0) {
RelNode relDescending = replaceCollationDirection(relAscending, DESCENDING);
rels.add(relDescending);
RelCollation relDescCollation = getCollation(relDescending);
// Exclude a full scan that has the same collation
fullScanRelsMap.remove(relDescCollation);
// Add variant without enforced collation which may be cheaper
// if the ordering of the result is not required.
rels.add(removeCollation(relAscending));
}
}
}
rels.addAll(fullScanRelsMap.values());
return rels;
}
private static RelCollation getCollation(RelNode rel) {
return rel.getTraitSet().getCollation();
}
/**
* Replaces a direction in the collation trait of the rel
*
* @param rel the rel
* @param direction the collation
* @return the rel with changed collation
*/
private static RelNode replaceCollationDirection(RelNode rel, Direction direction) {
RelCollation collation = rel.getTraitSet().getTrait(RelCollationTraitDef.INSTANCE);
List newFields = new ArrayList<>(collation.getFieldCollations().size());
for (RelFieldCollation fieldCollation : collation.getFieldCollations()) {
RelFieldCollation newFieldCollation = new RelFieldCollation(fieldCollation.getFieldIndex(), direction);
newFields.add(newFieldCollation);
}
RelCollation newCollation = RelCollations.of(newFields);
RelTraitSet traitSet = rel.getTraitSet();
traitSet = OptUtils.traitPlus(traitSet, newCollation);
return rel.copy(traitSet, rel.getInputs());
}
private static RelNode removeCollation(RelNode rel) {
return ((IndexScanMapPhysicalRel) rel).withoutCollation();
}
/**
* Filters out index scans which collation is covered (prefix based) by another index scan in the rels.
*
* @param rels the list of index scans
* @return a filtered out map of collation to rel
*/
@SuppressWarnings("checkstyle:NPathComplexity")
private static Map excludeCoveredCollations(List rels) {
// Order the index scans based on their collation
TreeMap relsTreeMap = new TreeMap<>(RelCollationComparator.INSTANCE);
// Put the rels into the ordered TreeMap
for (RelNode rel : rels) {
relsTreeMap.put(rel.getTraitSet().getTrait(RelCollationTraitDef.INSTANCE), rel);
}
Map resultMap = new HashMap<>();
Map.Entry prevEntry = null;
// Go through the ordered collations and exclude covered ones
for (Map.Entry entry : relsTreeMap.descendingMap().entrySet()) {
RelCollation collation = entry.getKey();
RelNode relNode = entry.getValue();
if (prevEntry == null) {
resultMap.put(collation, relNode);
prevEntry = entry;
} else {
RelCollation prevCollation = prevEntry.getKey();
if (!prevCollation.satisfies(collation)) {
prevEntry = entry;
resultMap.put(collation, relNode);
}
}
}
return resultMap;
}
/**
* Decompose the original scan filter into CNF components.
*/
private static List createConjunctiveFilter(RexNode filter) {
List conjunctions = new ArrayList<>(1);
RelOptUtil.decomposeConjunction(filter, conjunctions);
return conjunctions;
}
/**
* Creates a map from the scan column ordinal to expressions that could be potentially used by indexes created over
* this column.
*
* @param expressions CNF nodes
* @param allIndexedFieldOrdinals ordinals of all columns that have some indexes. Helps to filter out candidates that
* definitely cannot be used earlier.
*/
private static Map> prepareSingleColumnCandidates(
List expressions,
QueryParameterMetadata parameterMetadata,
Set allIndexedFieldOrdinals
) {
Map> res = new HashMap<>();
// Iterate over each CNF component of the expression.
for (RexNode expression : expressions) {
// Try creating a candidate for the expression. The candidate is created iff the expression could be used
// by some index implementation (SORTED, HASH)
IndexComponentCandidate candidate = prepareSingleColumnCandidate(expression, parameterMetadata);
if (candidate == null) {
// Expression cannot be used by any index implementation, skip
continue;
}
if (!allIndexedFieldOrdinals.contains(candidate.getColumnIndex())) {
// Expression could be used by some index implementation, but the map doesn't have indexes using this column
// Therefore, the expression could not be used, skip
continue;
}
// Group candidates by column. E.g. {a>1 AND a<3} is grouped into a single map entry: a->{>1},{<3}
res.computeIfAbsent(candidate.getColumnIndex(), (k) -> new ArrayList<>())
.add(candidate);
}
return res;
}
/**
* Prepares an expression candidate for the given RexNode.
*
* See method body for the details of supported expressions.
*
* @param exp expression
* @return candidate or {@code null} if the expression cannot be used by any index implementation
*/
@SuppressWarnings({"checkstyle:CyclomaticComplexity", "checkstyle:ReturnCount"})
private static IndexComponentCandidate prepareSingleColumnCandidate(
RexNode exp,
QueryParameterMetadata parameterMetadata
) {
SqlKind kind = exp.getKind();
switch (kind) {
case IS_TRUE:
case IS_FALSE:
case IS_NOT_TRUE:
case IS_NOT_FALSE:
// Special case for boolean columns: SELECT * FROM t WHERE f_boolean IS (NOT) TRUE/FALSE.
