Skip to content

Reduce weighing overhead for caching blocks #36897

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: master
Choose a base branch
from
Open

Reduce weighing overhead for caching blocks #36897

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
e904467
Reduce weighing overhead for caching blocks
scwhittle Nov 25, 2025
827af2f
fix imports
scwhittle Nov 25, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 2 additions & 9 deletions sdks/java/core/src/main/java/org/apache/beam/sdk/fn/data/WeightedList.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.beam.sdk.util.Weighted;
import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.math.LongMath;

/** Facade for a {@link List<T>} that keeps track of weight, for cache limit reasons. */
public class WeightedList<T> implements Weighted {
Expand Down Expand Up @@ -71,14 +72,6 @@ public void addAll(List<T> values, long weight) {
}

public void accumulateWeight(long weight) {
this.weight.accumulateAndGet(
weight,
(first, second) -> {
try {
return Math.addExact(first, second);
} catch (ArithmeticException e) {
return Long.MAX_VALUE;
}
});
this.weight.accumulateAndGet(weight, LongMath::saturatedAdd);
}
}
81 changes: 51 additions & 30 deletions sdks/java/harness/src/main/java/org/apache/beam/fn/harness/state/StateFetchingIterators.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -45,10 +45,12 @@
import org.apache.beam.sdk.fn.stream.PrefetchableIterables;
import org.apache.beam.sdk.fn.stream.PrefetchableIterator;
import org.apache.beam.sdk.util.Weighted;
import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.math.LongMath;
import org.apache.beam.vendor.grpc.v1p69p0.com.google.protobuf.ByteString;
import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.annotations.VisibleForTesting;
import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Throwables;
import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.AbstractIterator;
import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;

/**
* Adapters which convert a logical series of chunks using continuation tokens over the Beam Fn
Expand Down Expand Up @@ -249,15 +251,11 @@ static class BlocksPrefix<T> extends Blocks<T> implements Shrinkable<BlocksPrefi

@Override
public long getWeight() {
try {
long sum = 8 + blocks.size() * 8L;
for (Block<T> block : blocks) {
sum = Math.addExact(sum, block.getWeight());
}
return sum;
} catch (ArithmeticException e) {
return Long.MAX_VALUE;
long sum = 8 + blocks.size() * 8L;
for (Block<T> block : blocks) {
sum = LongMath.saturatedAdd(sum, block.getWeight());
}
return sum;
}

BlocksPrefix(List<Block<T>> blocks) {
Expand All @@ -282,8 +280,7 @@ public List<Block<T>> getBlocks() {

@AutoValue
abstract static class Block<T> implements Weighted {
private static final Block<Void> EMPTY =
fromValues(WeightedList.of(Collections.emptyList(), 0), null);
private static final Block<Void> EMPTY = fromValues(ImmutableList.of(), 0, null);

@SuppressWarnings("unchecked") // Based upon as Collections.emptyList()
public static <T> Block<T> emptyBlock() {
Expand All @@ -299,21 +296,37 @@ public static <T> Block<T> mutatedBlock(WeightedList<T> values) {
}

public static <T> Block<T> fromValues(List<T> values, @Nullable ByteString nextToken) {
return fromValues(WeightedList.of(values, Caches.weigh(values)), nextToken);
if (values.isEmpty() && nextToken == null) {
return emptyBlock();
}
ImmutableList<T> immutableValues = ImmutableList.copyOf(values);
long listWeight = immutableValues.size() * Caches.REFERENCE_SIZE;
for (T value : immutableValues) {
listWeight = LongMath.saturatedAdd(listWeight, Caches.weigh(value));
}
return fromValues(immutableValues, listWeight, nextToken);
}

public static <T> Block<T> fromValues(
WeightedList<T> values, @Nullable ByteString nextToken) {
long weight = values.getWeight() + 24;
if (values.isEmpty() && nextToken == null) {
return emptyBlock();
}
return fromValues(ImmutableList.copyOf(values.getBacking()), values.getWeight(), nextToken);
}

private static <T> Block<T> fromValues(
ImmutableList<T> values, long listWeight, @Nullable ByteString nextToken) {
long weight = LongMath.saturatedAdd(listWeight, 24);
if (nextToken != null) {
if (nextToken.isEmpty()) {
nextToken = ByteString.EMPTY;
} else {
weight += Caches.weigh(nextToken);
weight = LongMath.saturatedAdd(weight, Caches.weigh(nextToken));
}
}
return new AutoValue_StateFetchingIterators_CachingStateIterable_Block<>(
values.getBacking(), nextToken, weight);
values, nextToken, weight);
}

abstract List<T> getValues();
Expand Down Expand Up @@ -372,10 +385,12 @@ public void remove(Set<Object> toRemoveStructuralValues) {
totalSize += tBlock.getValues().size();
}

