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From: keith-turner <git@git.apache.org>
To: dev@accumulo.apache.org
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References: <git-pr-103-accumulo@git.apache.org>
In-Reply-To: <git-pr-103-accumulo@git.apache.org>
Subject: [GitHub] accumulo pull request: ACCUMULO-4165 Added a user facing API for RFile
Content-Type: text/plain
Message-Id: <20160531173944.C04CDDFB74@git1-us-west.apache.org>
Date: Tue, 31 May 2016 17:39:44 +0000 (UTC)
archived-at: Tue, 31 May 2016 17:39:47 -0000

Github user keith-turner commented on a diff in the pull request:

    https://github.com/apache/accumulo/pull/103#discussion_r65228669
  
    --- Diff: core/src/main/java/org/apache/accumulo/core/client/rfile/RFileScanner.java ---
    @@ -0,0 +1,330 @@
    +/*
    + * 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.client.rfile;
    +
    +import java.io.IOException;
    +import java.util.ArrayList;
    +import java.util.Collections;
    +import java.util.HashMap;
    +import java.util.Iterator;
    +import java.util.List;
    +import java.util.Map.Entry;
    +import java.util.Set;
    +import java.util.SortedSet;
    +import java.util.concurrent.TimeUnit;
    +
    +import org.apache.accumulo.core.client.IteratorSetting;
    +import org.apache.accumulo.core.client.Scanner;
    +import org.apache.accumulo.core.client.impl.BaseIteratorEnvironment;
    +import org.apache.accumulo.core.client.impl.ScannerOptions;
    +import org.apache.accumulo.core.client.rfile.RFileScannerBuilder.InputArgs;
    +import org.apache.accumulo.core.client.sample.SamplerConfiguration;
    +import org.apache.accumulo.core.conf.AccumuloConfiguration;
    +import org.apache.accumulo.core.conf.ConfigurationCopy;
    +import org.apache.accumulo.core.conf.Property;
    +import org.apache.accumulo.core.data.ByteSequence;
    +import org.apache.accumulo.core.data.Column;
    +import org.apache.accumulo.core.data.Key;
    +import org.apache.accumulo.core.data.Range;
    +import org.apache.accumulo.core.data.Value;
    +import org.apache.accumulo.core.file.blockfile.cache.BlockCache;
    +import org.apache.accumulo.core.file.blockfile.cache.CacheEntry;
    +import org.apache.accumulo.core.file.blockfile.cache.LruBlockCache;
    +import org.apache.accumulo.core.file.blockfile.impl.CachableBlockFile;
    +import org.apache.accumulo.core.file.rfile.RFile;
    +import org.apache.accumulo.core.file.rfile.RFile.Reader;
    +import org.apache.accumulo.core.iterators.IteratorAdapter;
    +import org.apache.accumulo.core.iterators.IteratorUtil;
    +import org.apache.accumulo.core.iterators.IteratorUtil.IteratorScope;
    +import org.apache.accumulo.core.iterators.SortedKeyValueIterator;
    +import org.apache.accumulo.core.iterators.system.MultiIterator;
    +import org.apache.accumulo.core.sample.impl.SamplerConfigurationImpl;
    +import org.apache.accumulo.core.security.Authorizations;
    +import org.apache.accumulo.core.util.LocalityGroupUtil;
    +import org.apache.hadoop.fs.FSDataInputStream;
    +import org.apache.hadoop.io.Text;
    +
    +import com.google.common.base.Preconditions;
    +
    +class RFileScanner extends ScannerOptions implements Scanner {
    +
    +  private Range range;
    +  private BlockCache dataCache = null;
    +  private BlockCache indexCache = null;
    +  private Opts opts;
    +  private int batchSize = 1000;
    +  private long readaheadThreshold = 3;
    +
    +  private static final long CACHE_BLOCK_SIZE = AccumuloConfiguration.getDefaultConfiguration().getMemoryInBytes(Property.TSERV_DEFAULT_BLOCKSIZE);
    +
    +  static class Opts {
    +    InputArgs in;
    +    Authorizations auths = Authorizations.EMPTY;
