Github user joshelser commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/224#discussion_r105251834
--- Diff: core/src/main/java/org/apache/accumulo/core/summary/Gatherer.java
---
@@ -0,0 +1,513 @@
+/*
+ * 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.accumulo.core.summary;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+import org.apache.accumulo.core.client.AccumuloException;
+import org.apache.accumulo.core.client.AccumuloSecurityException;
+import org.apache.accumulo.core.client.TableNotFoundException;
+import org.apache.accumulo.core.client.impl.ClientContext;
+import org.apache.accumulo.core.client.impl.ServerClient;
+import org.apache.accumulo.core.client.impl.thrift.TRowRange;
+import org.apache.accumulo.core.client.impl.thrift.TSummaries;
+import org.apache.accumulo.core.client.impl.thrift.TSummaryRequest;
+import org.apache.accumulo.core.client.summary.SummarizerConfiguration;
+import org.apache.accumulo.core.conf.AccumuloConfiguration;
+import org.apache.accumulo.core.data.ByteSequence;
+import org.apache.accumulo.core.data.Key;
+import org.apache.accumulo.core.data.Range;
+import org.apache.accumulo.core.data.impl.KeyExtent;
+import org.apache.accumulo.core.file.blockfile.cache.BlockCache;
+import org.apache.accumulo.core.metadata.schema.MetadataScanner;
+import org.apache.accumulo.core.metadata.schema.TabletMetadata;
+import org.apache.accumulo.core.rpc.ThriftUtil;
+import
org.apache.accumulo.core.tabletserver.thrift.TabletClientService.Client;
+import org.apache.accumulo.core.trace.Tracer;
+import org.apache.accumulo.core.trace.thrift.TInfo;
+import org.apache.accumulo.core.util.ByteBufferUtil;
+import org.apache.accumulo.core.util.CachedConfiguration;
+import org.apache.accumulo.core.util.TextUtil;
+import org.apache.accumulo.fate.util.UtilWaitThread;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.Text;
+import org.apache.thrift.TApplicationException;
+import org.apache.thrift.transport.TTransportException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+import com.google.common.hash.Hashing;
+import com.google.common.net.HostAndPort;
+
+/**
+ * This class implements using multiple tservers to gather summaries.
+ *
+ * Below is a rough outline of the RPC process.
+ *
+ * <ol>
+ * <li>Clients pick a random tserver and make an RPC to remotely execute
{@link #gather()}.
+ * <li> {@link #gather()} will call make RPC calls to multiple tservers to
remotely execute {@link #processPartition(int, int)}
+ * <li> {@link #processPartition(int, int)} will make RPC calls to
multiple tserver to remotely execute
+ * {@link #processFiles(FileSystemResolver, Map, BlockCache, BlockCache,
ExecutorService)}
+ * </ol>
+ */
+public class Gatherer {
+
+ private static final Logger log =
LoggerFactory.getLogger(Gatherer.class);
+
+ private ClientContext ctx;
+ private String tableId;
+ private SummarizerFactory factory;
+ private Text startRow = null;
+ private Text endRow = null;
+ private Range clipRange;
+ private Predicate<SummarizerConfiguration> summarySelector;
+
+ private TSummaryRequest request;
+
+ private String summarizerPattern;
+
+ private Set<SummarizerConfiguration> summaries;
+
+ public Gatherer(ClientContext context, TSummaryRequest request,
AccumuloConfiguration tableConfig) {
+ this.ctx = context;
+ this.tableId = request.tableId;
+ this.startRow = ByteBufferUtil.toText(request.bounds.startRow);
+ this.endRow = ByteBufferUtil.toText(request.bounds.endRow);
+ this.clipRange = new Range(startRow, false, endRow, true);
+ this.summaries =
request.getSummarizers().stream().map(SummarizerConfigurationUtil::fromThrift).collect(Collectors.toSet());
+ this.request = request;
+
+ this.summarizerPattern = request.getSummarizerPattern();
+
+ if (summarizerPattern != null) {
+ Pattern pattern = Pattern.compile(summarizerPattern);
+ // The way conf is converted to string below is documented in the
API, so consider this when making changes!
+ summarySelector = conf -> pattern.matcher(conf.getClassName() + " "
+ new TreeMap<>(conf.getOptions())).matches();
+ if (!summaries.isEmpty()) {
+ summarySelector = summarySelector.or(conf ->
summaries.contains(conf));
+ }
+ } else if (!summaries.isEmpty()) {
+ summarySelector = conf -> summaries.contains(conf);
+ } else {
+ summarySelector = conf -> true;
+ }
+
+ this.factory = new SummarizerFactory(tableConfig);
+ }
+
+ private TSummaryRequest getRequest() {
+ return request;
+ }
+
+ /**
+ * @param fileSelector
+ * only returns files that match this predicate
+ * @return A map of the form : {@code map<tserver location, map<path,
list<range>>} . The ranges associated with a file represent the tablets that
use the
+ * file.
