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MAPREDUCE-5402. In DynamicInputFormat, change MAX_CHUNKS_TOLERABLE, MAX_CHUNKS_IDEAL, MIN_RECORDS_PER_CHUNK and SPLIT_RATIO to be configurable. Contributed by Tsuyoshi OZAWA

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git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1592703 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Tsz-wo Sze 2014-05-06 10:24:10 +00:00
parent 17d4fbbf0a
commit 03db13206f
4 changed files with 125 additions and 18 deletions
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4
hadoop-mapreduce-project/CHANGES.txt
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@ -178,6 +178,10 @@ Release 2.5.0 - UNRELEASED
MAPREDUCE-5638. Port Hadoop Archives document to trunk (Akira AJISAKA via
jeagles)
MAPREDUCE-5402. In DynamicInputFormat, change MAX_CHUNKS_TOLERABLE,
MAX_CHUNKS_IDEAL, MIN_RECORDS_PER_CHUNK and SPLIT_RATIO to be configurable.
(Tsuyoshi OZAWA via szetszwo)
OPTIMIZATIONS
BUG FIXES

20
hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCpConstants.java
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@ -51,7 +51,16 @@ public class DistCpConstants {
public static final String CONF_LABEL_SKIP_CRC = "distcp.skip.crc";
public static final String CONF_LABEL_OVERWRITE = "distcp.copy.overwrite";
public static final String CONF_LABEL_BANDWIDTH_MB = "distcp.map.bandwidth.mb";
public static final String CONF_LABEL_MAX_CHUNKS_TOLERABLE =
"distcp.dynamic.max.chunks.tolerable";
public static final String CONF_LABEL_MAX_CHUNKS_IDEAL =
"distcp.dynamic.max.chunks.ideal";
public static final String CONF_LABEL_MIN_RECORDS_PER_CHUNK =
"distcp.dynamic.min.records_per_chunk";
public static final String CONF_LABEL_SPLIT_RATIO =
"distcp.dynamic.split.ratio";
/* Total bytes to be copied. Updated by copylisting. Unfiltered count */
public static final String CONF_LABEL_TOTAL_BYTES_TO_BE_COPIED = "mapred.total.bytes.expected";
@ -107,4 +116,13 @@ public class DistCpConstants {
public static final int INVALID_ARGUMENT = -1;
public static final int DUPLICATE_INPUT = -2;
public static final int UNKNOWN_ERROR = -999;
/**
* Constants for DistCp default values of configurable values
*/
public static final int MAX_CHUNKS_TOLERABLE_DEFAULT = 400;
public static final int MAX_CHUNKS_IDEAL_DEFAULT = 100;
public static final int MIN_RECORDS_PER_CHUNK_DEFAULT = 5;
public static final int SPLIT_RATIO_DEFAULT = 2;
}

98
hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/mapred/lib/DynamicInputFormat.java
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@ -57,7 +57,7 @@ public class DynamicInputFormat<K, V> extends InputFormat<K, V> {
= "mapred.num.splits";
private static final String CONF_LABEL_NUM_ENTRIES_PER_CHUNK
= "mapred.num.entries.per.chunk";
/**
* Implementation of InputFormat::getSplits(). This method splits up the
* copy-listing file into chunks, and assigns the first batch to different
@ -91,7 +91,7 @@ private List<InputSplit> createSplits(JobContext jobContext,
// Setting non-zero length for FileSplit size, to avoid a possible
// future when 0-sized file-splits are considered "empty" and skipped
// over.
