natas_hw
/
cassandra
mirror of https://github.com/apache/cassandra
0
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

[CASSANDRA-21536] Profile pollution in AbstractType.writeValue makes serialization slow for all column types 

Description:
AbstractType.writeValue() is one shared method. All column types use it.

Inside writeValue(), it calls valueLengthIfFixed(). This is a virtual call. Many types override this method (Int32Type, LongType, UTF8Type, ...).

In a real cluster, many column types pass through writeValue(). So the profile always sees lots types.

Because of this, the JIT cannot inline the call. It stays as a vtable call. Also, the compiled body of writeValue() becomes big, so the JIT refuses to inline writeValue() itself ("already compiled into a big method").

We also see the same itable/vtable stubs in async-profiler output from a real cluster, running with default production options and a normal workload.

How to solve:
Add a final int field to AbstractType. Set it in the constructor. writeValue() reads this field instead of calling valueLengthIfFixed().

A field read needs no type profile. So profile pollution has no effect on it. The valueLengthIfFixed() method is not changed. Only the write path uses the field.

Result:
Production is always the polluted state, so this is the real-world comparison

 JMH, JDK 17 / arm64, 1 thread, 10 x 1s warmup and measurement:

                    before          after       improvement
   readValue        49.99M ops/s    56.44M ops/s  +12.90%
   writeValue       99.63M ops/s   114.46M ops/s  +14.88%

patch by Koo Taejin; reviewed by Dmitry Konstantinov, Francisco Guerrero for CASSANDRA-21536
This commit is contained in:
koo.taejin 2026-07-27 23:48:03 +09:00 committed by Francisco Guerrero
parent 725c61c1f7
commit aa1447571b
20 changed files with 149 additions and 103 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
CHANGES.txt
View File

@ -1,4 +1,5 @@
6.0-alpha2
* Avoid megamorphic calls when serializing and deserializing fixed-length values (CASSANDRA-21536)
* Avoid megamorphic calls for Cell.timestamp/ttl/path/localDeletionTimeAsUnsignedInt methods (CASSANDRA-21526)
* Allow unreserved keywords as user and identity names in USER and IDENTITY statements (CASSANDRA-21510)
* Reduce allocations in DefaultQueryOptions (CASSANDRA-21467)

8
src/java/org/apache/cassandra/db/marshal/AbstractTimeUUIDType.java
View File

@ -39,7 +39,7 @@ public abstract class AbstractTimeUUIDType<T> extends TemporalType<T>
{
AbstractTimeUUIDType()
{
super(ComparisonType.CUSTOM);
super(ComparisonType.CUSTOM, 16);
} // singleton
@Override
@ -193,12 +193,6 @@ public abstract class AbstractTimeUUIDType<T> extends TemporalType<T>
return super.decomposeUntyped(value);
}
@Override
public int valueLengthIfFixed()
{
return 16;
}
@Override
public long toTimeInMillis(ByteBuffer value)
{