// Given that boolean column have only 3 values (true, false, null), any such expression could be converted
// to either EQUALS or IN predicates. Examples:
// {f_boolean IS TRUE} -> EQUALS(TRUE)
// {f_boolean IS NOT TRUE} -> IN(EQUALS(FALSE), EQUALS(NULL))
return prepareSingleColumnCandidateBooleanIsTrueFalse(
exp,
removeCastIfPossible(((RexCall) exp).getOperands().get(0)),
kind
);
case INPUT_REF:
// Special case for boolean columns: SELECT * FROM t WHERE f_boolean
// Equivalent to SELECT * FROM t WHERE f_boolean IS TRUE
return prepareSingleColumnCandidateBooleanIsTrueFalse(
exp,
exp,
SqlKind.IS_TRUE
);
case NOT:
// Special case for boolean columns: SELECT * FROM t WHERE NOT f_boolean
// Equivalent to SELECT * FROM t WHERE f_boolean IS FALSE
return prepareSingleColumnCandidateBooleanIsTrueFalse(
exp,
removeCastIfPossible(((RexCall) exp).getOperands().get(0)),
SqlKind.IS_FALSE
);
case IS_NULL:
// Handle SELECT * FROM WHERE column IS NULL.
// Internally it is converted into EQUALS(NULL) filter
return prepareSingleColumnCandidateIsNull(
exp,
removeCastIfPossible(((RexCall) exp).getOperands().get(0))
);
case IS_NOT_NULL:
// Handle SELECT * FROM WHERE column IS NOT NULL.
return prepareSingleColumnCandidateIsNotNull(
exp,
removeCastIfPossible(((RexCall) exp).getOperands().get(0))
);
case GREATER_THAN:
case GREATER_THAN_OR_EQUAL:
case LESS_THAN:
case LESS_THAN_OR_EQUAL:
case EQUALS:
// Handle comparison predicates.
// Converted to either EQUALS or RANGE filter
BiTuple operands = extractComparisonOperands(exp);
return prepareSingleColumnCandidateComparison(
exp,
kind,
operands.element1(),
operands.element2(),
parameterMetadata
);
case SEARCH:
operands = extractComparisonOperands(exp);
return prepareSingleColumnSearchCandidateComparison(
exp,
operands.element1(),
operands.element2()
);
case OR:
// Handle OR/IN predicates. If OR condition refer to only a single column and all comparisons are equality
// comparisons, then composite filter is created. Otherwise null is returned. Examples:
// {a=1 OR a=2} -> IN(EQUALS(1), EQUALS(2))
// {a=1 OR a>2} -> null
// {a=1 OR b=2} -> null
return prepareSingleColumnCandidateOr(
exp,
((RexCall) exp).getOperands(),
parameterMetadata
);
default:
return null;
}
}
/**
* Prepare a candidate for {@code IS (NOT) TRUE/FALSE} expression.
*
* The fundamental observation is that boolean column may have only three values - TRUE/FALSE/NULL. Therefore, every
* such expression could be converted to equivalent equals or IN predicate:
* - IS TRUE -> EQUALS(TRUE)
* - IS FALSE -> EQUALS(FALSE)
* - IS NOT TRUE -> IN(EQUALS(FALSE), EQUALS(NULL))
* - IS NOT FALSE -> IN(EQUALS(TRUE), EQUALS(NULL))
*
* @param exp original expression, e.g. {col IS TRUE}
* @param operand operand, e.g. {col}; CAST must be unwrapped before the method is invoked
* @param kind expression type
* @return candidate or {@code null}
*/
private static IndexComponentCandidate prepareSingleColumnCandidateBooleanIsTrueFalse(
RexNode exp,
RexNode operand,
SqlKind kind
) {
if (operand.getKind() != SqlKind.INPUT_REF) {
// The operand is not a column, e.g. {'true' IS TRUE}, index cannot be used
return null;
}
if (operand.getType().getSqlTypeName() != SqlTypeName.BOOLEAN) {
// The column is not of BOOLEAN type. We should never hit this branch normally. Added here only for safety.
return null;
}
int columnIndex = ((RexInputRef) operand).getIndex();
IndexFilter filter;
switch (kind) {
case IS_TRUE:
filter = new IndexEqualsFilter(new IndexFilterValue(
singletonList(ConstantExpression.TRUE), singletonList(false)
));
break;
case IS_FALSE:
filter = new IndexEqualsFilter(new IndexFilterValue(
singletonList(ConstantExpression.FALSE), singletonList(false)
));
break;
case IS_NOT_TRUE:
filter = new IndexCompositeFilter(
// produce results in ASC order (null first)
new IndexEqualsFilter(new IndexFilterValue(
singletonList(NULL), singletonList(true)
)),
new IndexEqualsFilter(new IndexFilterValue(
singletonList(ConstantExpression.FALSE), singletonList(false)
))
);
break;
default:
assert kind == SqlKind.IS_NOT_FALSE;
filter = new IndexCompositeFilter(
// produce results in ASC order (null first)
new IndexEqualsFilter(new IndexFilterValue(
singletonList(NULL), singletonList(true)
)),
new IndexEqualsFilter(new IndexFilterValue(
singletonList(ConstantExpression.TRUE), singletonList(false)
))
);
}
return new IndexComponentCandidate(exp, columnIndex, filter);
}
/**
* Try creating a candidate filter for the "IS NULL" expression.