+ */
+ private Map<String,Map<String,List<TRowRange>>>
getFilesGroupedByLocation(Predicate<String> fileSelector) throws
TableNotFoundException, AccumuloException,
+ AccumuloSecurityException {
+
+ Iterable<TabletMetadata> tmi =
MetadataScanner.builder().from(ctx).overUserTableId(tableId, startRow,
endRow).fetchFiles().fetchLocation().fetchLast()
+ .fetchPrev().build();
+
+ // get a subset of files
+ Map<String,List<TabletMetadata>> files = new HashMap<>();
+ for (TabletMetadata tm : tmi) {
+ for (String file : tm.getFiles()) {
+ if (fileSelector.test(file)) {
+ // TODO push this filtering to server side and possibly use
batch scanner
+ files.computeIfAbsent(file, s -> new ArrayList<>()).add(tm);
+ }
+ }
+ }
+
+ // group by location, then file
+
+ Map<String,Map<String,List<TRowRange>>> locations = new HashMap<>();
+
+ List<String> tservers = null;
+
+ for (Entry<String,List<TabletMetadata>> entry : files.entrySet()) {
+
+ String location = entry.getValue().stream().filter(tm ->
tm.getLocation() != null) // filter tablets w/o a location
+ .map(tm -> tm.getLocation().getHostAndPort().toString()) //
convert to host:port strings
+ .min(String::compareTo) // find minimum host:port
+ .orElse(entry.getValue().stream().filter(tm -> tm.getLast() !=
null) // if no locations, then look at last locations
+ .map(tm -> tm.getLast().getHostAndPort().toString()) //
convert to host:port strings
+ .min(String::compareTo).orElse(null)); // find minimum last
location or return null
+
+ if (location == null) {
+ if (tservers == null) {
+ tservers =
ctx.getConnector().instanceOperations().getTabletServers();
+ Collections.sort(tservers);
+ }
+
+ // When no location, the approach below will consistently choose
the same tserver for the same file (as long as the set of tservers is stable).
+ int idx =
Math.abs(Hashing.murmur3_32().hashString(entry.getKey()).asInt()) %
tservers.size();
+ location = tservers.get(idx);
+ }
+
+ List<Range> merged =
Range.mergeOverlapping(Lists.transform(entry.getValue(), tm ->
tm.getExtent().toDataRange())); // merge contiguous ranges
+ List<TRowRange> ranges = merged.stream().map(r ->
toClippedExtent(r).toThrift()).collect(Collectors.toList()); // clip ranges to
queried range
+
+ locations.computeIfAbsent(location, s -> new
HashMap<>()).put(entry.getKey(), ranges);
+ }
+
+ return locations;
+ }
+
+ private <K,V> Iterable<Map<K,V>> partition(Map<K,V> map, int max) {
+
+ if (map.size() < max) {
+ return Collections.singletonList(map);
+ }
+
+ return new Iterable<Map<K,V>>() {
+ @Override
+ public Iterator<Map<K,V>> iterator() {
+ Iterator<Entry<K,V>> esi = map.entrySet().iterator();
+
+ return new Iterator<Map<K,V>>() {
+ @Override
+ public boolean hasNext() {
+ return esi.hasNext();
+ }
+
+ @Override
+ public Map<K,V> next() {
+ Map<K,V> workingMap = new HashMap<>(max);
+ while (esi.hasNext() && workingMap.size() < max) {
+ Entry<K,V> entry = esi.next();
+ workingMap.put(entry.getKey(), entry.getValue());
+ }
+ return workingMap;
+ }
+ };
+ }
+ };
+ }
+
+ private static class ProcessedFiles {
+ final SummaryCollection summaries;
+ final Set<String> failedFiles;
+
+ public ProcessedFiles() {
+ this.summaries = new SummaryCollection();
+ this.failedFiles = new HashSet<>();
+ }
+ }
+
+ private class FilesProcessor implements Callable<ProcessedFiles> {
+
+ HostAndPort location;
+ Map<String,List<TRowRange>> allFiles;
+ private TInfo tinfo;
+
+ public FilesProcessor(TInfo tinfo, HostAndPort location,
Map<String,List<TRowRange>> allFiles) {
+ this.location = location;
+ this.allFiles = allFiles;
+ this.tinfo = tinfo;
+ }
+
+ @Override
+ public ProcessedFiles call() throws Exception {
+ ProcessedFiles pfiles = new ProcessedFiles();
+
+ Client client = null;
+ try {
+ client = ThriftUtil.getTServerClient(location, ctx);
+ // partition files into smaller chunks so that not too many are
sent to a tserver at once
+ for (Map<String,List<TRowRange>> files : partition(allFiles, 500))
{
+ if (pfiles.failedFiles.size() > 0) {
+ // there was a previous failure on this tserver, so just fail
the rest of the files
+ pfiles.failedFiles.addAll(files.keySet());
+ continue;
+ }
+
+ TSummaries tSums = null;
+ try {
+ tSums = client.getSummariesFromFiles(tinfo, ctx.rpcCreds(),
getRequest(), files);
+ } catch (TApplicationException tae) {
+ throw tae;
+ } catch (TTransportException e) {
+ pfiles.failedFiles.addAll(files.keySet());
+ continue;
+ }
+
+ pfiles.summaries.merge(new SummaryCollection(tSums), factory);
+ }
+ } finally {
+ ThriftUtil.returnClient(client);
+ }
+
+ return pfiles;
+ }
+ }
+
+ /**
+ * This methods reads a subset of file paths into memory and groups them
by location. Then it request sumaries for files from each location/tablet
server.