27
src/java/org/apache/cassandra/db/marshal/AbstractType.java
View File

@ -90,11 +90,18 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
public final ComparisonType comparisonType;
public final boolean isByteOrderComparable;
public final ValueComparators comparatorSet;
private final int valueLengthIfFixed;
protected AbstractType(ComparisonType comparisonType)
{
this(comparisonType, VARIABLE_LENGTH);
}
protected AbstractType(ComparisonType comparisonType, int valueLengthIfFixed)
{
this.comparisonType = comparisonType;
this.isByteOrderComparable = comparisonType == ComparisonType.BYTE_ORDER;
this.valueLengthIfFixed = valueLengthIfFixed;
reverseComparator = (o1, o2) -> AbstractType.this.compare(o2, o1);
try
{
@ -384,12 +391,12 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
/**
* Similar to {@link #isValueCompatibleWith(AbstractType)}, but takes into account {@link Cell} encoding.
* In particular, this method doesn't consider two types serialization compatible if one of them has fixed
* length (overrides {@link #valueLengthIfFixed()}, and the other one doesn't.
* length, and the other one doesn't.
*/
public boolean isSerializationCompatibleWith(AbstractType<?> previous)
{
return isValueCompatibleWith(previous)
&& valueLengthIfFixed() == previous.valueLengthIfFixed()
&& valueLengthIfFixed == previous.valueLengthIfFixed
&& isMultiCell() == previous.isMultiCell();
}
@ -498,7 +505,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
*/
public int valueLengthIfFixed()
{
return VARIABLE_LENGTH;
return valueLengthIfFixed;
}
/**
@ -508,7 +515,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
*/
public final boolean isValueLengthFixed()
{
return valueLengthIfFixed() != VARIABLE_LENGTH;
return valueLengthIfFixed != VARIABLE_LENGTH;
}
/**
@ -570,7 +577,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
public <V> void writeValue(V value, ValueAccessor<V> accessor, DataOutputPlus out) throws IOException
{
assert !isNull(value, accessor) : "bytes should not be null for type " + this;
int expectedValueLength = valueLengthIfFixed();
int expectedValueLength = valueLengthIfFixed;
if (expectedValueLength >= 0)
{
int actualValueLength = accessor.size(value);
@ -589,7 +596,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
public <V> void writeValue(IndexedValueHolder<V> valueHolder, int i, ValueAccessor<V> accessor, DataOutputPlus out) throws IOException
{
assert !valueHolder.isNull(i) : "bytes should not be null for type " + this;
int expectedValueLength = valueLengthIfFixed();
int expectedValueLength = valueLengthIfFixed;
if (expectedValueLength >= 0)
{
int actualValueLength = valueHolder.size(i);
@ -613,7 +620,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
public <V> long writtenLength(V value, ValueAccessor<V> accessor)
{
assert !accessor.isEmpty(value) : "bytes should not be empty for type " + this;
return valueLengthIfFixed() >= 0
return valueLengthIfFixed >= 0
? accessor.size(value) // if the size is wrong, this will be detected in writeValue
: accessor.sizeWithVIntLength(value);
}
@ -621,7 +628,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
public <V> long writtenLength(IndexedValueHolder<V> valueHolder, int i, ValueAccessor<V> accessor)
{
assert !valueHolder.isNull(i) : "bytes should not be null for type " + this;
return valueLengthIfFixed() >= 0
return valueLengthIfFixed >= 0
? valueHolder.size(i) // if the size is wrong, this will be detected in writeValue
: accessor.sizeWithVIntLength(valueHolder, i);
}
@ -643,7 +650,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
public <V> V read(ValueAccessor<V> accessor, DataInputPlus in, int maxValueSize) throws IOException
{
int length = valueLengthIfFixed();
int length = valueLengthIfFixed;
if (length >= 0)
return accessor.read(in, length);
@ -664,7 +671,7 @@ public abstract class AbstractType<T> implements Comparator<ByteBuffer>, Assignm
public void skipValue(DataInputPlus in) throws IOException
{
int length = valueLengthIfFixed();
int length = valueLengthIfFixed;
if (length >= 0)
in.skipBytesFully(length);
else

8
src/java/org/apache/cassandra/db/marshal/BooleanType.java
View File

@ -36,7 +36,7 @@ public class BooleanType extends AbstractType<Boolean>
private static final ArgumentDeserializer ARGUMENT_DESERIALIZER = new DefaultArgumentDeserializer(instance);
private static final ByteBuffer MASKED_VALUE = instance.decompose(false);
BooleanType() {super(ComparisonType.CUSTOM);} // singleton
BooleanType() {super(ComparisonType.CUSTOM, 1);} // singleton
@Override
public boolean allowsEmpty()
@ -127,12 +127,6 @@ public class BooleanType extends AbstractType<Boolean>
return ARGUMENT_DESERIALIZER;
}
@Override
public int valueLengthIfFixed()
{
return 1;
}
@Override
public ByteBuffer getMaskedValue()
{

8
src/java/org/apache/cassandra/db/marshal/DateType.java
View File

@ -49,7 +49,7 @@ public class DateType extends AbstractType<Date>
private static final ArgumentDeserializer ARGUMENT_DESERIALIZER = new DefaultArgumentDeserializer(instance);
private static final ByteBuffer MASKED_VALUE = instance.decompose(new Date(0));
DateType() {super(ComparisonType.BYTE_ORDER);} // singleton
DateType() {super(ComparisonType.BYTE_ORDER, 8);} // singleton
public boolean isEmptyValueMeaningless()
{
@ -143,12 +143,6 @@ public class DateType extends AbstractType<Date>
return ARGUMENT_DESERIALIZER;
}
@Override
public int valueLengthIfFixed()
{
return 8;
}
@Override
public ByteBuffer getMaskedValue()
{

