Java tutorial
/* * Druid - a distributed column store. * Copyright 2012 - 2015 Metamarkets Group Inc. * * 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 io.druid.query.metadata; import com.google.common.base.Function; import com.google.common.base.Throwables; import com.google.common.collect.Maps; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.ListeningExecutorService; import com.google.common.util.concurrent.MoreExecutors; import com.google.inject.Inject; import com.metamx.common.guava.Sequence; import com.metamx.common.guava.Sequences; import com.metamx.common.logger.Logger; import io.druid.query.AbstractPrioritizedCallable; import io.druid.query.ConcatQueryRunner; import io.druid.query.Query; import io.druid.query.QueryContextKeys; import io.druid.query.QueryInterruptedException; import io.druid.query.QueryRunner; import io.druid.query.QueryRunnerFactory; import io.druid.query.QueryToolChest; import io.druid.query.QueryWatcher; import io.druid.query.metadata.metadata.ColumnAnalysis; import io.druid.query.metadata.metadata.ColumnIncluderator; import io.druid.query.metadata.metadata.SegmentAnalysis; import io.druid.query.metadata.metadata.SegmentMetadataQuery; import io.druid.segment.QueryableIndex; import io.druid.segment.Segment; import io.druid.segment.StorageAdapter; import java.util.ArrayList; import java.util.Arrays; import java.util.Map; import java.util.concurrent.CancellationException; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorService; import java.util.concurrent.TimeUnit; import java.util.concurrent.TimeoutException; public class SegmentMetadataQueryRunnerFactory implements QueryRunnerFactory<SegmentAnalysis, SegmentMetadataQuery> { private static final SegmentAnalyzer analyzer = new SegmentAnalyzer(); private static final Logger log = new Logger(SegmentMetadataQueryRunnerFactory.class); private final SegmentMetadataQueryQueryToolChest toolChest; private final QueryWatcher queryWatcher; @Inject public SegmentMetadataQueryRunnerFactory(SegmentMetadataQueryQueryToolChest toolChest, QueryWatcher queryWatcher) { this.toolChest = toolChest; this.queryWatcher = queryWatcher; } @Override public QueryRunner<SegmentAnalysis> createRunner(final Segment segment) { return new QueryRunner<SegmentAnalysis>() { @Override public Sequence<SegmentAnalysis> run(Query<SegmentAnalysis> inQ, Map<String, Object> responseContext) { SegmentMetadataQuery query = (SegmentMetadataQuery) inQ; final QueryableIndex index = segment.asQueryableIndex(); final Map<String, ColumnAnalysis> analyzedColumns; final int numRows; long totalSize = 0; if (index == null) { // IncrementalIndexSegments (used by in-memory hydrants in the realtime service) do not have a QueryableIndex StorageAdapter segmentAdapter = segment.asStorageAdapter(); analyzedColumns = analyzer.analyze(segmentAdapter, query.getAnalysisTypes()); numRows = segmentAdapter.getNumRows(); } else { analyzedColumns = analyzer.analyze(index, query.getAnalysisTypes()); numRows = index.getNumRows(); } if (query.hasSize()) { // Initialize with the size of the whitespace, 1 byte per totalSize = analyzedColumns.size() * numRows; } Map<String, ColumnAnalysis> columns = Maps.newTreeMap(); ColumnIncluderator includerator = query.getToInclude(); for (Map.Entry<String, ColumnAnalysis> entry : analyzedColumns.entrySet()) { final String columnName = entry.getKey(); final ColumnAnalysis column = entry.getValue(); if (!column.isError()) { totalSize += column.getSize(); } if (includerator.include(columnName)) { columns.put(columnName, column); } } return Sequences.simple(Arrays.asList(new SegmentAnalysis(segment.getIdentifier(), Arrays.asList(segment.getDataInterval()), columns, totalSize))); } }; } @Override public QueryRunner<SegmentAnalysis> mergeRunners(ExecutorService exec, Iterable<QueryRunner<SegmentAnalysis>> queryRunners) { final ListeningExecutorService queryExecutor = MoreExecutors.listeningDecorator(exec); return new ConcatQueryRunner<SegmentAnalysis>(Sequences.map(Sequences.simple(queryRunners), new Function<QueryRunner<SegmentAnalysis>, QueryRunner<SegmentAnalysis>>() { @Override public QueryRunner<SegmentAnalysis> apply(final QueryRunner<SegmentAnalysis> input) { return new QueryRunner<SegmentAnalysis>() { @Override public Sequence<SegmentAnalysis> run(final Query<SegmentAnalysis> query, final Map<String, Object> responseContext) { final int priority = query.getContextPriority(0); ListenableFuture<Sequence<SegmentAnalysis>> future = queryExecutor.submit( new AbstractPrioritizedCallable<Sequence<SegmentAnalysis>>(priority) { @Override public Sequence<SegmentAnalysis> call() throws Exception { return Sequences .simple(Sequences.toList(input.run(query, responseContext), new ArrayList<SegmentAnalysis>())); } }); try { queryWatcher.registerQuery(query, future); final Number timeout = query.getContextValue(QueryContextKeys.TIMEOUT, (Number) null); return timeout == null ? future.get() : future.get(timeout.longValue(), TimeUnit.MILLISECONDS); } catch (InterruptedException e) { log.warn(e, "Query interrupted, cancelling pending results, query id [%s]", query.getId()); future.cancel(true); throw new QueryInterruptedException("Query interrupted"); } catch (CancellationException e) { throw new QueryInterruptedException("Query cancelled"); } catch (TimeoutException e) { log.info("Query timeout, cancelling pending results for query id [%s]", query.getId()); future.cancel(true); throw new QueryInterruptedException("Query timeout"); } catch (ExecutionException e) { throw Throwables.propagate(e.getCause()); } } }; } })); } @Override public QueryToolChest<SegmentAnalysis, SegmentMetadataQuery> getToolchest() { return toolChest; } }