*
* Returns the filter EQUALS(null) with "allowNulls-true".
*
* @param exp original expression, e.g. {col IS NULL}
* @param operand operand, e.g. {col}; CAST must be unwrapped before the method is invoked
* @return candidate or {@code null}
*/
private static IndexComponentCandidate prepareSingleColumnCandidateIsNull(RexNode exp, RexNode operand) {
if (operand.getKind() != SqlKind.INPUT_REF) {
// The operand is not a column, e.g. {'literal' IS NULL}, index cannot be used
return null;
}
int columnIndex = ((RexInputRef) operand).getIndex();
QueryDataType type = HazelcastTypeUtils.toHazelcastType(operand.getType());
// Create a value with "allowNulls=true"
IndexFilterValue filterValue = new IndexFilterValue(
singletonList(ConstantExpression.create(null, type)),
singletonList(true)
);
IndexFilter filter = new IndexEqualsFilter(filterValue);
return new IndexComponentCandidate(
exp,
columnIndex,
filter
);
}
/**
* Try creating a candidate filter for the "IS NOT NULL" expression.
*
* Returns the filter RANGE(-inf..+inf) with "allowNulls-false".
*
* @param exp original expression, e.g. {col IS NOT NULL}
* @param operand operand, e.g. {col}; CAST must be unwrapped before the method is invoked
* @return candidate or {@code null}
*/
private static IndexComponentCandidate prepareSingleColumnCandidateIsNotNull(RexNode exp, RexNode operand) {
if (operand.getKind() != SqlKind.INPUT_REF) {
// The operand is not a column, e.g. {'literal' IS NOT NULL}, index cannot be used
return null;
}
int columnIndex = ((RexInputRef) operand).getIndex();
// Create a range scan for entire range (-inf..+inf), range scan does not include nulls
IndexFilter filter = new IndexRangeFilter(null, false, null, false);
return new IndexComponentCandidate(
exp,
columnIndex,
filter
);
}
/**
* Try creating a candidate filter for comparison operator.
*
* @param exp the original expression
* @param kind expression kine (=, >, <, >=, <=)
* @param operand1 the first operand (CAST must be unwrapped before the method is invoked)
* @param operand2 the second operand (CAST must be unwrapped before the method is invoked)
* @param parameterMetadata parameter metadata for expressions like {a>?}
* @return candidate or {@code null}
*/
private static IndexComponentCandidate prepareSingleColumnCandidateComparison(
RexNode exp,
SqlKind kind,
RexNode operand1,
RexNode operand2,
QueryParameterMetadata parameterMetadata
) {
// Normalize operand positions, so that the column is always goes first.
// The condition (kind) is changed accordingly (e.g. ">" to "<").
if (operand1.getKind() != SqlKind.INPUT_REF && operand2.getKind() == SqlKind.INPUT_REF) {
kind = inverseIndexConditionKind(kind);
RexNode tmp = operand1;
operand1 = operand2;
operand2 = tmp;
}
if (operand1.getKind() != SqlKind.INPUT_REF) {
// No columns in the expression, index cannot be used. E.g. {'a' > 'b'}
return null;
}
int columnIndex = ((RexInputRef) operand1).getIndex();
if (!IndexRexVisitor.isValid(operand2)) {
// The second operand cannot be used for index filter because its value possibly row-dependent.
// E.g. {column_a > column_b}.
return null;
}
// Convert the second operand into Hazelcast expression. The expression will be evaluated once before index scan is
// initiated, to construct the proper filter for index lookup.
Expression filterValue = convertToExpression(operand2, parameterMetadata);
if (filterValue == null) {
// The second operand cannot be converted to expression. Do not throw an exception here, just do not use the faulty
// condition for index. The proper exception will be thrown on later stages when attempting to convert Calcite rel
// tree to Hazelcast plan.
return null;
}
// Create the value that will be passed to filters. Not that "allowNulls=false" here, because any NULL in the comparison
// operator never returns "TRUE" and hence always returns an empty result set.
