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HDDS-8913. ContainerManagerImpl: reduce processing while locked #4967

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Merged
adoroszlai merged 2 commits into from
Jun 27, 2023
Merged

HDDS-8913. ContainerManagerImpl: reduce processing while locked #4967

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HDDS-8913. ContainerManagerImpl: reduce processing while locked
adoroszlai Jun 23, 2023
19226d3
implement findTopN using PriorityQueue
adoroszlai Jun 27, 2023
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2 changes: 2 additions & 0 deletions hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/scm/container/ContainerID.java
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,8 @@ public final class ContainerID implements Comparable<ContainerID> {
LongCodec.get(), ContainerID::valueOf, c -> c.id,
DelegatedCodec.CopyType.SHALLOW);

public static final ContainerID MIN = ContainerID.valueOf(0);

public static Codec<ContainerID> getCodec() {
return CODEC;
}
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96 changes: 51 additions & 45 deletions ...s/server-scm/src/main/java/org/apache/hadoop/hdds/scm/container/ContainerManagerImpl.java
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Expand Up @@ -19,19 +19,18 @@

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NavigableSet;
import java.util.Objects;
import java.util.Optional;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.Collectors;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
Expand Down Expand Up @@ -144,55 +143,23 @@ public ContainerInfo getContainer(final ContainerID id)
public List<ContainerInfo> getContainers(final ContainerID startID,
final int count) {
scmContainerManagerMetrics.incNumListContainersOps();
final List<ContainerID> containersIds =
new ArrayList<>(containerStateManager.getContainerIDs());
Collections.sort(containersIds);
List<ContainerInfo> containers;
lock.lock();
try {
containers = containersIds.stream()
.filter(id -> id.compareTo(startID) >= 0).limit(count)
.map(containerStateManager::getContainer)
.collect(Collectors.toList());
} finally {
lock.unlock();
}
return containers;
return toContainers(filterSortAndLimit(startID, count,
containerStateManager.getContainerIDs()));
}

@Override
public List<ContainerInfo> getContainers(final LifeCycleState state) {
List<ContainerInfo> containers;
lock.lock();
try {
containers = containerStateManager.getContainerIDs(state).stream()
.map(containerStateManager::getContainer)
.filter(Objects::nonNull).collect(Collectors.toList());
} finally {
lock.unlock();
}
return containers;
scmContainerManagerMetrics.incNumListContainersOps();
return toContainers(containerStateManager.getContainerIDs(state));
}

@Override
public List<ContainerInfo> getContainers(final ContainerID startID,
final int count,
final LifeCycleState state) {
scmContainerManagerMetrics.incNumListContainersOps();
final List<ContainerID> containersIds =
new ArrayList<>(containerStateManager.getContainerIDs(state));
Collections.sort(containersIds);
List<ContainerInfo> containers;
lock.lock();
try {
containers = containersIds.stream()
.filter(id -> id.compareTo(startID) >= 0).limit(count)
.map(containerStateManager::getContainer)
.collect(Collectors.toList());
} finally {
lock.unlock();
}
return containers;
return toContainers(filterSortAndLimit(startID, count,
containerStateManager.getContainerIDs(state)));
}

@Override
Expand Down Expand Up @@ -431,18 +398,24 @@ public void notifyContainerReportProcessing(final boolean isFullReport,
public void deleteContainer(final ContainerID cid)
throws IOException, TimeoutException {
HddsProtos.ContainerID protoId = cid.getProtobuf();

final boolean found;
lock.lock();
try {
if (containerExist(cid)) {
found = containerExist(cid);
if (found) {
containerStateManager.removeContainer(protoId);
scmContainerManagerMetrics.incNumSuccessfulDeleteContainers();
} else {
scmContainerManagerMetrics.incNumFailureDeleteContainers();
throwContainerNotFoundException(cid);
}
} finally {
lock.unlock();
}

if (found) {
scmContainerManagerMetrics.incNumSuccessfulDeleteContainers();
} else {
scmContainerManagerMetrics.incNumFailureDeleteContainers();
throwContainerNotFoundException(cid);
}
}

@Override
Expand Down Expand Up @@ -471,4 +444,37 @@ public ContainerStateManager getContainerStateManager() {
public SCMHAManager getSCMHAManager() {
return haManager;
}

private static List<ContainerID> filterSortAndLimit(
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@sodonnel sodonnel Jun 27, 2023 •
edited
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I think this could be made more efficient. The current algorithm takes the set, forms a new list of all elements. Then filters, sorted and returns the range.