8
src/java/org/apache/cassandra/db/marshal/DoubleType.java
View File

@ -40,7 +40,7 @@ public class DoubleType extends NumberType<Double>
private static final ByteBuffer MASKED_VALUE = instance.decompose(0d);
DoubleType() {super(ComparisonType.CUSTOM);} // singleton
DoubleType() {super(ComparisonType.CUSTOM, 8);} // singleton
@Override
public boolean allowsEmpty()
@ -145,12 +145,6 @@ public class DoubleType extends NumberType<Double>
};
}
@Override
public int valueLengthIfFixed()
{
return 8;
}
@Override
public ByteBuffer add(Number left, Number right)
{

8
src/java/org/apache/cassandra/db/marshal/EmptyType.java
View File

@ -71,7 +71,7 @@ public class EmptyType extends AbstractType<Void>
public static final EmptyType instance = new EmptyType();
private EmptyType() {super(ComparisonType.CUSTOM);} // singleton
private EmptyType() {super(ComparisonType.CUSTOM, 0);} // singleton
@Override
public <V> ByteSource asComparableBytes(ValueAccessor<V> accessor, V data, ByteComparable.Version version)
@ -137,12 +137,6 @@ public class EmptyType extends AbstractType<Void>
throw new UnsupportedOperationException();
}
@Override
public int valueLengthIfFixed()
{
return 0;
}
@Override
public <V> long writtenLength(V value, ValueAccessor<V> accessor)
{

8
src/java/org/apache/cassandra/db/marshal/FloatType.java
View File

@ -41,7 +41,7 @@ public class FloatType extends NumberType<Float>
private static final ByteBuffer MASKED_VALUE = instance.decompose(0f);
FloatType() {super(ComparisonType.CUSTOM);} // singleton
FloatType() {super(ComparisonType.CUSTOM, 4);} // singleton
@Override
public boolean allowsEmpty()
@ -146,12 +146,6 @@ public class FloatType extends NumberType<Float>
};
}
@Override
public int valueLengthIfFixed()
{
return 4;
}
@Override
public ByteBuffer add(Number left, Number right)
{

8
src/java/org/apache/cassandra/db/marshal/Int32Type.java
View File

@ -43,7 +43,7 @@ public class Int32Type extends NumberType<Integer>
Int32Type()
{
super(ComparisonType.CUSTOM);
super(ComparisonType.CUSTOM, 4);
} // singleton
@Override
@ -152,12 +152,6 @@ public class Int32Type extends NumberType<Integer>
};
}
@Override
public int valueLengthIfFixed()
{
return 4;
}
@Override
public ByteBuffer add(Number left, Number right)
{

8
src/java/org/apache/cassandra/db/marshal/LexicalUUIDType.java
View File

@ -44,7 +44,7 @@ public class LexicalUUIDType extends AbstractType<UUID>
LexicalUUIDType()
{
super(ComparisonType.CUSTOM);
super(ComparisonType.CUSTOM, 16);
} // singleton
@Override
@ -148,12 +148,6 @@ public class LexicalUUIDType extends AbstractType<UUID>
return ARGUMENT_DESERIALIZER;
}
@Override
public int valueLengthIfFixed()
{
return 16;
}
@Override
public ByteBuffer getMaskedValue()
{

8
src/java/org/apache/cassandra/db/marshal/LongType.java
View File

@ -41,7 +41,7 @@ public class LongType extends NumberType<Long>
private static final ByteBuffer MASKED_VALUE = instance.decompose(0L);
LongType() {super(ComparisonType.CUSTOM);} // singleton
LongType() {super(ComparisonType.CUSTOM, 8);} // singleton
@Override
public boolean allowsEmpty()
@ -170,12 +170,6 @@ public class LongType extends NumberType<Long>
};
}
@Override
public int valueLengthIfFixed()
{
return 8;
}
@Override
public ByteBuffer add(Number left, Number right)
{

