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Avoid checking isSplittable for files smaller than initial split size
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For some input formats, the isSplittable check is non-trivial and can
add a significant amount of time to split generation when handling a
large number of very small files. This change allows files smaller
than the max initial split size to avoid that check and considers them
unsplittable instead.
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@pettyjamesm @electrum
pettyjamesm authored and electrum committed Jul 27, 2020
1 parent e6c960e commit 2cf1ca3
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Showing 3 changed files with 92 additions and 8 deletions.
3 changes: 3 additions & 0 deletions presto-hive/src/main/java/io/prestosql/plugin/hive/BackgroundHiveSplitLoader.java
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Expand Up @@ -89,6 +89,7 @@
import static io.prestosql.plugin.hive.HiveErrorCode.HIVE_INVALID_PARTITION_VALUE;
import static io.prestosql.plugin.hive.HiveErrorCode.HIVE_UNKNOWN_ERROR;
import static io.prestosql.plugin.hive.HivePartitionManager.partitionMatches;
import static io.prestosql.plugin.hive.HiveSessionProperties.getMaxInitialSplitSize;
import static io.prestosql.plugin.hive.HiveSessionProperties.isForceLocalScheduling;
import static io.prestosql.plugin.hive.metastore.MetastoreUtil.getHiveSchema;
import static io.prestosql.plugin.hive.metastore.MetastoreUtil.getPartitionLocation;
Expand Down Expand Up @@ -375,6 +376,7 @@ private ListenableFuture<?> loadPartition(HivePartitionMetadata partition)
partitionMatchSupplier,
partition.getTableToPartitionMapping(),
Optional.empty(),
getMaxInitialSplitSize(session),
isForceLocalScheduling(session),
s3SelectPushdownEnabled);
lastResult = addSplitsToSource(targetSplits, splitFactory);
Expand Down Expand Up @@ -413,6 +415,7 @@ private ListenableFuture<?> loadPartition(HivePartitionMetadata partition)
partitionMatchSupplier,
partition.getTableToPartitionMapping(),
bucketConversionRequiresWorkerParticipation ? bucketConversion : Optional.empty(),
getMaxInitialSplitSize(session),
isForceLocalScheduling(session),
s3SelectPushdownEnabled);

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9 changes: 8 additions & 1 deletion presto-hive/src/main/java/io/prestosql/plugin/hive/util/InternalHiveSplitFactory.java
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Expand Up @@ -14,6 +14,7 @@
package io.prestosql.plugin.hive.util;

import com.google.common.collect.ImmutableList;
import io.airlift.units.DataSize;
import io.prestosql.plugin.hive.AcidInfo;
import io.prestosql.plugin.hive.HiveColumnHandle;
import io.prestosql.plugin.hive.HivePartitionKey;
Expand Down Expand Up @@ -62,6 +63,7 @@ public class InternalHiveSplitFactory
private final TableToPartitionMapping tableToPartitionMapping;
private final BooleanSupplier partitionMatchSupplier;
private final Optional<BucketConversion> bucketConversion;
private final long minimumTargetSplitSizeInBytes;
private final boolean forceLocalScheduling;
private final boolean s3SelectPushdownEnabled;

Expand All @@ -75,6 +77,7 @@ public InternalHiveSplitFactory(
BooleanSupplier partitionMatchSupplier,
TableToPartitionMapping tableToPartitionMapping,
Optional<BucketConversion> bucketConversion,
DataSize minimumTargetSplitSize,
boolean forceLocalScheduling,
boolean s3SelectPushdownEnabled)
{
Expand All @@ -89,6 +92,8 @@ public InternalHiveSplitFactory(
this.bucketConversion = requireNonNull(bucketConversion, "bucketConversion is null");
this.forceLocalScheduling = forceLocalScheduling;
this.s3SelectPushdownEnabled = s3SelectPushdownEnabled;
this.minimumTargetSplitSizeInBytes = requireNonNull(minimumTargetSplitSize, "minimumTargetSplitSize is null").toBytes();
checkArgument(minimumTargetSplitSizeInBytes > 0, "minimumTargetSplitSize must be > 0, found: %s", minimumTargetSplitSize);
}

public String getPartitionName()
Expand All @@ -98,7 +103,9 @@ public String getPartitionName()

public Optional<InternalHiveSplit> createInternalHiveSplit(LocatedFileStatus status, OptionalInt bucketNumber, boolean splittable, Optional<AcidInfo> acidInfo)
{
splittable = splittable && isSplittable(inputFormat, fileSystem, status.getPath());
splittable = splittable &&
status.getLen() > minimumTargetSplitSizeInBytes &&
isSplittable(inputFormat, fileSystem, status.getPath());
return createInternalHiveSplit(
status.getPath(),
status.getBlockLocations(),
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88 changes: 81 additions & 7 deletions presto-hive/src/test/java/io/prestosql/plugin/hive/TestBackgroundHiveSplitLoader.java
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Expand Up @@ -13,6 +13,7 @@
*/
package io.prestosql.plugin.hive;

