[fix][broker][branch-4.0] Revert "[improve][broker] Reduce memory occupation of the delayed message queue (#23611)"

[codelipenghui]

Motivation

• Revert: [improve][broker] Reduce memory occupation of the delayed message queue #23611
• Mailing list discussion: https://lists.apache.org/thread/3dc1c3n7d0tmwm8974qh9w771jzgy6f6

Reason for Revert:

This PR has introduced a significant performance regression in the Pulsar broker.
The attached flame graph visually demonstrates increased CPU utilization and time
spent in the code paths related to DelayedDeliveryTracker and stream operations.

While the intention was to optimize memory usage, the current implementation
appears to have an adverse effect on CPU performance, leading to overall degraded
broker throughput and increased latency.

Impact:

This regression is impacting the stability and performance of our Pulsar clusters,
especially when you have large-scale delayed messages. Reverting the change will
allow us to restore the previous performance characteristics while we investigate
a more robust and performant solution for DelayedDeliveryTracker memory optimization.

Root Cause:

https://github.com/apache/pulsar/pull/23611/files#diff-f159b4e262ff6213bba19d20e6dc01d07ea8c19f4675524e4ceb1470f456e8fcR229-R231
Here is the change that caused this issue. Each message added to the
DelayedMessageTracker will call getNumberOfDelayedMessages() method
which will iterate the map defined in InMemoryDelayedDeliveryTracker

protected final Long2ObjectSortedMap<Long2ObjectSortedMap<Roaring64Bitmap>>
delayedMessageMap = new Long2ObjectAVLTreeMap<>();

More contexts:

Flamegraph:

Jstack:

"broker-topic-workers-OrderedExecutor-1-0" #51 [95] prio=5 os_prio=0 cpu=1678706.57ms elapsed=15712.43s tid=0x00007fa0da32b820 nid=95 runnable  [0x00007fa0d6c00000]
   java.lang.Thread.State: RUNNABLE
        at java.util.stream.AbstractPipeline.wrapSink([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto([email protected]/Unknown Source)
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.evaluate([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.reduce([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.sum([email protected]/Unknown Source)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker.lambda$getNumberOfDelayedMessages$3(InMemoryDelayedDeliveryTracker.java:231)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker$$Lambda/0x0000000100e73078.applyAsLong(Unknown Source)
        at java.util.stream.ReferencePipeline$5$1.accept([email protected]/Unknown Source)
        at java.util.Iterator.forEachRemaining([email protected]/Unknown Source)
        at it.unimi.dsi.fastutil.objects.ObjectSpliterators$SpliteratorFromIterator.forEachRemaining(ObjectSpliterators.java:1158)
        at java.util.stream.AbstractPipeline.copyInto([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto([email protected]/Unknown Source)
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.evaluate([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.reduce([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.sum([email protected]/Unknown Source)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker.getNumberOfDelayedMessages(InMemoryDelayedDeliveryTracker.java:231)
        at org.apache.pulsar.broker.delayed.AbstractDelayedDeliveryTracker.updateTimer(AbstractDelayedDeliveryTracker.java:91)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker.addMessage(InMemoryDelayedDeliveryTracker.java:128)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.trackDelayedDelivery(PersistentDispatcherMultipleConsumers.java:1314)
        - locked <0x00000000c21d88b8> (a org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers)
        at org.apache.pulsar.broker.service.AbstractBaseDispatcher.filterEntriesForConsumer(AbstractBaseDispatcher.java:228)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.trySendMessagesToConsumers(PersistentDispatcherMultipleConsumers.java:864)
        - locked <0x00000000c21d88b8> (a org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.sendMessagesToConsumers(PersistentDispatcherMultipleConsumers.java:769)
        - eliminated <0x00000000c21d88b8> (a org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.handleSendingMessagesAndReadingMore(PersistentDispatcherMultipleConsumers.java:729)
        - locked <0x00000000c21d88b8> (a org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.lambda$readEntriesComplete$9(PersistentDispatcherMultipleConsumers.java:719)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers$$Lambda/0x0000000100c0f440.run(Unknown Source)
        at org.apache.bookkeeper.common.util.SingleThreadExecutor.safeRunTask(SingleThreadExecutor.java:128)
        at org.apache.bookkeeper.common.util.SingleThreadExecutor.run(SingleThreadExecutor.java:99)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.runWith([email protected]/Unknown Source)
        at java.lang.Thread.run([email protected]/Unknown Source)

"broker-topic-workers-OrderedExecutor-2-0" #52 [96] prio=5 os_prio=0 cpu=1797445.47ms elapsed=15712.43s tid=0x00007fa0d9419fc0 nid=96 runnable  [0x00007fa0d6aff000]
   java.lang.Thread.State: RUNNABLE
        at java.util.stream.AbstractPipeline.copyInto([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto([email protected]/Unknown Source)
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.evaluate([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.reduce([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.sum([email protected]/Unknown Source)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker.lambda$getNumberOfDelayedMessages$3(InMemoryDelayedDeliveryTracker.java:231)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker$$Lambda/0x0000000100e73078.applyAsLong(Unknown Source)
        at java.util.stream.ReferencePipeline$5$1.accept([email protected]/Unknown Source)
        at java.util.Iterator.forEachRemaining([email protected]/Unknown Source)
        at it.unimi.dsi.fastutil.objects.ObjectSpliterators$SpliteratorFromIterator.forEachRemaining(ObjectSpliterators.java:1158)
        at java.util.stream.AbstractPipeline.copyInto([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto([email protected]/Unknown Source)
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential([email protected]/Unknown Source)
        at java.util.stream.AbstractPipeline.evaluate([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.reduce([email protected]/Unknown Source)
        at java.util.stream.LongPipeline.sum([email protected]/Unknown Source)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker.getNumberOfDelayedMessages(InMemoryDelayedDeliveryTracker.java:231)
        at org.apache.pulsar.broker.delayed.AbstractDelayedDeliveryTracker.updateTimer(AbstractDelayedDeliveryTracker.java:91)
        at org.apache.pulsar.broker.delayed.InMemoryDelayedDeliveryTracker.getScheduledMessages(InMemoryDelayedDeliveryTracker.java:217)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.getMessagesToReplayNow(PersistentDispatcherMultipleConsumers.java:1327)
        - locked <0x00000000b8cd7968> (a org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.readMoreEntries(PersistentDispatcherMultipleConsumers.java:386)
        - locked <0x00000000b8cd7968> (a org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.handleSendingMessagesAndReadingMore(PersistentDispatcherMultipleConsumers.java:743)
        - locked <0x00000000b8cd7968> (a org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers.lambda$readEntriesComplete$9(PersistentDispatcherMultipleConsumers.java:719)
        at org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleConsumers$$Lambda/0x0000000100c0f440.run(Unknown Source)
        at org.apache.bookkeeper.common.util.SingleThreadExecutor.safeRunTask(SingleThreadExecutor.java:128)
        at org.apache.bookkeeper.common.util.SingleThreadExecutor.run(SingleThreadExecutor.java:99)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.runWith([email protected]/Unknown Source)
        at java.lang.Thread.run([email protected]/Unknown Source)

Modifications

Revert PR #23611 and the related PR #24035

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[codelipenghui]

/pulsarbot run-failure-checks

[BewareMyPower]

The attached flame graph visually demonstrates increased CPU utilization and time
spent in the code paths related to DelayedDeliveryTracker

Where is the flame graph?

[codelipenghui]

@BewareMyPower Uploaded. I have been attached to the mailing list before. Forgot to add them here.