6
src/java/org/apache/cassandra/db/marshal/MultiElementType.java
View File

@ -38,6 +38,11 @@ public abstract class MultiElementType<T> extends AbstractType<T>
super(comparisonType);
}
protected MultiElementType(ComparisonType comparisonType, int valueLengthIfFixed)
{
super(comparisonType, valueLengthIfFixed);
}
/**
* Returns the serialized representation of the value composed of the specified elements.
*
@ -133,4 +138,3 @@ public abstract class MultiElementType<T> extends AbstractType<T>
throw new UnsupportedOperationException(this + " does not support retrieving elements by key or index");
}
}

5
src/java/org/apache/cassandra/db/marshal/NumberType.java
View File

@ -34,6 +34,11 @@ public abstract class NumberType<T extends Number> extends AbstractType<T>
super(comparisonType);
}
protected NumberType(ComparisonType comparisonType, int valueLengthIfFixed)
{
super(comparisonType, valueLengthIfFixed);
}
/**
* Checks if this type support floating point numbers.
* @return {@code true} if this type support floating point numbers, {@code false} otherwise.

8
src/java/org/apache/cassandra/db/marshal/ReversedType.java
View File

@ -57,7 +57,7 @@ public class ReversedType<T> extends AbstractType<T>
private ReversedType(AbstractType<T> baseType)
{
super(ComparisonType.CUSTOM);
super(ComparisonType.CUSTOM, baseType.valueLengthIfFixed());
this.baseType = baseType;
}
@ -181,12 +181,6 @@ public class ReversedType<T> extends AbstractType<T>
return getInstance(baseType.withUpdatedUserType(udt));
}
@Override
public int valueLengthIfFixed()
{
return baseType.valueLengthIfFixed();
}
@Override
public boolean isReversed()
{

5
src/java/org/apache/cassandra/db/marshal/TemporalType.java
View File

@ -37,6 +37,11 @@ public abstract class TemporalType<T> extends AbstractType<T>
super(comparisonType);
}
protected TemporalType(ComparisonType comparisonType, int valueLengthIfFixed)
{
super(comparisonType, valueLengthIfFixed);
}
/**
* Returns the current temporal value.
* @return the current temporal value.

8
src/java/org/apache/cassandra/db/marshal/TimestampType.java
View File

@ -53,7 +53,7 @@ public class TimestampType extends TemporalType<Date>
private static final ByteBuffer MASKED_VALUE = instance.decompose(new Date(0));
private TimestampType() {super(ComparisonType.CUSTOM);} // singleton
private TimestampType() {super(ComparisonType.CUSTOM, 8);} // singleton
@Override
public boolean allowsEmpty()
@ -166,12 +166,6 @@ public class TimestampType extends TemporalType<Date>
return TimestampSerializer.instance;
}
@Override
public int valueLengthIfFixed()
{
return 8;
}
@Override
protected void validateDuration(Duration duration)
{

8
src/java/org/apache/cassandra/db/marshal/UUIDType.java
View File

@ -56,7 +56,7 @@ public class UUIDType extends AbstractType<UUID>
UUIDType()
{
super(ComparisonType.CUSTOM);
super(ComparisonType.CUSTOM, 16);
}
@Override
@ -252,12 +252,6 @@ public class UUIDType extends AbstractType<UUID>
return (uuid.get(6) & 0xf0) >> 4;
}
@Override
public int valueLengthIfFixed()
{
return 16;
}
@Override
public ByteBuffer getMaskedValue()
{

