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Avoid failing compactions with very large partitions 

Patch by Caleb Rackliffe; Reviewed by Chris Lohfink and Benjamin Lerer for CASSANDRA-15164
This commit is contained in:
Caleb Rackliffe 2020-09-24 10:56:14 -05:00 committed by Chris Lohfink
parent fa7a258f7b
commit 5a39ff4078
7 changed files with 99 additions and 6 deletions
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1
CHANGES.txt
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@ -1,4 +1,5 @@
3.0.23:
* Avoid failing compactions with very large partitions (CASSANDRA-15164)
* Use IF NOT EXISTS for index and UDT create statements in snapshot schema files (CASSANDRA-13935)
3.0.22:

4
src/java/org/apache/cassandra/io/sstable/metadata/MetadataCollector.java
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@ -49,8 +49,8 @@ public class MetadataCollector implements PartitionStatisticsCollector
static EstimatedHistogram defaultCellPerPartitionCountHistogram()
{
// EH of 114 can track a max value of 2395318855, i.e., > 2B columns
return new EstimatedHistogram(114);
// EH of 118 can track a max value of 4139110981, i.e., > 4B cells
return new EstimatedHistogram(118);
}
static EstimatedHistogram defaultPartitionSizeHistogram()

25
src/java/org/apache/cassandra/io/sstable/metadata/StatsMetadata.java
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@ -26,6 +26,9 @@ import org.apache.cassandra.io.ISerializer;
import org.apache.cassandra.io.sstable.format.Version;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.db.TypeSizes;
import org.apache.cassandra.db.commitlog.IntervalSet;
import org.apache.cassandra.db.commitlog.ReplayPosition;
@ -230,6 +233,8 @@ public class StatsMetadata extends MetadataComponent
public static class StatsMetadataSerializer implements IMetadataComponentSerializer<StatsMetadata>
{
private static final Logger logger = LoggerFactory.getLogger(StatsMetadataSerializer.class);
public int serializedSize(Version version, StatsMetadata component) throws IOException
{
int size = 0;
@ -302,9 +307,29 @@ public class StatsMetadata extends MetadataComponent
public StatsMetadata deserialize(Version version, DataInputPlus in) throws IOException
{
EstimatedHistogram partitionSizes = EstimatedHistogram.serializer.deserialize(in);
if (partitionSizes.isOverflowed())
{
logger.warn("Deserialized partition size histogram with {} values greater than the maximum of {}. " +
"Clearing the overflow bucket to allow for degraded mean and percentile calculations...",
partitionSizes.overflowCount(), partitionSizes.getLargestBucketOffset());
partitionSizes.clearOverflow();
}
EstimatedHistogram columnCounts = EstimatedHistogram.serializer.deserialize(in);
if (columnCounts.isOverflowed())
{
logger.warn("Deserialized partition cell count histogram with {} values greater than the maximum of {}. " +
"Clearing the overflow bucket to allow for degraded mean and percentile calculations...",
columnCounts.overflowCount(), columnCounts.getLargestBucketOffset());
columnCounts.clearOverflow();
}
ReplayPosition commitLogLowerBound = ReplayPosition.NONE, commitLogUpperBound;
commitLogUpperBound = ReplayPosition.serializer.deserialize(in);
long minTimestamp = in.readLong();
long maxTimestamp = in.readLong();
// We use MAX_VALUE as that's the default value for "no deletion time"

31
src/java/org/apache/cassandra/utils/EstimatedHistogram.java
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@ -22,12 +22,13 @@ import java.util.Arrays;
import java.util.concurrent.atomic.AtomicLongArray;
import com.google.common.base.Objects;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.db.TypeSizes;
import org.apache.cassandra.io.ISerializer;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.slf4j.Logger;
public class EstimatedHistogram
{
@ -262,11 +263,27 @@ public class EstimatedHistogram
}
/**
* @return true if this histogram has overflowed -- that is, a value larger than our largest bucket could bound was added
* @return true if a value larger than our largest bucket offset has been recorded, and false otherwise
*/
public boolean isOverflowed()
{
return buckets.get(buckets.length() - 1) > 0;
return overflowCount() > 0;
}
/**
* @return the number of recorded values larger than the largest bucket offset
*/
public long overflowCount()
{
return buckets.get(buckets.length() - 1);
}
/**
* Resets the count in the overflow bucket to zero. Subsequent calls to {@link #isOverflowed()} will return false.
*/
public void clearOverflow()
{
buckets.set(buckets.length() - 1, 0);
}
/**
@ -354,8 +371,16 @@ public class EstimatedHistogram
public static class EstimatedHistogramSerializer implements ISerializer<EstimatedHistogram>
{
private static final Logger logger = LoggerFactory.getLogger(EstimatedHistogramSerializer.class);
public void serialize(EstimatedHistogram eh, DataOutputPlus out) throws IOException
{
if (eh.isOverflowed())
{
logger.warn("Serializing a histogram with {} values greater than the maximum of {}...",
eh.overflowCount(), eh.getLargestBucketOffset());
}
long[] offsets = eh.getBucketOffsets();
long[] buckets = eh.getBuckets(false);
out.writeInt(buckets.length);