IndexFilterValue filterValue0 = new IndexFilterValue(
singletonList(filterValue),
singletonList(false)
);
IndexFilter filter;
switch (kind) {
case EQUALS:
filter = new IndexEqualsFilter(filterValue0);
break;
case GREATER_THAN:
filter = new IndexRangeFilter(filterValue0, false, null, false);
break;
case GREATER_THAN_OR_EQUAL:
filter = new IndexRangeFilter(filterValue0, true, null, false);
break;
case LESS_THAN:
filter = new IndexRangeFilter(null, false, filterValue0, false);
break;
default:
assert kind == SqlKind.LESS_THAN_OR_EQUAL;
filter = new IndexRangeFilter(null, false, filterValue0, true);
}
return new IndexComponentCandidate(
exp,
columnIndex,
filter
);
}
@SuppressWarnings({"ConstantConditions"})
private static IndexComponentCandidate prepareSingleColumnSearchCandidateComparison(
RexNode exp,
RexNode operand1,
RexNode operand2
) {
// for SARG we expect input reference on the left side, and a (Sarg) literal on the right side
if (operand1.getKind() != SqlKind.INPUT_REF || operand2.getKind() != SqlKind.LITERAL) {
return null;
}
int columnIndex = ((RexInputRef) operand1).getIndex();
RexLiteral literal = (RexLiteral) operand2;
QueryDataType hazelcastType = HazelcastTypeUtils.toHazelcastType(literal.getType());
Tuple2, Boolean> rangeSet = RexToExpression.extractRangeSetAndNullAsFromSearch(literal);
if (rangeSet == null) {
return null;
}
Set> ranges = rangeSet.f0().asRanges();
IndexFilter indexFilter;
if (TRUE.equals(rangeSet.f1())) {
IndexEqualsFilter isNullFilter = new IndexEqualsFilter(new IndexFilterValue(
singletonList(NULL),
singletonList(true)
));
if (ranges.size() == 0) {
indexFilter = isNullFilter;
} else {
List indexFilters = new ArrayList<>(ranges.size() + 1);
indexFilters.add(isNullFilter);
for (Range range : ranges) {
indexFilters.add(createIndexFilterForSingleRange(range, hazelcastType));
}
indexFilter = new IndexCompositeFilter(indexFilters);
}
} else {
if (ranges.size() == 1) {
indexFilter = createIndexFilterForSingleRange(Iterables.getFirst(ranges, null), hazelcastType);
} else {
indexFilter = new IndexCompositeFilter(
toList(ranges, range -> createIndexFilterForSingleRange(range, hazelcastType)));
}
}
return new IndexComponentCandidate(exp, columnIndex, indexFilter);
}
@SuppressWarnings("unchecked")
@Nonnull
private static IndexFilter createIndexFilterForSingleRange(Range range, QueryDataType hazelcastType) {
IndexFilterValue lowerBound0 = null;
// Range doesn't have to have both bounds.
if (range.hasLowerBound()) {
Expression lowerBound = ConstantExpression.create(range.lowerEndpoint(), hazelcastType);
lowerBound0 = new IndexFilterValue(
singletonList(lowerBound),
singletonList(false)
);
if (isSingletonRange(range)) {
return new IndexEqualsFilter(lowerBound0);
}
}
if (range.hasUpperBound()) {
Expression upperBound = ConstantExpression.create(range.upperEndpoint(), hazelcastType);
IndexFilterValue upperBound0 = new IndexFilterValue(
singletonList(upperBound),
singletonList(false)
);
if (lowerBound0 == null) {
return new IndexRangeFilter(null, false, upperBound0, range.upperBoundType() == BoundType.CLOSED);
}
return new IndexRangeFilter(lowerBound0, range.lowerBoundType() == BoundType.CLOSED,
upperBound0, range.upperBoundType() == BoundType.CLOSED);
} else {
assert lowerBound0 != null;
return new IndexRangeFilter(lowerBound0, range.lowerBoundType() == BoundType.CLOSED, null, false);
}
}
private static > boolean isSingletonRange(Range range) {
return range.hasLowerBound() && range.hasUpperBound()
&& range.lowerBoundType() == BoundType.CLOSED
&& range.upperBoundType() == BoundType.CLOSED
&& range.lowerEndpoint().compareTo(range.upperEndpoint()) == 0;
}
private static Expression convertToExpression(RexNode operand, QueryParameterMetadata parameterMetadata) {
try {
RexToExpressionVisitor visitor =
new RexToExpressionVisitor(PlanNodeFieldTypeProvider.FAILING_FIELD_TYPE_PROVIDER, parameterMetadata);
return operand.accept(visitor);
} catch (Exception e) {
return null;
}
}
/**
* Prepare candidate for OR expression if possible.
*
* We support only equality conditions on the same columns. Ranges and conditions on different columns (aka "index joins")
* are not supported.
*
* @param exp the OR expression
* @param nodes components of the OR expression
* @param parameterMetadata parameter metadata
* @return candidate or {code null}
*/
private static IndexComponentCandidate prepareSingleColumnCandidateOr(
RexNode exp,
List nodes,
QueryParameterMetadata parameterMetadata
) {
Integer columnIndex = null;
List filters = new ArrayList<>();
for (RexNode node : nodes) {
IndexComponentCandidate candidate = prepareSingleColumnCandidate(node, parameterMetadata);
if (candidate == null) {
// The component of the OR expression cannot be used by any index implementation
return null;
}
IndexFilter candidateFilter = candidate.getFilter();
// Make sure that all '=' expressions relate to a single column
if (columnIndex == null) {
columnIndex = candidate.getColumnIndex();
} else if (columnIndex != candidate.getColumnIndex()) {
return null;
}
// Flatten. E.g. ((a=1 OR a=2) OR a=3) is parsed into IN(1, 2) and OR(3), that is then flatten into IN(1, 2, 3)
if (candidateFilter instanceof IndexEqualsFilter || candidateFilter instanceof IndexRangeFilter) {
filters.add(candidateFilter);
} else {
filters.addAll(((IndexCompositeFilter) candidateFilter).getFilters());
}
}
assert columnIndex != null;
IndexCompositeFilter inFilter = new IndexCompositeFilter(filters);
return new IndexComponentCandidate(
exp,
columnIndex,
inFilter
);
}
/**
* Create index scan for the given index if possible.