MIN_RECORDS_PER_CHUNK,
getMinRecordsPerChunk(jobContext.getConfiguration()),
null));
}
DistCpUtils.publish(jobContext.getConfiguration(),
@ -107,9 +107,11 @@ private List<InputSplit> createSplits(JobContext jobContext,
final Configuration configuration = context.getConfiguration();
int numRecords = getNumberOfRecords(configuration);
int numMaps = getNumMapTasks(configuration);
int maxChunksTolerable = getMaxChunksTolerable(configuration);
// Number of chunks each map will process, on average.
int splitRatio = getListingSplitRatio(configuration, numMaps, numRecords);
validateNumChunksUsing(splitRatio, numMaps);
validateNumChunksUsing(splitRatio, numMaps, maxChunksTolerable);
int numEntriesPerChunk = (int)Math.ceil((float)numRecords
/(splitRatio * numMaps));
@ -168,9 +170,9 @@ private List<InputSplit> createSplits(JobContext jobContext,
return chunksFinal;
}
private static void validateNumChunksUsing(int splitRatio, int numMaps)
throws IOException {
if (splitRatio * numMaps > MAX_CHUNKS_TOLERABLE)
private static void validateNumChunksUsing(int splitRatio, int numMaps,
int maxChunksTolerable) throws IOException {
if (splitRatio * numMaps > maxChunksTolerable)
throw new IOException("Too many chunks created with splitRatio:"
+ splitRatio + ", numMaps:" + numMaps
+ ". Reduce numMaps or decrease split-ratio to proceed.");
@ -238,14 +240,61 @@ private static int getListingSplitRatio(Configuration configuration,
int numMaps, int numPaths) {
return configuration.getInt(
CONF_LABEL_LISTING_SPLIT_RATIO,
getSplitRatio(numMaps, numPaths));
getSplitRatio(numMaps, numPaths, configuration));
}
private static int getMaxChunksTolerable(Configuration conf) {
int maxChunksTolerable = conf.getInt(
DistCpConstants.CONF_LABEL_MAX_CHUNKS_TOLERABLE,
DistCpConstants.MAX_CHUNKS_TOLERABLE_DEFAULT);
if (maxChunksTolerable <= 0) {
LOG.warn(DistCpConstants.CONF_LABEL_MAX_CHUNKS_TOLERABLE +
" should be positive. Fall back to default value: "
+ DistCpConstants.MAX_CHUNKS_TOLERABLE_DEFAULT);
maxChunksTolerable = DistCpConstants.MAX_CHUNKS_TOLERABLE_DEFAULT;
}
return maxChunksTolerable;
}
private static int getMaxChunksIdeal(Configuration conf) {
int maxChunksIdeal = conf.getInt(
DistCpConstants.CONF_LABEL_MAX_CHUNKS_IDEAL,
DistCpConstants.MAX_CHUNKS_IDEAL_DEFAULT);
if (maxChunksIdeal <= 0) {
LOG.warn(DistCpConstants.CONF_LABEL_MAX_CHUNKS_IDEAL +
" should be positive. Fall back to default value: "
+ DistCpConstants.MAX_CHUNKS_IDEAL_DEFAULT);
maxChunksIdeal = DistCpConstants.MAX_CHUNKS_IDEAL_DEFAULT;
}
return maxChunksIdeal;
}
private static int getMinRecordsPerChunk(Configuration conf) {
int minRecordsPerChunk = conf.getInt(
DistCpConstants.CONF_LABEL_MIN_RECORDS_PER_CHUNK,
DistCpConstants.MIN_RECORDS_PER_CHUNK_DEFAULT);
if (minRecordsPerChunk <= 0) {
LOG.warn(DistCpConstants.CONF_LABEL_MIN_RECORDS_PER_CHUNK +
" should be positive. Fall back to default value: "
+ DistCpConstants.MIN_RECORDS_PER_CHUNK_DEFAULT);
minRecordsPerChunk = DistCpConstants.MIN_RECORDS_PER_CHUNK_DEFAULT;
}
return minRecordsPerChunk;
}
private static final int MAX_CHUNKS_TOLERABLE = 400;
private static final int MAX_CHUNKS_IDEAL = 100;
private static final int MIN_RECORDS_PER_CHUNK = 5;
private static final int SPLIT_RATIO_DEFAULT = 2;
private static int getSplitRatio(Configuration conf) {
int splitRatio = conf.getInt(
DistCpConstants.CONF_LABEL_SPLIT_RATIO,
DistCpConstants.SPLIT_RATIO_DEFAULT);
if (splitRatio <= 0) {
LOG.warn(DistCpConstants.CONF_LABEL_SPLIT_RATIO +
" should be positive. Fall back to default value: "
+ DistCpConstants.SPLIT_RATIO_DEFAULT);
splitRatio = DistCpConstants.SPLIT_RATIO_DEFAULT;
}
return splitRatio;
}
/**
* Package private, for testability.
