Java tutorial
/** * 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.crunch.io.hbase; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableSet; import com.google.common.collect.Lists; import com.google.common.primitives.Longs; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.crunch.DoFn; import org.apache.crunch.Emitter; import org.apache.crunch.FilterFn; import org.apache.crunch.GroupingOptions; import org.apache.crunch.MapFn; import org.apache.crunch.PCollection; import org.apache.crunch.PTable; import org.apache.crunch.Pair; import org.apache.crunch.Pipeline; import org.apache.crunch.impl.mr.MRPipeline; import org.apache.crunch.lib.sort.TotalOrderPartitioner; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.hbase.HColumnDescriptor; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.hbase.KeyValue; import org.apache.hadoop.hbase.client.HTable; import org.apache.hadoop.hbase.client.Put; import org.apache.hadoop.hbase.client.Result; import org.apache.hadoop.hbase.client.Scan; import org.apache.hadoop.hbase.io.TimeRange; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.io.RawComparator; import org.apache.hadoop.io.SequenceFile; import java.io.IOException; import java.io.Serializable; import java.nio.ByteBuffer; import java.util.Arrays; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.Map; import java.util.NavigableSet; import java.util.Set; import static org.apache.crunch.types.writable.Writables.bytes; import static org.apache.crunch.types.writable.Writables.nulls; import static org.apache.crunch.types.writable.Writables.tableOf; import static org.apache.crunch.types.writable.Writables.writables; public final class HFileUtils { private static final Log LOG = LogFactory.getLog(HFileUtils.class); /** Compares {@code KeyValue} by its family, qualifier, timestamp (reversely), type (reversely) and memstoreTS. */ private static final Comparator<KeyValue> KEY_VALUE_COMPARATOR = new Comparator<KeyValue>() { @Override public int compare(KeyValue l, KeyValue r) { int cmp; if ((cmp = compareFamily(l, r)) != 0) { return cmp; } if ((cmp = compareQualifier(l, r)) != 0) { return cmp; } if ((cmp = compareTimestamp(l, r)) != 0) { return cmp; } if ((cmp = compareType(l, r)) != 0) { return cmp; } return compareMemstoreTS(l, r); } private int compareFamily(KeyValue l, KeyValue r) { return Bytes.compareTo(l.getBuffer(), l.getFamilyOffset(), l.getFamilyLength(), r.getBuffer(), r.getFamilyOffset(), r.getFamilyLength()); } private int compareQualifier(KeyValue l, KeyValue r) { return Bytes.compareTo(l.getBuffer(), l.getQualifierOffset(), l.getQualifierLength(), r.getBuffer(), r.getQualifierOffset(), r.getQualifierLength()); } private int compareTimestamp(KeyValue l, KeyValue r) { return -Longs.compare(l.getTimestamp(), r.getTimestamp()); } private int compareType(KeyValue l, KeyValue r) { return (int) r.getType() - (int) l.getType(); } private int compareMemstoreTS(KeyValue l, KeyValue r) { return Longs.compare(l.getMemstoreTS(), r.getMemstoreTS()); } }; private static class FilterByFamilyFn extends FilterFn<KeyValue> { private final byte[] family; private FilterByFamilyFn(byte[] family) { this.family = family; } @Override public boolean accept(KeyValue input) { return Bytes.equals(input.getBuffer(), input.getFamilyOffset(), input.getFamilyLength(), family, 0, family.length); } } private static class StartRowFilterFn extends FilterFn<KeyValue> { private final byte[] startRow; private StartRowFilterFn(byte[] startRow) { this.startRow = startRow; } @Override public boolean accept(KeyValue input) { return Bytes.compareTo(input.getRow(), startRow) >= 0; } } private static class StopRowFilterFn extends FilterFn<KeyValue> { private final byte[] stopRow; private StopRowFilterFn(byte[] stopRow) { this.stopRow = stopRow; } @Override public boolean accept(KeyValue input) { return Bytes.compareTo(input.getRow(), stopRow) < 0; } } private static class FamilyMapFilterFn extends FilterFn<KeyValue> { private