*
* @param scan the original map scan
* @param index index to be considered
* @param conjunctions CNF components of the original map filter
* @param candidates resolved candidates
* @param ascs a list of index field collations
* @return index scan or {@code null}.
*/
public static RelNode createIndexScan(
FullScanLogicalRel scan,
MapTableIndex index,
List conjunctions,
Map> candidates,
List ascs
) {
List filters = new ArrayList<>(index.getFieldOrdinals().size());
// Iterate over every index component from the beginning and try to form a filter to it
for (int i = 0; i < index.getFieldOrdinals().size(); i++) {
int fieldOrdinal = index.getFieldOrdinals().get(i);
QueryDataType fieldConverterType = index.getFieldConverterTypes().get(i);
List fieldCandidates = candidates.get(fieldOrdinal);
if (fieldCandidates == null) {
// No candidates available for the given component, stop.
// Consider the index {a, b, c}. If there is a condition "WHERE a=1 AND c=3", only "a=1" could be
// used for index filter.
break;
}
// Create the filter for the given index component if possible.
// Separate candidates are possibly merged into a single complex filter at this stage.
// Consider the index {a}, and the condition "WHERE a>1 AND a<5". In this case two distinct range candidates
// {>1} and {<5} are combined into a single RANGE filter {>1 AND <5}
IndexComponentFilter filter = IndexComponentFilterResolver.findBestComponentFilter(
index.getType(),
fieldCandidates,
fieldConverterType
);
if (filter == null) {
// Cannot create a filter for the given candidates, stop.
break;
}
filters.add(filter);
if (!(filter.getFilter() instanceof IndexEqualsFilter)) {
// For composite indexes, non-equals condition must always be the last part of the request, otherwise we stop.
// Consider an index SORTED{a,b} and the condition "WHERE a>1 AND b=1". We cannot use both {a>1} and {b=1}
// filters here, because there is no single index request that could return such entries. Therefore, we use only
// {a>1} filter.
break;
}
}
if (filters.isEmpty()) {
// Failed to build any filters. The index cannot be used.
return null;
}
// Now as filters are determined, construct the physical entity.
return createIndexScan(scan, index, conjunctions, filters, ascs);
}
private static IndexScanMapPhysicalRel createIndexScan(
FullScanLogicalRel scan,
MapTableIndex index,
List conjunctions,
List filterDescriptors,
List ascs
) {
// Collect filters and relevant expressions
List filters = new ArrayList<>(filterDescriptors.size());
Set exps = new HashSet<>();
for (IndexComponentFilter filterDescriptor : filterDescriptors) {
filters.add(filterDescriptor.getFilter());
exps.addAll(filterDescriptor.getExpressions());
}
// Construct Calcite expressions.
RexBuilder rexBuilder = scan.getCluster().getRexBuilder();
RexNode exp = RexUtil.composeConjunction(rexBuilder, exps);
List remainderConjunctiveExps = excludeNodes(conjunctions, exps);
RexNode remainderExp =
remainderConjunctiveExps.isEmpty() ? null : RexUtil.composeConjunction(rexBuilder, remainderConjunctiveExps);
// Prepare traits
RelTraitSet traitSet = scan.getTraitSet();
// Make a collation trait
RelCollation relCollation = buildCollationTrait(scan, index, ascs);
traitSet = OptUtils.traitPlus(traitSet, relCollation);
// Prepare table
HazelcastRelOptTable originalRelTable = (HazelcastRelOptTable) scan.getTable();
HazelcastTable originalHazelcastTable = OptUtils.extractHazelcastTable(scan);
RelOptTable newRelTable = createRelTable(
originalRelTable,
originalHazelcastTable.withFilter(null),
scan.getCluster().getTypeFactory()
);
// Try composing the final filter out of the isolated component filters if possible
IndexFilter filter = composeFilter(filters, index.getType(), index.getComponentsCount());
if (filter == null) {
return null;
}
// Construct the scan
return new IndexScanMapPhysicalRel(
scan.getCluster(),
OptUtils.toPhysicalConvention(traitSet),
newRelTable,
index,
filter,
exp,
remainderExp
);
}
/**
* Builds a collation with collation fields re-mapped according to the table projections.
*
* @param scan the logical map scan
* @param index the index
* @param ascs the collation of index fields
* @return the new collation trait
*/
private static RelCollation buildCollationTrait(
FullScanLogicalRel scan,
MapTableIndex index,
List ascs
) {
if (index.getType() != SORTED) {
return RelCollations.of(Collections.emptyList());
}
List fields = new ArrayList<>(index.getFieldOrdinals().size());
HazelcastTable table = OptUtils.extractHazelcastTable(scan);
// Extract those projections that are direct input field references. Only those can be used
// for index access
List fieldProjects = table.getProjects()
.stream().filter(expr -> expr instanceof RexInputRef)
.map(inputRef -> ((RexInputRef) inputRef).getIndex())
.collect(Collectors.toList());
for (int i = 0; i < index.getFieldOrdinals().size(); ++i) {
Integer indexFieldOrdinal = index.getFieldOrdinals().get(i);
int remappedIndexFieldOrdinal = fieldProjects.indexOf(indexFieldOrdinal);
if (remappedIndexFieldOrdinal == -1) {
// The field is not used in the query
break;
}
Direction direction = ascs.get(i) ? ASCENDING : DESCENDING;
RelFieldCollation fieldCollation = new RelFieldCollation(remappedIndexFieldOrdinal, direction);
fields.add(fieldCollation);
}
return RelCollations.of(fields);
}
/**
* Builds a list of all ascending or all descending field directions for the index fields
*
* @param allAscending whether all fields are ascending
* @return the list of field directions
*/
private static List buildFieldDirections(MapTableIndex index, boolean allAscending) {
List ascs = new ArrayList<>(index.getFieldOrdinals().size());
for (int i = 0; i < index.getFieldOrdinals().size(); ++i) {
Boolean asc = allAscending ? TRUE : FALSE;
ascs.add(asc);
}
return ascs;
}
/**
* Creates an index scan without any filter.