Using an adaption of the priorityQueue technique here - https://www.baeldung.com/java-array-top-elements

We could avoid the copy from set to list, and the potentially large sort.

for (contaienrID cid : set) {
    if (id > startID)
        maxHeap.add(number);

        if (maxHeap.size() > count) {
            maxHeap.poll();
        }
    }
});
return new ArrayList<>(maxHeap);
// Might need reversed, I am not sure

I think this would be more memory efficient on large container sets, and should perform better than the full sort

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@adoroszlai adoroszlai Jun 27, 2023 •
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Thanks for the suggestion, I'll update the patch with it.

FYI there is a bug in that solution due to PriorityQueue#iterator():

The iterator does not return the elements in any particular order.

so new ArrayList<>(maxHeap) randomizes the result.

It seems to work for (small?) Integers, but not for any random Comparable.

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@sodonnel sodonnel Jun 27, 2023

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I wonder how many people have not noticed that issue, and just implemented the linked solution as is!

ContainerID startID, int count, Set<ContainerID> set) {

List<ContainerID> ids = new ArrayList<>(set);

// only filter if startID is not the minimum one
if (!startID.equals(ContainerID.MIN)) {
ids.removeIf(id -> id.compareTo(startID) < 0);
}

// sort after removing unnecessary items
Collections.sort(ids);

// limit
return ids.subList(0, Math.min(ids.size(), count));
}

/**
* Returns a list of all containers identified by {@code ids}.
*/
private List<ContainerInfo> toContainers(Collection<ContainerID> ids) {
List<ContainerInfo> containers = new ArrayList<>(ids.size());

for (ContainerID id : ids) {
ContainerInfo container = containerStateManager.getContainer(id);
if (container != null) {
containers.add(container);
}
}

return containers;
}
}
3 changes: 2 additions & 1 deletion ...ver-scm/src/main/java/org/apache/hadoop/hdds/scm/container/states/ContainerAttribute.java
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Expand Up @@ -18,6 +18,7 @@
package org.apache.hadoop.hdds.scm.container.states;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSortedSet;
import org.apache.hadoop.hdds.scm.container.ContainerID;
import org.apache.hadoop.hdds.scm.exceptions.SCMException;
import org.slf4j.Logger;
Expand Down Expand Up @@ -189,7 +190,7 @@ public NavigableSet<ContainerID> getCollection(T key) {
Preconditions.checkNotNull(key);

if (this.attributeMap.containsKey(key)) {
return Collections.unmodifiableNavigableSet(this.attributeMap.get(key));
return ImmutableSortedSet.copyOf(this.attributeMap.get(key));
}
if (LOG.isDebugEnabled()) {
LOG.debug("No such Key. Key {}", key);
Expand Down
3 changes: 2 additions & 1 deletion ...rver-scm/src/main/java/org/apache/hadoop/hdds/scm/container/states/ContainerStateMap.java
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Expand Up @@ -28,6 +28,7 @@

import com.google.common.base.Preconditions;

import com.google.common.collect.ImmutableSet;
import org.apache.hadoop.hdds.client.ReplicationConfig;
import org.apache.hadoop.hdds.scm.container.ContainerID;
import org.apache.hadoop.hdds.scm.container.ContainerReplica;
Expand Down Expand Up @@ -295,7 +296,7 @@ public void updateState(ContainerID containerID, LifeCycleState currentState,
}

public Set<ContainerID> getAllContainerIDs() {
return Collections.unmodifiableSet(containerMap.keySet());
return ImmutableSet.copyOf(containerMap.keySet());
}

/**
Expand Down