    +    long dataCacheSize;
    +    long indexCacheSize;
    +    boolean useSystemIterators = true;
    +    Text lowerBound;
    +    Text upperBound;
    +    public HashMap<String,String> tableConfig;
    +  }
    +
    +  // This cache exist as a hack to avoid leaking decompressors. When the RFile code is not given a
    +  // cache it reads blocks directly from the decompressor. However if a user does not read all data
    +  // for a scan this can leave a BCFile block open and a decompressor allocated.
    +  //
    +  // By providing a cache to the RFile code it forces each block to be read into memory. When a
    +  // block is accessed the entire thing is read into memory immediately allocating and deallocating
    +  // a decompressor. If the user does not read all data, no decompressors are left allocated.
    +  private static class NoopCache implements BlockCache {
    +    @Override
    +    public CacheEntry cacheBlock(String blockName, byte[] buf, boolean inMemory) {
    +      return null;
    +    }
    +
    +    @Override
    +    public CacheEntry cacheBlock(String blockName, byte[] buf) {
    +      return null;
    +    }
    +
    +    @Override
    +    public CacheEntry getBlock(String blockName) {
    +      return null;
    +    }
    +
    +    @Override
    +    public long getMaxSize() {
    +      return Integer.MAX_VALUE;
    +    }
    +  }
    +
    +  RFileScanner(Opts opts) {
    +    if (!opts.auths.equals(Authorizations.EMPTY) && !opts.useSystemIterators) {
    +      throw new IllegalArgumentException("Set authorizations and specified not to use system iterators");
    +    }
    +
    +    this.opts = opts;
    +    if (opts.indexCacheSize > 0) {
    +      this.indexCache = new LruBlockCache(opts.indexCacheSize, CACHE_BLOCK_SIZE);
    +    } else {
    +      this.indexCache = new NoopCache();
    +    }
    +
    +    if (opts.dataCacheSize > 0) {
    +      this.dataCache = new LruBlockCache(opts.dataCacheSize, CACHE_BLOCK_SIZE);
    +    } else {
    +      this.dataCache = new NoopCache();
    +    }
    +  }
    +
    +  @Override
    +  public synchronized void fetchColumnFamily(Text col) {
    +    Preconditions.checkArgument(opts.useSystemIterators, "Can only fetch columns when using system iterators");
    +    super.fetchColumnFamily(col);
    +  }
    +
    +  @Override
    +  public synchronized void fetchColumn(Text colFam, Text colQual) {
    +    Preconditions.checkArgument(opts.useSystemIterators, "Can only fetch columns when using system iterators");
    +    super.fetchColumn(colFam, colQual);
    +  }
    +
    +  @Override
    +  public void fetchColumn(IteratorSetting.Column column) {
    +    Preconditions.checkArgument(opts.useSystemIterators, "Can only fetch columns when using system iterators");
    +    super.fetchColumn(column);
    +  }
    +
    +  @Override
    +  public void setClassLoaderContext(String classLoaderContext) {
    +    throw new UnsupportedOperationException();
    +  }
    +
    +  @Deprecated
    +  @Override
    +  public void setTimeOut(int timeOut) {
    +    if (timeOut == Integer.MAX_VALUE)
    +      setTimeout(Long.MAX_VALUE, TimeUnit.MILLISECONDS);
    +    else
    +      setTimeout(timeOut, TimeUnit.SECONDS);
    +  }
    +
    +  @Deprecated
    +  @Override
    +  public int getTimeOut() {
    +    long timeout = getTimeout(TimeUnit.SECONDS);
    +    if (timeout >= Integer.MAX_VALUE)
    +      return Integer.MAX_VALUE;
    +    return (int) timeout;
    +  }
    +
    +  @Override
    +  public void setRange(Range range) {
    +    this.range = range;
    +  }
    +
    +  @Override
    +  public Range getRange() {
    +    return range;