*
* @param scan the original scan operator
* @param index available indexes
* @param ascs the collation of index fields
* @param nonEmptyCollation whether to filter out full index scan with no collation
* @return index scan or {@code null}
*/
private static RelNode createFullIndexScan(
FullScanLogicalRel scan,
MapTableIndex index,
List ascs,
boolean nonEmptyCollation
) {
assert isIndexSupported(index);
RexNode scanFilter = OptUtils.extractHazelcastTable(scan).getFilter();
RelTraitSet traitSet = OptUtils.toPhysicalConvention(scan.getTraitSet());
RelCollation relCollation = buildCollationTrait(scan, index, ascs);
if (nonEmptyCollation && relCollation.getFieldCollations().size() == 0) {
// Don't make a full scan with empty collation
return null;
}
traitSet = OptUtils.traitPlus(traitSet, relCollation);
HazelcastRelOptTable originalRelTable = (HazelcastRelOptTable) scan.getTable();
HazelcastTable originalHazelcastTable = OptUtils.extractHazelcastTable(scan);
RelOptTable newRelTable = createRelTable(
originalRelTable.getDelegate().getQualifiedName(),
originalHazelcastTable.withFilter(null),
scan.getCluster().getTypeFactory()
);
return new IndexScanMapPhysicalRel(
scan.getCluster(),
traitSet,
newRelTable,
index,
null,
null,
scanFilter
);
}
/**
* Composes the final filter from the list of single-column filters.
*
* @param filters single-column filters
* @param indexType type of the index
* @param indexComponentsCount number of components in the index
* @return final filter or {@code null} if the filter could not be built for the given index type
*/
private static IndexFilter composeFilter(List filters, IndexType indexType, int indexComponentsCount) {
assert !filters.isEmpty();
if (indexComponentsCount == 1) {
// Non-composite index. Just pick the first filter
assert filters.size() == 1;
IndexFilter res = filters.get(0);
assert !(res instanceof IndexRangeFilter) || indexType == SORTED;
return res;
} else {
// At this point component filters has the form "1=EQUALS, 2=EQUALS, ..., N=EQUALS/RANGE/IN".
// Compose the final filter based on the type of the last resolved filter.
IndexFilter lastFilter = filters.get(filters.size() - 1);
if (lastFilter instanceof IndexEqualsFilter) {
return composeEqualsFilter(filters, (IndexEqualsFilter) lastFilter, indexType, indexComponentsCount);
} else if (lastFilter instanceof IndexCompositeFilter) {
return composeCompositeFilter(filters, (IndexCompositeFilter) lastFilter, indexType, indexComponentsCount);
} else {
assert lastFilter instanceof IndexRangeFilter;
assert indexType == SORTED;
return composeRangeFilter(filters, (IndexRangeFilter) lastFilter, indexType, indexComponentsCount);
}
}
}
/**
* Composes an equality filter from multiple single-column components.
*
* If the number of single-column filters is equal to the number of index components, the resulting filter is a composite
* equality filter.
*
* If the number of single-column filters is less than the number of index components, the resulting filter is a range
* filter, with missing components filled with negative/positive infinities for the left and right bounds respectively.
*
* If the range filter is required, and the target index type is not {@link IndexType#SORTED}, the result is {@code null}.
*
* Examples:
*
* - SORTED(a, b), {a=1, b=2} => EQUALS(1), EQUALS(2)
* - HASH(a, b), {a=1, b=2} => EQUALS(1), EQUALS(2)
* - SORTED(a, b), {a=1} => EQUALS(1), RANGE(INF)
* - HASH(a, b), {a=1} => null
*
*
* @return composite filter or {@code null}
*/
private static IndexFilter composeEqualsFilter(
List filters,
IndexEqualsFilter lastFilter,
IndexType indexType,
int indexComponentsCount
) {
// Flatten all known values.