import com.google.common.base.Throwables;
import com.google.common.collect.AbstractIterator;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.ImmutableList;
Expand Down Expand Up @@ -46,6 +47,12 @@
import org.apache.hadoop.hive.common.ValidReaderWriteIdList;
import org.apache.hadoop.hive.common.ValidWriteIdList;
import org.apache.hadoop.hive.metastore.TableType;
import org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.util.Progressable;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
Expand Down Expand Up @@ -82,6 +89,7 @@
import static io.prestosql.plugin.hive.HiveColumnHandle.createBaseColumn;
import static io.prestosql.plugin.hive.HiveColumnHandle.pathColumnHandle;
import static io.prestosql.plugin.hive.HiveErrorCode.HIVE_INVALID_BUCKET_FILES;
import static io.prestosql.plugin.hive.HiveSessionProperties.getMaxInitialSplitSize;
import static io.prestosql.plugin.hive.HiveStorageFormat.CSV;
import static io.prestosql.plugin.hive.HiveTestUtils.HDFS_ENVIRONMENT;
import static io.prestosql.plugin.hive.HiveTestUtils.SESSION;
Expand All @@ -105,6 +113,7 @@
import static org.testng.Assert.assertFalse;
import static org.testng.Assert.assertThrows;
import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;

public class TestBackgroundHiveSplitLoader
{
Expand Down Expand Up @@ -156,14 +165,79 @@ public void testNoPathFilter()
public void testCsv()
throws Exception
{
assertSplitCount(CSV, ImmutableMap.of(), 33);
assertSplitCount(CSV, ImmutableMap.of("skip.header.line.count", "1"), 33);
assertSplitCount(CSV, ImmutableMap.of("skip.header.line.count", "2"), 1);
assertSplitCount(CSV, ImmutableMap.of("skip.footer.line.count", "1"), 1);
assertSplitCount(CSV, ImmutableMap.of("skip.header.line.count", "1", "skip.footer.line.count", "1"), 1);
DataSize fileSize = DataSize.of(2, GIGABYTE);
assertSplitCount(CSV, ImmutableMap.of(), fileSize, 33);
assertSplitCount(CSV, ImmutableMap.of("skip.header.line.count", "1"), fileSize, 33);
assertSplitCount(CSV, ImmutableMap.of("skip.header.line.count", "2"), fileSize, 1);
assertSplitCount(CSV, ImmutableMap.of("skip.footer.line.count", "1"), fileSize, 1);
assertSplitCount(CSV, ImmutableMap.of("skip.header.line.count", "1", "skip.footer.line.count", "1"), fileSize, 1);
}

private void assertSplitCount(HiveStorageFormat storageFormat, Map<String, String> tableProperties, int expectedSplitCount)
@Test
public void testSplittableNotCheckedOnSmallFiles()
throws Exception
{
DataSize initialSplitSize = getMaxInitialSplitSize(SESSION);

Table table = table(
ImmutableList.of(),
Optional.empty(),
ImmutableMap.of(),
StorageFormat.create(LazySimpleSerDe.class.getName(), TestSplittableFailureInputFormat.class.getName(), TestSplittableFailureInputFormat.class.getName()));

// Exactly minimum split size, no isSplittable check
BackgroundHiveSplitLoader backgroundHiveSplitLoader = backgroundHiveSplitLoader(
ImmutableList.of(locatedFileStatus(new Path(SAMPLE_PATH), initialSplitSize.toBytes())),
TupleDomain.all(),
Optional.empty(),
table,
Optional.empty());

HiveSplitSource hiveSplitSource = hiveSplitSource(backgroundHiveSplitLoader);
backgroundHiveSplitLoader.start(hiveSplitSource);

assertEquals(drainSplits(hiveSplitSource).size(), 1);

// Large enough for isSplittable to be called
backgroundHiveSplitLoader = backgroundHiveSplitLoader(
ImmutableList.of(locatedFileStatus(new Path(SAMPLE_PATH), initialSplitSize.toBytes() + 1)),
TupleDomain.all(),
Optional.empty(),
table,
Optional.empty());

hiveSplitSource = hiveSplitSource(backgroundHiveSplitLoader);
backgroundHiveSplitLoader.start(hiveSplitSource);

try {
drainSplits(hiveSplitSource);
fail("Expected split generation to call isSplittable and fail");
}
catch (PrestoException e) {
Throwable cause = Throwables.getRootCause(e);
assertTrue(cause instanceof IllegalStateException);
assertEquals(cause.getMessage(), "isSplittable called");
}
}

public static final class TestSplittableFailureInputFormat
extends FileInputFormat<Void, Void>
{
@Override
protected boolean isSplitable(FileSystem fs, Path filename)
{
throw new IllegalStateException("isSplittable called");
}

@Override
public RecordReader<Void, Void> getRecordReader(InputSplit inputSplit, JobConf jobConf, Reporter reporter)
throws IOException
{
throw new UnsupportedOperationException();
}
}

private void assertSplitCount(HiveStorageFormat storageFormat, Map<String, String> tableProperties, DataSize fileSize, int expectedSplitCount)
throws Exception
{
Table table = table(
Expand All @@ -173,7 +247,7 @@ private void assertSplitCount(HiveStorageFormat storageFormat, Map<String, Strin
StorageFormat.fromHiveStorageFormat(storageFormat));

BackgroundHiveSplitLoader backgroundHiveSplitLoader = backgroundHiveSplitLoader(
ImmutableList.of(locatedFileStatus(new Path(SAMPLE_PATH), DataSize.of(2, GIGABYTE).toBytes())),
ImmutableList.of(locatedFileStatus(new Path(SAMPLE_PATH), fileSize.toBytes())),
TupleDomain.all(),
Optional.empty(),
table,
Expand Down

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