* @param nMaps The number of maps requested for.
@ -253,19 +302,34 @@ private static int getListingSplitRatio(Configuration configuration,
* @return The number of splits each map should handle, ideally.
*/
static int getSplitRatio(int nMaps, int nRecords) {
return getSplitRatio(nMaps, nRecords,new Configuration());
}
/**
* Package private, for testability.
* @param nMaps The number of maps requested for.
* @param nRecords The number of records to be copied.
* @param conf The configuration set by users.
* @return The number of splits each map should handle, ideally.
*/
static int getSplitRatio(int nMaps, int nRecords, Configuration conf) {
int maxChunksIdeal = getMaxChunksIdeal(conf);
int minRecordsPerChunk = getMinRecordsPerChunk(conf);
int splitRatio = getSplitRatio(conf);
if (nMaps == 1) {
LOG.warn("nMaps == 1. Why use DynamicInputFormat?");
return 1;
}
if (nMaps > MAX_CHUNKS_IDEAL)
return SPLIT_RATIO_DEFAULT;
if (nMaps > maxChunksIdeal)
return splitRatio;
int nPickups = (int)Math.ceil((float)MAX_CHUNKS_IDEAL/nMaps);
int nPickups = (int)Math.ceil((float)maxChunksIdeal/nMaps);
int nRecordsPerChunk = (int)Math.ceil((float)nRecords/(nMaps*nPickups));
return nRecordsPerChunk < MIN_RECORDS_PER_CHUNK ?
SPLIT_RATIO_DEFAULT : nPickups;
return nRecordsPerChunk < minRecordsPerChunk ?
splitRatio : nPickups;
}
static int getNumEntriesPerChunk(Configuration configuration) {

21
hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/mapred/lib/TestDynamicInputFormat.java
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@ -18,6 +18,7 @@
package org.apache.hadoop.tools.mapred.lib;
import org.apache.hadoop.tools.DistCpConstants;
import org.junit.Assert;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
@ -160,5 +161,25 @@ public void testGetSplitRatio() throws Exception {
Assert.assertEquals(2, DynamicInputFormat.getSplitRatio(11000000, 10));
Assert.assertEquals(4, DynamicInputFormat.getSplitRatio(30, 700));
Assert.assertEquals(2, DynamicInputFormat.getSplitRatio(30, 200));
// Tests with negative value configuration
Configuration conf = new Configuration();
conf.setInt(DistCpConstants.CONF_LABEL_MAX_CHUNKS_TOLERABLE, -1);
conf.setInt(DistCpConstants.CONF_LABEL_MAX_CHUNKS_IDEAL, -1);
conf.setInt(DistCpConstants.CONF_LABEL_MIN_RECORDS_PER_CHUNK, -1);
conf.setInt(DistCpConstants.CONF_LABEL_SPLIT_RATIO, -1);
Assert.assertEquals(1,
DynamicInputFormat.getSplitRatio(1, 1000000000, conf));
Assert.assertEquals(2,
DynamicInputFormat.getSplitRatio(11000000, 10, conf));
Assert.assertEquals(4, DynamicInputFormat.getSplitRatio(30, 700, conf));
Assert.assertEquals(2, DynamicInputFormat.getSplitRatio(30, 200, conf));
// Tests with valid configuration
conf.setInt(DistCpConstants.CONF_LABEL_MAX_CHUNKS_TOLERABLE, 100);
conf.setInt(DistCpConstants.CONF_LABEL_MAX_CHUNKS_IDEAL, 30);
conf.setInt(DistCpConstants.CONF_LABEL_MIN_RECORDS_PER_CHUNK, 10);
conf.setInt(DistCpConstants.CONF_LABEL_SPLIT_RATIO, 53);
Assert.assertEquals(53, DynamicInputFormat.getSplitRatio(3, 200, conf));
}
}