+ */
+ public SummaryCollection processPartition(int modulus, int remainder)
throws TableNotFoundException, AccumuloException, AccumuloSecurityException {
+
+ Predicate<String> hashingFileSelector = file ->
Math.abs(Hashing.murmur3_32().hashString(file).asInt()) % modulus == remainder;
+
+ Map<String,Map<String,List<TRowRange>>> filesGBL =
getFilesGroupedByLocation(hashingFileSelector);
+
+ SummaryCollection partitionSummaries = new SummaryCollection();
+
+ ExecutorService execSrv = Executors.newCachedThreadPool();
+ try {
+ TInfo tinfo = Tracer.traceInfo();
+ while (true) {
+ Set<String> failedFiles = new HashSet<>();
+
+ List<Future<ProcessedFiles>> futures = new ArrayList<>();
+ for (Entry<String,Map<String,List<TRowRange>>> entry :
filesGBL.entrySet()) {
+ HostAndPort location = HostAndPort.fromString(entry.getKey());
+ Map<String,List<TRowRange>> allFiles = entry.getValue();
+
+ Future<ProcessedFiles> future = execSrv.submit(new
FilesProcessor(tinfo, location, allFiles));
+ futures.add(future);
+ }
+
+ for (Future<ProcessedFiles> future : futures) {
+ try {
+ ProcessedFiles pfiles = future.get();
+ if (pfiles.summaries.getTotalFiles() > 0) {
+ partitionSummaries.merge(pfiles.summaries, factory);
+ }
+
+ failedFiles.addAll(pfiles.failedFiles);
+ } catch (InterruptedException | ExecutionException e) {
+ throw new AccumuloException(e);
+ }
+ }
+
+ if (failedFiles.size() > 0) {
+ // get new locations just for failed files
+ Predicate<String> fileSelector = hashingFileSelector.and(file ->
failedFiles.contains(file));
+ filesGBL = getFilesGroupedByLocation(fileSelector);
+ UtilWaitThread.sleep(250);
+ } else {
+ break;
+ }
+ }
+ } finally {
+ execSrv.shutdownNow();
+ }
+
+ return partitionSummaries;
+ }
+
+ public static interface FileSystemResolver {
+ FileSystem get(Path file);
+ }
+
+ /**
+ * This method will read summaries from a set of files.
+ */
+ public SummaryCollection processFiles(FileSystemResolver volMgr,
Map<String,List<TRowRange>> files, BlockCache summaryCache, BlockCache
indexCache,
+ ExecutorService srp) {
+ SummaryCollection fileSummaries = new SummaryCollection();
+
+ List<Future<SummaryCollection>> futures = new ArrayList<>();
+ for (Entry<String,List<TRowRange>> entry : files.entrySet()) {
+ Future<SummaryCollection> future = srp.submit(() -> {
+ List<RowRange> rrl = Lists.transform(entry.getValue(),
RowRange::new);
+ return getSummaries(volMgr, entry.getKey(), rrl, summaryCache,
indexCache);
+ });
+ futures.add(future);
+ }
+
+ for (Future<SummaryCollection> future : futures) {
+ try {
+ fileSummaries.merge(future.get(), factory);
+ } catch (ExecutionException | InterruptedException e) {
+ throw new RuntimeException(e);
--- End diff --
Should be a good citizen and re-set the interrupted state when catching
`InterruptedExeption`.
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