List components = new ArrayList<>(filters.size());
List allowNulls = new ArrayList<>(filters.size());
fillNonTerminalComponents(filters, components, allowNulls);
components.addAll(lastFilter.getValue().getComponents());
allowNulls.addAll(lastFilter.getValue().getAllowNulls());
if (indexComponentsCount == components.size()) {
// If there is a full match, then leave it as equals filter
return new IndexEqualsFilter(new IndexFilterValue(components, allowNulls));
} else {
// Otherwise convert it to a range request
if (indexType == HASH) {
return null;
}
List fromComponents = components;
List toComponents = new ArrayList<>(components);
List fromAllowNulls = allowNulls;
List toAllowNulls = new ArrayList<>(fromAllowNulls);
addInfiniteRanges(fromComponents, fromAllowNulls, true, toComponents, toAllowNulls, true, indexComponentsCount);
return new IndexRangeFilter(
new IndexFilterValue(fromComponents, fromAllowNulls),
true,
new IndexFilterValue(toComponents, toAllowNulls),
true
);
}
}
/**
* Create the final composite filter from the collection of per-column filters.
*
* Consider the expression {@code {a=1 AND b IN (2,3)}}. After the conversion, the composite filter will be
* {@code {a,b} IN {{1, 2}, {1, 3}}}.
*
* @param filters per-column filters
* @param lastFilter the last composite filter
* @param indexComponentsCount the number of index components
* @return composite filter
*/
private static IndexFilter composeCompositeFilter(
List filters,
IndexCompositeFilter lastFilter,
IndexType indexType,
int indexComponentsCount
) {
List newFilters = new ArrayList<>(lastFilter.getFilters().size());
for (IndexFilter filter : lastFilter.getFilters()) {
if (filter instanceof IndexEqualsFilter) {
IndexFilter newFilter = composeEqualsFilter(filters, (IndexEqualsFilter) filter, indexType, indexComponentsCount);
if (newFilter == null) {
// Cannot create a filter for one of the values of the IN clause. Stop.
return null;
}
newFilters.add(newFilter);
} else if (filter instanceof IndexRangeFilter) {
IndexFilter newFilter = composeRangeFilter(filters, (IndexRangeFilter) filter, indexType, indexComponentsCount);
newFilters.add(newFilter);
}
}
return new IndexCompositeFilter(newFilters);
}
/**
* Create the composite range filter from the given per-column filters.
*
* If the number of per-column filters if less than the number of index components, then infinite ranges are added
* to the missing components.
*
* Consider that we have two per-column filter as input: {@code {a=1}, {b>2 AND b<3}}.
*
* If the index is defined as {@code {a, b}}, then the resulting filter would be {@code {a=1, b>2 AND a=1, b<3}}.
*
* If the index is defined as {@code {a, b, c}}, then the resulting filter would be
* {@code {a=1, b>2, c>NEGATIVE_INFINITY AND a=1, b<3, c filters,
IndexRangeFilter lastFilter,
IndexType indexType,
int componentsCount
) {
if (indexType == HASH) {
return null;
}
// Flatten non-terminal components.
List components = new ArrayList<>(filters.size());
List allowNulls = new ArrayList<>();
fillNonTerminalComponents(filters, components, allowNulls);
// Add value of the current filter.
List fromComponents = components;
List toComponents = new ArrayList<>(components);
List fromAllowNulls = allowNulls;
List toAllowNulls = new ArrayList<>(fromAllowNulls);
if (lastFilter.getFrom() != null) {
fromComponents.add(lastFilter.getFrom().getComponents().get(0));
fromAllowNulls.add(false);
} else {
if (componentsCount == 1) {
fromComponents.add(ConstantExpression.create(NEGATIVE_INFINITY, QueryDataType.OBJECT));
fromAllowNulls.add(false);
} else {
// In composite indexes null values are not stored separately. Therefore, we need to filter them out.
fromComponents.add(ConstantExpression.create(null, QueryDataType.OBJECT));
fromAllowNulls.add(true);
}
}
if (lastFilter.getTo() != null) {
toComponents.add(lastFilter.getTo().getComponents().get(0));
} else {
toComponents.add(ConstantExpression.create(POSITIVE_INFINITY, QueryDataType.OBJECT));
}
toAllowNulls.add(false);
// Fill missing part of the range request.
addInfiniteRanges(
fromComponents,
fromAllowNulls,
lastFilter.isFromInclusive(),
toComponents,
toAllowNulls,
lastFilter.isToInclusive(),
componentsCount
);
return new IndexRangeFilter(
new IndexFilterValue(fromComponents, fromAllowNulls),
lastFilter.isFromInclusive(),
new IndexFilterValue(toComponents, toAllowNulls),
lastFilter.isToInclusive()
);
}
/**
* Given the list of column filters, flatten their expressions and allow-null flags.
*
* The operation is performed for all filters except for the last one, because treatment of the last filter might differ
* depending on the total number of components in the index.
*
* @param filters column filters
* @param components expressions that would form the final filter
* @param allowNulls allow-null collection relevant to components
*/
private static void fillNonTerminalComponents(
List filters,
List components,
List allowNulls
) {
for (int i = 0; i < filters.size() - 1; i++) {
IndexEqualsFilter filter0 = (IndexEqualsFilter) filters.get(i);
IndexFilterValue value = filter0.getValue();
assert value.getComponents().size() == 1;
components.add(value.getComponents().get(0));
allowNulls.add(value.getAllowNulls().get(0));
}
assert components.size() == filters.size() - 1;
assert allowNulls.size() == filters.size() - 1;
}
/**
* Adds infinite ranges to filter components, to match the number of index components.
*
* For example, for the index on {@code (a, b)} and the expression {@code a=1}, the original filter would be
* {@code from={a=1}, to={a=1}}.