static class Column implements Serializable { private final byte[] family; private final byte[] qualifier; private Column(byte[] family, byte[] qualifier) { this.family = family; this.qualifier = qualifier; } private byte[] getFamily() { return family; } private byte[] getQualifier() { return qualifier; } } private final List<byte[]> families = Lists.newArrayList(); private final List<Column> qualifiers = Lists.newArrayList(); private transient Set<ByteBuffer> familySet; private transient Set<Pair<ByteBuffer, ByteBuffer>> qualifierSet; private FamilyMapFilterFn(Map<byte[], NavigableSet<byte[]>> familyMap) { // Holds good families and qualifiers in Lists, as ByteBuffer is not Serializable. for (Map.Entry<byte[], NavigableSet<byte[]>> e : familyMap.entrySet()) { byte[] f = e.getKey(); if (e.getValue() == null) { families.add(f); } else { for (byte[] q : e.getValue()) { qualifiers.add(new Column(f, q)); } } } } @Override public void initialize() { ImmutableSet.Builder<ByteBuffer> familiySetBuilder = ImmutableSet.builder(); ImmutableSet.Builder<Pair<ByteBuffer, ByteBuffer>> qualifierSetBuilder = ImmutableSet.builder(); for (byte[] f : families) { familiySetBuilder.add(ByteBuffer.wrap(f)); } for (Column e : qualifiers) { byte[] f = e.getFamily(); byte[] q = e.getQualifier(); qualifierSetBuilder.add(Pair.of(ByteBuffer.wrap(f), ByteBuffer.wrap(q))); } this.familySet = familiySetBuilder.build(); this.qualifierSet = qualifierSetBuilder.build(); } @Override public boolean accept(KeyValue input) { byte[] b = input.getBuffer(); ByteBuffer f = ByteBuffer.wrap(b, input.getFamilyOffset(), input.getFamilyLength()); ByteBuffer q = ByteBuffer.wrap(b, input.getQualifierOffset(), input.getQualifierLength()); return familySet.contains(f) || qualifierSet.contains(Pair.of(f, q)); } } private static class TimeRangeFilterFn extends FilterFn<KeyValue> { private final long minTimestamp; private final long maxTimestamp; private TimeRangeFilterFn(TimeRange timeRange) { // Can't save TimeRange to member directly, as it is not Serializable. this.minTimestamp = timeRange.getMin(); this.maxTimestamp = timeRange.getMax(); } @Override public boolean accept(KeyValue input) { return (minTimestamp <= input.getTimestamp() && input.getTimestamp() < maxTimestamp); } } private static class KeyValueComparator implements RawComparator<KeyValue> { @Override public int compare(byte[] left, int loffset, int llength, byte[] right, int roffset, int rlength) { // BytesWritable serialize length in first 4 bytes. // We simply ignore it here, because KeyValue has its own size serialized. if (llength < 4) { throw new AssertionError("Too small llength: " + llength); } if (rlength < 4) { throw new AssertionError("Too small rlength: " + rlength); } KeyValue leftKey = new KeyValue(left, loffset + 4, llength - 4); KeyValue rightKey = new KeyValue(right, roffset + 4, rlength - 4); return compare(leftKey, rightKey); } @Override public int compare(KeyValue left, KeyValue right) { return KeyValue.COMPARATOR.compare(left, right); } } private static final MapFn<KeyValue, ByteBuffer> EXTRACT_ROW_FN = new MapFn<KeyValue, ByteBuffer>() { @Override public ByteBuffer map(KeyValue input) { // we have to make a copy of row, because the buffer may be changed after this call return ByteBuffer.wrap(Arrays.copyOfRange(input.getBuffer(), input.getRowOffset(), input.getRowOffset() + input.getRowLength())); } }; public static PCollection<Result> scanHFiles(Pipeline pipeline, Path path) { return scanHFiles(pipeline, path, new Scan()); } /** * Scans HFiles with filter conditions. * * @param pipeline the pipeline * @param path path to HFiles * @param scan filtering conditions * @return {@code Result}s * @see #combineIntoRow(org.apache.crunch.PCollection, org.apache.hadoop.hbase.client.Scan) */ public static PCollection<Result> scanHFiles(Pipeline pipeline, Path path, Scan scan) { return scanHFiles(pipeline, ImmutableList.of(path), scan); } public static PCollection<Result> scanHFiles(Pipeline