30
test/unit/org/apache/cassandra/io/sstable/metadata/MetadataSerializerTest.java
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@ -37,6 +37,7 @@ import org.apache.cassandra.db.commitlog.ReplayPosition;
import org.apache.cassandra.dht.RandomPartitioner;
import org.apache.cassandra.io.sstable.Component;
import org.apache.cassandra.io.sstable.Descriptor;
import org.apache.cassandra.io.sstable.format.SSTableFormat;
import org.apache.cassandra.io.sstable.format.Version;
import org.apache.cassandra.io.sstable.format.big.BigFormat;
import org.apache.cassandra.io.util.BufferedDataOutputStreamPlus;
@ -44,6 +45,8 @@ import org.apache.cassandra.io.util.DataOutputStreamPlus;
import org.apache.cassandra.io.util.RandomAccessReader;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class MetadataSerializerTest
{
@ -67,6 +70,33 @@ public class MetadataSerializerTest
}
}
@Test
public void testHistogramSterilization() throws IOException
{
Map<MetadataType, MetadataComponent> originalMetadata = constructMetadata();
// Modify the histograms to overflow:
StatsMetadata originalStats = (StatsMetadata) originalMetadata.get(MetadataType.STATS);
originalStats.estimatedColumnCount.add(Long.MAX_VALUE);
originalStats.estimatedPartitionSize.add(Long.MAX_VALUE);
assertTrue(originalStats.estimatedColumnCount.isOverflowed());
assertTrue(originalStats.estimatedPartitionSize.isOverflowed());
// Serialize w/ overflowed histograms:
MetadataSerializer serializer = new MetadataSerializer();
File statsFile = serialize(originalMetadata, serializer, BigFormat.latestVersion);
Descriptor desc = new Descriptor(statsFile.getParentFile(), "", "", 0, SSTableFormat.Type.BIG);
try (RandomAccessReader in = RandomAccessReader.open(statsFile))
{
// Deserialie and verify that the two histograms have had their overflow buckets cleared:
Map<MetadataType, MetadataComponent> deserialized = serializer.deserialize(desc, in, EnumSet.allOf(MetadataType.class));
StatsMetadata deserializedStats = (StatsMetadata)deserialized.get(MetadataType.STATS);
assertFalse(deserializedStats.estimatedColumnCount.isOverflowed());
assertFalse(deserializedStats.estimatedPartitionSize.isOverflowed());
}
}
public File serialize(Map<MetadataType, MetadataComponent> metadata, MetadataSerializer serializer, Version version)
throws IOException, FileNotFoundException
{

12
test/unit/org/apache/cassandra/utils/EstimatedHistogramTest.java
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@ -21,6 +21,8 @@ package org.apache.cassandra.utils;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class EstimatedHistogramTest
@ -167,4 +169,14 @@ public class EstimatedHistogramTest
assertEquals(1, histogram.percentile(0.99));
}
}
@Test
public void testClearOverflow()
{
EstimatedHistogram histogram = new EstimatedHistogram(1);
histogram.add(100);
assertTrue(histogram.isOverflowed());
histogram.clearOverflow();
assertFalse(histogram.isOverflowed());
}
}

2
test/unit/org/apache/cassandra/utils/SerializationsTest.java
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@ -202,7 +202,7 @@ public class SerializationsTest extends AbstractSerializationsTester
offsets[i] = i;
data[i] = 10 * i;
}
data[offsets.length] = 100000;
data[offsets.length] = 100000; // write into the overflow bucket
EstimatedHistogram hist2 = new EstimatedHistogram(offsets, data);
try (DataOutputStreamPlus out = getOutput("utils.EstimatedHistogram.bin"))