*
* Since the index has two components, we need to add infinite ranges to components that do not have explicit filters.
* After the method finishes, the filter would be {@code from={a=1, b=NEGATIVE_INFINITY}, to={a=1, b=POSITIVE_INFINITY}}.
*
* The combination of ranges also depends on the inclusion. For example, {@code {a>1}} yields {@code NEGATIVE_INFINITY}
* for {@code b} on the left side, while {@code {a>=1}} yields {@code POSITIVE_INFINITY}.
*
* @param fromComponents expressions for the "from" part
* @param toComponents expressions for the "to" part
* @param componentsCount the number of components in the index
*/
private static void addInfiniteRanges(
List fromComponents,
List fromAllowNulls,
boolean fromInclusive,
List toComponents,
List toAllowNulls,
boolean toInclusive,
int componentsCount
) {
int count = componentsCount - fromComponents.size();
ComparableIdentifiedDataSerializable leftBound = fromInclusive ? NEGATIVE_INFINITY : POSITIVE_INFINITY;
ComparableIdentifiedDataSerializable toBound = toInclusive ? POSITIVE_INFINITY : NEGATIVE_INFINITY;
for (int i = 0; i < count; i++) {
fromComponents.add(ConstantExpression.create(leftBound, QueryDataType.OBJECT));
toComponents.add(ConstantExpression.create(toBound, QueryDataType.OBJECT));
fromAllowNulls.add(false);
toAllowNulls.add(false);
}
}
/**
* Convert the comparison operator to the opposite operator. E.g. {@code >} becomes {@code <}.
*
* This method is invoked during expression normalization to simplify further processing. E.g. {@code ? < a} is converted
* into {@code a > ?}
*
* @param kind original operator
* @return the opposite operator
*/
private static SqlKind inverseIndexConditionKind(SqlKind kind) {
switch (kind) {
case GREATER_THAN:
return SqlKind.LESS_THAN;
case GREATER_THAN_OR_EQUAL:
return SqlKind.LESS_THAN_OR_EQUAL;
case LESS_THAN:
return SqlKind.GREATER_THAN;
case LESS_THAN_OR_EQUAL:
return SqlKind.GREATER_THAN_OR_EQUAL;
default:
assert kind == SqlKind.EQUALS;
return kind;
}
}
/**
* Checks whether the index could be used by the engine.
*
* At the moment only SORTED and HASH indexes could be used.
*
* @param index the index
* @return {@code true} if the index could be used, {@code false} otherwise
*/
private static boolean isIndexSupported(MapTableIndex index) {
return index.getType() == SORTED || index.getType() == HASH;
}
/**
* Extracts comparison operands, removing CAST when possible.
*
* @param node original comparison node
* @return a pair of operands
*/
private static BiTuple extractComparisonOperands(RexNode node) {
assert node instanceof RexCall;
RexCall node0 = (RexCall) node;
assert node0.getOperands().size() == 2;
RexNode operand1 = node0.getOperands().get(0);
RexNode operand2 = node0.getOperands().get(1);
RexNode normalizedOperand1 = removeCastIfPossible(operand1);
RexNode normalizedOperand2 = removeCastIfPossible(operand2);
return BiTuple.of(normalizedOperand1, normalizedOperand2);
}
/**
* Removes CAST operator from the column expression when possible.
*
* The following expression might be found: {@code CAST(a AS BIGINT) > ?}. This may happen either due to type coercion
* during sql->rel conversion, or due to explicit user request. In the general case, a function applied to the column makes
* usage of the index on that column impossible.
*
* In case of the {@code CAST} operator we may try to remove the CAST, thus relying on internal index converters to
* downcast the other side of the comparison expression. See {@link TypeConverters}.
*
* @param node original node, possibly CAST
* @return original node if there is nothing to unwrap, or the operand of the CAST
*/
@SuppressWarnings("checkstyle:NestedIfDepth")
private static RexNode removeCastIfPossible(RexNode node) {
if (node.getKind() == SqlKind.CAST) {
RexCall node0 = (RexCall) node;
RexNode from = node0.getOperands().get(0);
if (from instanceof RexInputRef) {
RelDataType fromType = from.getType();
RelDataType toType = node0.getType();
if (fromType.equals(toType)) {
// Redundant conversion => unwrap
return from;
}
QueryDataTypeFamily fromFamily = HazelcastTypeUtils.toHazelcastType(fromType).getTypeFamily();
QueryDataTypeFamily toFamily = HazelcastTypeUtils.toHazelcastType(toType).getTypeFamily();
if (QueryDataTypeUtils.isNumeric(fromFamily) && QueryDataTypeUtils.isNumeric(toFamily)) {
// Converting between numeric types
if (toFamily.getPrecedence() > fromFamily.getPrecedence()) {
// Only conversion from smaller type to bigger type could be removed safely. Otherwise the
// overflow error is possible, so we cannot remove the CAST.
return from;
}
}
}
}
return node;
}
private static List excludeNodes(Collection nodes, Set exclusions) {
List res = new ArrayList<>(nodes.size());
for (RexNode node : nodes) {
if (exclusions.contains(node)) {
continue;
}
res.add(node);
}
return res;
}
}