pipeline, List<Path> paths, Scan scan) { PCollection<KeyValue> in = pipeline.read(new HFileSource(paths, scan)); return combineIntoRow(in, scan); } public static PCollection<Result> combineIntoRow(PCollection<KeyValue> kvs) { return combineIntoRow(kvs, new Scan()); } /** * Converts a bunch of {@link KeyValue}s into {@link Result}. * * All {@code KeyValue}s belong to the same row are combined. Users may provide some filter * conditions (specified by {@code scan}). Deletes are dropped and only a specified number * of versions are kept. * * @param kvs the input {@code KeyValue}s * @param scan filter conditions, currently we support start row, stop row and family map * @return {@code Result}s */ public static PCollection<Result> combineIntoRow(PCollection<KeyValue> kvs, Scan scan) { if (!Bytes.equals(scan.getStartRow(), HConstants.EMPTY_START_ROW)) { kvs = kvs.filter(new StartRowFilterFn(scan.getStartRow())); } if (!Bytes.equals(scan.getStopRow(), HConstants.EMPTY_END_ROW)) { kvs = kvs.filter(new StopRowFilterFn(scan.getStopRow())); } if (scan.hasFamilies()) { kvs = kvs.filter(new FamilyMapFilterFn(scan.getFamilyMap())); } TimeRange timeRange = scan.getTimeRange(); if (timeRange != null && (timeRange.getMin() > 0 || timeRange.getMax() < Long.MAX_VALUE)) { kvs = kvs.filter(new TimeRangeFilterFn(timeRange)); } // TODO(chaoshi): support Scan#getFilter PTable<ByteBuffer, KeyValue> kvsByRow = kvs.by(EXTRACT_ROW_FN, bytes()); final int versions = scan.getMaxVersions(); return kvsByRow.groupByKey().parallelDo("CombineKeyValueIntoRow", new DoFn<Pair<ByteBuffer, Iterable<KeyValue>>, Result>() { @Override public void process(Pair<ByteBuffer, Iterable<KeyValue>> input, Emitter<Result> emitter) { List<KeyValue> kvs = Lists.newArrayList(); for (KeyValue kv : input.second()) { kvs.add(kv.clone()); // assuming the input fits into memory } Result result = doCombineIntoRow(kvs, versions); if (result == null) { return; } emitter.emit(result); } }, writables(Result.class)); } public static void writeToHFilesForIncrementalLoad(PCollection<KeyValue> kvs, HTable table, Path outputPath) throws IOException { HColumnDescriptor[] families = table.getTableDescriptor().getColumnFamilies(); if (families.length == 0) { LOG.warn(table + "has no column families"); return; } for (HColumnDescriptor f : families) { byte[] family = f.getName(); PCollection<KeyValue> sorted = sortAndPartition(kvs.filter(new FilterByFamilyFn(family)), table); sorted.write(new HFileTarget(new Path(outputPath, Bytes.toString(family)), f)); } } public static void writePutsToHFilesForIncrementalLoad(PCollection<Put> puts, HTable table, Path outputPath) throws IOException { PCollection<KeyValue> kvs = puts.parallelDo("ConvertPutToKeyValue", new DoFn<Put, KeyValue>() { @Override public void process(Put input, Emitter<KeyValue> emitter) { for (List<KeyValue> keyValues : input.getFamilyMap().values()) { for (KeyValue keyValue : keyValues) { emitter.emit(keyValue); } } } }, writables(KeyValue.class)); writeToHFilesForIncrementalLoad(kvs, table, outputPath); } public static PCollection<KeyValue> sortAndPartition(PCollection<KeyValue> kvs, HTable table) throws IOException { Configuration conf = kvs.getPipeline().getConfiguration(); PTable<KeyValue, Void> t = kvs.parallelDo(new MapFn<KeyValue, Pair<KeyValue, Void>>() { @Override public Pair<KeyValue, Void> map(KeyValue input) { return Pair.of(input, (Void) null); } }, tableOf(writables(KeyValue.class), nulls())); List<KeyValue> splitPoints = getSplitPoints(table); Path partitionFile = new Path(((MRPipeline) kvs.getPipeline()).createTempPath(), "partition"); writePartitionInfo(conf, partitionFile, splitPoints); GroupingOptions options = GroupingOptions.builder().partitionerClass(TotalOrderPartitioner.class) .conf(TotalOrderPartitioner.PARTITIONER_PATH, partitionFile.toString()) .numReducers(splitPoints.size() + 1).sortComparatorClass(KeyValueComparator.class).build(); return