    +  }
    +
    +  @Override
    +  public void setBatchSize(int size) {
    +    this.batchSize = size;
    +  }
    +
    +  @Override
    +  public int getBatchSize() {
    +    return batchSize;
    +  }
    +
    +  @Override
    +  public void enableIsolation() {}
    +
    +  @Override
    +  public void disableIsolation() {}
    +
    +  @Override
    +  public synchronized void setReadaheadThreshold(long batches) {
    +    Preconditions.checkArgument(batches > 0);
    +    readaheadThreshold = batches;
    +  }
    +
    +  @Override
    +  public synchronized long getReadaheadThreshold() {
    +    return readaheadThreshold;
    +  }
    +
    +  @Override
    +  public Authorizations getAuthorizations() {
    +    return opts.auths;
    +  }
    +
    +  @Override
    +  public void addScanIterator(IteratorSetting cfg) {
    +    super.addScanIterator(cfg);
    +  }
    +
    +  @Override
    +  public void removeScanIterator(String iteratorName) {
    +    super.removeScanIterator(iteratorName);
    +  }
    +
    +  @Override
    +  public void updateScanIteratorOption(String iteratorName, String key, String value) {
    +    super.updateScanIteratorOption(iteratorName, key, value);
    +  }
    +
    +  private static final Range EMPTY_RANGE = new Range();
    +
    +  private class IterEnv extends BaseIteratorEnvironment {
    +    @Override
    +    public IteratorScope getIteratorScope() {
    +      return IteratorScope.scan;
    +    }
    +
    +    @Override
    +    public boolean isFullMajorCompaction() {
    +      return false;
    +    }
    +
    +    @Override
    +    public Authorizations getAuthorizations() {
    +      return opts.auths;
    +    }
    +
    +    @Override
    +    public boolean isSamplingEnabled() {
    +      return RFileScanner.this.getSamplerConfiguration() != null;
    +    }
    +
    +    @Override
    +    public SamplerConfiguration getSamplerConfiguration() {
    +      return RFileScanner.this.getSamplerConfiguration();
    +    }
    +  }
    +
    +  @Override
    +  public Iterator<Entry<Key,Value>> iterator() {
    +    try {
    +      RFileSource[] sources = opts.in.getSources();
    +      List<SortedKeyValueIterator<Key,Value>> readers = new ArrayList<>(sources.length);
    +      for (int i = 0; i < sources.length; i++) {
    +        FSDataInputStream inputStream = (FSDataInputStream) sources[i].getInputStream();
    +        readers.add(new RFile.Reader(new CachableBlockFile.Reader(inputStream, sources[i].getLength(), opts.in.getConf(), dataCache, indexCache,
    +            AccumuloConfiguration.getDefaultConfiguration())));
    +      }
    +
    +      if (getSamplerConfiguration() != null) {
    +        for (int i = 0; i < readers.size(); i++) {
    +          readers.set(i, ((Reader) readers.get(i)).getSample(new SamplerConfigurationImpl(getSamplerConfiguration())));
    +        }
    +      }
    +
    +      SortedKeyValueIterator<Key,Value> iterator;
    +      if (opts.lowerBound != null || opts.upperBound != null) {
    +        iterator = new MultiIterator(readers, new Range(opts.lowerBound, false, opts.upperBound, true));
    --- End diff --
    
    > At a glance, it looked like the lowerBound and upperBound attributes on the opts variable were losing "precision" over what is usually possible via an end-user's use of Range directly. 
    
    Ok.   When I wrote the API methods I thought that MultiIterator only supported row ranges.  Then I got there and found otherwise, but left it as is.  Based on your comment I am thinking maybe there should just be a `setBounds(Range range)` method.  


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