12
src/java/org/apache/cassandra/db/marshal/VectorType.java
View File

@ -82,20 +82,16 @@ public final class VectorType<T> extends MultiElementType<List<T>>
public final AbstractType<T> elementType;
public final int dimension;
private final TypeSerializer<T> elementSerializer;
private final int valueLengthIfFixed;
private final VectorSerializer serializer;
private VectorType(AbstractType<T> elementType, int dimension)
{
super(ComparisonType.CUSTOM);
super(ComparisonType.CUSTOM, valueLengthIfFixed(elementType, dimension));
if (dimension <= 0)
throw new InvalidRequestException(String.format("vectors may only have positive dimensions; given %d", dimension));
this.elementType = elementType;
this.dimension = dimension;
this.elementSerializer = elementType.getSerializer();
this.valueLengthIfFixed = elementType.isValueLengthFixed() ?
elementType.valueLengthIfFixed() * dimension :
super.valueLengthIfFixed();
this.serializer = elementType.isValueLengthFixed() ?
new FixedLengthSerializer() :
new VariableLengthSerializer();
@ -126,10 +122,10 @@ public final class VectorType<T> extends MultiElementType<List<T>>
return getSerializer().compareCustom(left, accessorL, right, accessorR);
}
@Override
public int valueLengthIfFixed()
private static int valueLengthIfFixed(AbstractType<?> elementType, int dimension)
{
return valueLengthIfFixed;
int elementLength = elementType.valueLengthIfFixed();
return elementLength >= 0 ? elementLength * dimension : elementLength;
}
@Override

94
test/microbench/org/apache/cassandra/test/microbench/AbstractTypeSerializationBench.java Normal file
View File

@ -0,0 +1,94 @@
/*
* 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.cassandra.test.microbench;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.concurrent.TimeUnit;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Threads;
import org.openjdk.jmh.annotations.Warmup;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.db.marshal.BooleanType;
import org.apache.cassandra.db.marshal.Int32Type;
import org.apache.cassandra.db.marshal.LongType;
import org.apache.cassandra.db.marshal.UTF8Type;
import org.apache.cassandra.db.marshal.UUIDType;
import org.apache.cassandra.io.util.DataInputBuffer;
import org.apache.cassandra.io.util.DataOutputBuffer;
import org.apache.cassandra.utils.ByteBufferUtil;
/**
* Measures value serialization when one call site sees the fixed- and variable-width types commonly used by a table.
*/
@BenchmarkMode(Mode.Throughput)
@OutputTimeUnit(TimeUnit.SECONDS)
@Warmup(iterations = 5, time = 1)
@Measurement(iterations = 5, time = 1)
@Fork(value = 1, jvmArgsAppend = { "-Xmx1G", "-Djmh.executor=CUSTOM", "-Djmh.executor.class=org.apache.cassandra.test.microbench.FastThreadExecutor" })
@Threads(1)
@State(Scope.Thread)
public class AbstractTypeSerializationBench
{
private final AbstractType<?>[] types = { Int32Type.instance, LongType.instance, BooleanType.instance, UUIDType.instance,
UTF8Type.instance, Int32Type.instance, LongType.instance, UTF8Type.instance };
private final ByteBuffer[] values = { ByteBufferUtil.bytes(42), ByteBufferUtil.bytes(42L), ByteBuffer.wrap(new byte[] { 1 }),
ByteBuffer.wrap(new byte[16]), ByteBufferUtil.bytes("cassandra"), ByteBufferUtil.bytes(42),
ByteBufferUtil.bytes(42L), ByteBufferUtil.bytes("cassandra") };
private final ByteBuffer[] serializedValues = new ByteBuffer[types.length];
private final DataOutputBuffer out = new DataOutputBuffer();
private int index;
@Setup
public void setup() throws IOException
{
for (int i = 0; i < types.length; i++)
{
out.clear();
types[i].writeValue(values[i], out);
serializedValues[i] = out.asNewBuffer();
}
}
@Benchmark
public int writeValue() throws IOException
{
int i = index++ & (types.length - 1);
out.clear();
types[i].writeValue(values[i], out);
return out.getLength();
}
@Benchmark
public ByteBuffer readValue() throws IOException
{
int i = index++ & (types.length - 1);
return types[i].readBuffer(new DataInputBuffer(serializedValues[i], true));
}
}

6
test/unit/org/apache/cassandra/db/marshal/AbstractTypeTest.java
View File

@ -739,6 +739,12 @@ public class AbstractTypeTest
}});
}
@Test
public void valueLengthIfFixedIsNotFinal() throws NoSuchMethodException
{
assertThat(Modifier.isFinal(AbstractType.class.getMethod("valueLengthIfFixed").getModifiers())).isFalse();
}
@Test
@SuppressWarnings({"rawtypes", "unchecked"})
public void serde()