t.groupByKey(options).ungroup().keys(); } private static List<KeyValue> getSplitPoints(HTable table) throws IOException { List<byte[]> startKeys = ImmutableList.copyOf(table.getStartKeys()); if (startKeys.isEmpty()) { throw new AssertionError(table + " has no regions!"); } List<KeyValue> splitPoints = Lists.newArrayList(); for (byte[] startKey : startKeys.subList(1, startKeys.size())) { KeyValue kv = KeyValue.createFirstOnRow(startKey); LOG.debug("split row: " + Bytes.toString(kv.getRow())); splitPoints.add(kv); } return splitPoints; } private static void writePartitionInfo(Configuration conf, Path path, List<KeyValue> splitPoints) throws IOException { LOG.info("Writing " + splitPoints.size() + " split points to " + path); SequenceFile.Writer writer = SequenceFile.createWriter(path.getFileSystem(conf), conf, path, NullWritable.class, KeyValue.class); for (KeyValue key : splitPoints) { writer.append(NullWritable.get(), writables(KeyValue.class).getOutputMapFn().map(key)); } writer.close(); } private static Result doCombineIntoRow(List<KeyValue> kvs, int versions) { // shortcut for the common case if (kvs.isEmpty()) { return null; } if (kvs.size() == 1 && kvs.get(0).getType() == KeyValue.Type.Put.getCode()) { return new Result(kvs); } kvs = maybeDeleteFamily(kvs); // In-place sort KeyValues by family, qualifier and then timestamp reversely (whenever ties, deletes appear first). Collections.sort(kvs, KEY_VALUE_COMPARATOR); List<KeyValue> results = Lists.newArrayListWithCapacity(kvs.size()); for (int i = 0, j; i < kvs.size(); i = j) { j = i + 1; while (j < kvs.size() && hasSameFamilyAndQualifier(kvs.get(i), kvs.get(j))) { j++; } results.addAll(getLatestKeyValuesOfColumn(kvs.subList(i, j), versions)); } if (results.isEmpty()) { return null; } return new Result(results); } /** * In-place removes any {@link KeyValue}s whose timestamp is less than or equal to the * delete family timestamp. Also removes the delete family {@code KeyValue}s. */ private static List<KeyValue> maybeDeleteFamily(List<KeyValue> kvs) { long deleteFamilyCut = -1; for (KeyValue kv : kvs) { if (kv.getType() == KeyValue.Type.DeleteFamily.getCode()) { deleteFamilyCut = Math.max(deleteFamilyCut, kv.getTimestamp()); } } if (deleteFamilyCut == 0) { return kvs; } List<KeyValue> results = Lists.newArrayList(); for (KeyValue kv : kvs) { if (kv.getType() == KeyValue.Type.DeleteFamily.getCode()) { continue; } if (kv.getTimestamp() <= deleteFamilyCut) { continue; } results.add(kv); } return results; } private static boolean hasSameFamilyAndQualifier(KeyValue l, KeyValue r) { return Bytes.equals(l.getBuffer(), l.getFamilyOffset(), l.getFamilyLength(), r.getBuffer(), r.getFamilyOffset(), r.getFamilyLength()) && Bytes.equals(l.getBuffer(), l.getQualifierOffset(), l.getQualifierLength(), r.getBuffer(), r.getQualifierOffset(), r.getQualifierLength()); } /** * Goes over the given {@link KeyValue}s and remove {@code Delete}s and {@code DeleteColumn}s. * * @param kvs {@code KeyValue}s that of same row and column and sorted by timestamps in * descending order * @param versions the number of versions to keep * @return the resulting {@code KeyValue}s that contains only {@code Put}s */ private static List<KeyValue> getLatestKeyValuesOfColumn(List<KeyValue> kvs, int versions) { if (kvs.isEmpty()) { return kvs; } if (kvs.get(0).getType() == KeyValue.Type.Put.getCode()) { return kvs; // shortcut for the common case } List<KeyValue> results = Lists.newArrayListWithCapacity(versions); long previousDeleteTimestamp = -1; for (KeyValue kv : kvs) { if (results.size() >= versions) { break; } if (kv.getType() == KeyValue.Type.DeleteColumn.getCode()) { break; } else if (kv.getType() == KeyValue.Type.Put.getCode()) { if (kv.getTimestamp() != previousDeleteTimestamp) { results.add(kv); } } else if (kv.getType() == KeyValue.Type.Delete.getCode()) { previousDeleteTimestamp = kv.getTimestamp(); } else { throw new AssertionError("Unexpected KeyValue type: " + kv.getType()); } } return results; } }