com.facebook.presto.sql.planner.iterative.rule.PruneIndexSourceColumns.java Source code

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Here is the source code for com.facebook.presto.sql.planner.iterative.rule.PruneIndexSourceColumns.java

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/*
 * Licensed 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 com.facebook.presto.sql.planner.iterative.rule;

import com.facebook.presto.Session;
import com.facebook.presto.matching.Pattern;
import com.facebook.presto.spi.ColumnHandle;
import com.facebook.presto.spi.predicate.TupleDomain;
import com.facebook.presto.sql.planner.PlanNodeIdAllocator;
import com.facebook.presto.sql.planner.Symbol;
import com.facebook.presto.sql.planner.SymbolAllocator;
import com.facebook.presto.sql.planner.iterative.Lookup;
import com.facebook.presto.sql.planner.iterative.Rule;
import com.facebook.presto.sql.planner.plan.IndexSourceNode;
import com.facebook.presto.sql.planner.plan.PlanNode;
import com.facebook.presto.sql.planner.plan.ProjectNode;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Maps;

import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;

import static com.facebook.presto.sql.planner.iterative.rule.Util.pruneInputs;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.ImmutableSet.toImmutableSet;

public class PruneIndexSourceColumns implements Rule {
    private static final Pattern PATTERN = Pattern.typeOf(ProjectNode.class);

    @Override
    public Pattern getPattern() {
        return PATTERN;
    }

    @Override
    public Optional<PlanNode> apply(PlanNode node, Lookup lookup, PlanNodeIdAllocator idAllocator,
            SymbolAllocator symbolAllocator, Session session) {
        ProjectNode parent = (ProjectNode) node;

        PlanNode source = lookup.resolve(parent.getSource());
        if (!(source instanceof IndexSourceNode)) {
            return Optional.empty();
        }

        IndexSourceNode indexSourceNode = (IndexSourceNode) source;

        Optional<Set<Symbol>> prunedIndexSourceOutputs = pruneInputs(indexSourceNode.getOutputSymbols(),
                parent.getAssignments().getExpressions());
        if (!prunedIndexSourceOutputs.isPresent()) {
            return Optional.empty();
        }

        Set<Symbol> newLookupSymbols = indexSourceNode.getLookupSymbols().stream()
                .filter(prunedIndexSourceOutputs.get()::contains).collect(toImmutableSet());

        Map<Symbol, ColumnHandle> newAssignments = Maps.filterEntries(indexSourceNode.getAssignments(),
                entry -> prunedIndexSourceOutputs.get().contains(entry.getKey())
                        || tupleDomainReferencesColumnHandle(indexSourceNode.getEffectiveTupleDomain(),
                                entry.getValue()));

        List<Symbol> prunedIndexSourceOutputList = indexSourceNode.getOutputSymbols().stream()
                .filter(prunedIndexSourceOutputs.get()::contains).collect(toImmutableList());

        return Optional.of(parent.replaceChildren(
                ImmutableList.of(new IndexSourceNode(indexSourceNode.getId(), indexSourceNode.getIndexHandle(),
                        indexSourceNode.getTableHandle(), indexSourceNode.getLayout(), newLookupSymbols,
                        prunedIndexSourceOutputList, newAssignments, indexSourceNode.getEffectiveTupleDomain()))));
    }

    private static boolean tupleDomainReferencesColumnHandle(TupleDomain<ColumnHandle> tupleDomain,
            ColumnHandle columnHandle) {
        return tupleDomain.getDomains().map(domains -> domains.containsKey(columnHandle)).orElse(false);
    }
}