WeightedList<T> allValues = WeightedList.of(new ArrayList<>(totalSize), 0L);
ImmutableList.Builder<T> allValues = ImmutableList.builderWithExpectedSize(totalSize);
long weight = 0;
List<T> blockValuesToKeep = new ArrayList<>();
for (Block<T> block : blocks) {
blockValuesToKeep.clear();
boolean valueRemovedFromBlock = false;
List<T> blockValuesToKeep = new ArrayList<>();
for (T value : block.getValues()) {
if (!toRemoveStructuralValues.contains(valueCoder.structuralValue(value))) {
blockValuesToKeep.add(value);
Expand All @@ -387,13 +402,19 @@ public void remove(Set<Object> toRemoveStructuralValues) {
// If any value was removed from this block, need to estimate the weight again.
// Otherwise, just reuse the block's weight.
if (valueRemovedFromBlock) {
allValues.addAll(blockValuesToKeep, Caches.weigh(block.getValues()));
allValues.addAll(blockValuesToKeep);
for (T value : blockValuesToKeep) {
weight = LongMath.saturatedAdd(weight, Caches.weigh(value));
}
} else {
allValues.addAll(block.getValues(), block.getWeight());
allValues.addAll(block.getValues());
weight = LongMath.saturatedAdd(weight, block.getWeight());
}
}

cache.put(IterableCacheKey.INSTANCE, new MutatedBlocks<>(Block.mutatedBlock(allValues)));
cache.put(
IterableCacheKey.INSTANCE,
new MutatedBlocks<>(Block.fromValues(allValues.build(), weight, null)));
}

/**
Expand Down Expand Up @@ -484,21 +505,22 @@ private void appendHelper(List<T> newValues, long newWeight) {
for (Block<T> block : blocks) {
totalSize += block.getValues().size();
}
WeightedList<T> allValues = WeightedList.of(new ArrayList<>(totalSize), 0L);
ImmutableList.Builder<T> allValues = ImmutableList.builderWithExpectedSize(totalSize);
long weight = 0;
for (Block<T> block : blocks) {
allValues.addAll(block.getValues(), block.getWeight());
allValues.addAll(block.getValues());
weight = LongMath.saturatedAdd(weight, block.getWeight());
}
if (newWeight < 0) {
if (newValues.size() == 1) {
// Optimize weighing of the common value state as single single-element bag state.
newWeight = Caches.weigh(newValues.get(0));
} else {
newWeight = Caches.weigh(newValues);
newWeight = 0;
for (T value : newValues) {
newWeight = LongMath.saturatedAdd(newWeight, Caches.weigh(value));
}
}
allValues.addAll(newValues, newWeight);
allValues.addAll(newValues);
weight = LongMath.saturatedAdd(weight, newWeight);

cache.put(IterableCacheKey.INSTANCE, new MutatedBlocks<>(Block.mutatedBlock(allValues)));
cache.put(IterableCacheKey.INSTANCE, new MutatedBlocks<>(Block.fromValues(allValues.build(), weight, null)));
}

class CachingStateIterator implements PrefetchableIterator<T> {
Expand Down Expand Up @@ -580,8 +602,7 @@ public boolean hasNext() {
return false;
}
// Release the block while we are loading the next one.
currentBlock =
Block.fromValues(WeightedList.of(Collections.emptyList(), 0L), ByteString.EMPTY);
currentBlock = Block.emptyBlock();

@Nullable Blocks<T> existing = cache.peek(IterableCacheKey.INSTANCE);
boolean isFirstBlock = ByteString.EMPTY.equals(nextToken);
Expand Down
Loading