📣 [ANNOUNCE] Apache Pulsar 3.0.14, 3.3.9, 4.0.7 and 4.1.1 released 📣 For Pulsar release details and downloads, visit: https://pulsar.apache.org/download Release Notes are at: • 3.0.14: https://pulsar.apache.org/release-notes/versioned/pulsar-3.0.14/ (previous LTS release, support until May 2026) • 3.3.9: https://pulsar.apache.org/release-notes/versioned/pulsar-3.3.9/ (support has already ended in December 2024) • 4.0.7: https://pulsar.apache.org/release-notes/versioned/pulsar-4.0.7/ (Current LTS release) • 4.1.1: https://pulsar.apache.org/release-notes/versioned/pulsar-4.1.1/ (Latest release) Please check the release notes for more details.

Hi, Seems to me an answer to my question could be quite useful to a lot of people new to Pulsar that try to design around it with constraint of effectively one delivery semantics. Is there anything I can do to get some attention to it from Pulsar community?

Hi, I'm running a Pulsar 4.0.2 Cluster (3 broker, 3 bookies, 3 zookeeper) with partitioned topics and I have two problems: 1. The filesystem usage on the bookies doesn't seem to go down (bk1: 100GB, bk2: 400GB, bk3: 100G). I already set a retention policy on my main namespace (2weeks, 10GB) and the metriks in Grafana report the correct topic sizes (100GB storage size and ~30GB backlog size). I get the usage on bk1 and bk3, but not the 400GB on bk2... 2. The bookie service on bk2 stops frequently with an error "io.netty.util.internal.OutOfDirectMemoryError: failed to allocate 4194304 byte(s) of direct memory (used: 2147483648, max: 2147483648)". I can't find the setting where I can control the limit for this memory setting. I already increased the jvm allocations in the pulsar_env.sh those don't seem to correlate.. Thanks!

We've just released Apache Pulsar Helm Chart 4.3.0 🎉 The official source release, as well as the binary Helm Chart release, are available at https://www.apache.org/dyn/closer.lua/pulsar/helm-chart/4.3.0/?action=download The helm chart index at https://pulsar.apache.org/charts/ has been updated and the release is also available directly via helm. Release Notes: https://github.com/apache/pulsar-helm-chart/releases/tag/pulsar-4.3.0 Docs: https://github.com/apache/pulsar-helm-chart#readme and https://pulsar.apache.org/docs/helm-overview ArtifactHub: https://artifacthub.io/packages/helm/apache/pulsar/4.3.0 Thanks to all the contributors who made this possible.

Hello, I want to use pulsar with .Net but the librsry dotpulsar is too basic without many features, so I saw this client matrix https://pulsar.apache.org/client-feature-matrix/#consumer Where there is a column called .Net (C#,F#,VB), is this other library?

Hi Team, We are currently operating a clustered environment consisting of two instances, running Apache Pulsar version 4.1.1 . During load testing, with "brokerDeduplicationEnabled= true", we have encountered issues related to message loss. For your reference and to support further analysis, I have attached the broker configuration file. And the MessageId corresponding to an unpublished message is. { "partition": -1, "ledgerId": -9223372036854800000.0, "batchIndex": -1, "entryId": -9223372036854800000.0 } DotPulsar version 4.3.2 is being used as the client library. We would appreciate your assistance in investigating this issue and welcome any insights or recommendations you may have.

Subject: Bookie crashes with -25 error when enabling StreamStorageLifecycleComponent (Pulsar 4.1.1) Hi everyone 👋 — I’m setting up a small Pulsar 4.1.1 cluster and running into an issue when enabling stream storage. Cluster Setup I have 3 VMs: Host CPUs RAM Storage Roles 10.0.1.74 8 16GB 500GB SSD ZooKeeper + Bookie + Broker 10.0.1.75 8 16GB 400GB SSD ZooKeeper + Bookie + Broker 10.0.1.91 12 64GB 100GB SSD ZooKeeper Cluster Init Command bash bin/pulsar initialize-cluster-metadata \ --cluster dev-cluster-1 \ --metadata-store zk10.0.1.742181,10.0.1.752181,10.0.1.912181 \ --configuration-metadata-store zk10.0.1.742181,10.0.1.752181,10.0.1.912181 \ --web-service-url http://10.0.1.74:8080,10.0.1.75:8080 \ --web-service-url-tls https://10.0.1.74:8443,10.0.1.75:8443 \ --broker-service-url pulsar://10.0.1.74:6650,10.0.1.75:6650 \ --broker-service-url-tls pulsar+ssl://10.0.1.74:6651,10.0.1.75:6651 Bookie Config (relevant parts) properties storageserver.grpc.port=4181 dlog.bkcEnsembleSize=2 dlog.bkcWriteQuorumSize=2 dlog.bkcAckQuorumSize=1 storage.range.store.dirs=data/bookkeeper/ranges storage.serve.readonly.tables=false storage.cluster.controller.schedule.interval.ms=30000 Issue When I run Pulsar in stateless mode, ZooKeeper, BookKeeper, and Brokers all start fine. But when I enable: properties extraServerComponents=org.apache.bookkeeper.stream.server.StreamStorageLifecycleComponent both Bookies crash shortly after startup with a BKTransmitException and error -25. Printed using ChatGPT to PDF, powered by PDFCrowd HTML to PDF API. 8/9 Excerpt from logs kotlin Caused by: org.apache.distributedlog.exceptions.BKTransmitException: Failed to open ledger handle for log segment ... : -25 What I’ve tried Verified ZooKeeper quorum and BookKeeper ledger directories Cleaned /data/bookkeeper and restarted the cluster Ensured the ensemble/write/ack quorum configs match cluster size Question Has anyone successfully enabled the stream storage component (StreamStorageLifecycleComponent) on Pulsar 4.1.1? What does the -25 (BKTransmitException) usually indicate in this context — ZK metadata corruption, missing ledger, or a config mismatch? Any guidance or example configurations for Pulsar 4.x stream storage clusters would be greatly appreciated

Hi Team 👋 I'm investigating an issue related to the Pulsar broker configuration parameter

delayedDeliveryTrackerFactoryClassName

. We initially used

InMemoryDelayedDeliveryTracker

, (because we where using version 2.7 of pulsar) which caused acknowledged delayed messages to be reprocessed after a broker restart likely due to its state stored only in memory. Given our high message volume (millions), this behavior is problematic. A screenshot is available showing the lag escalation following a broker restart. We're generating delayed messages out of sequence, resulting in gaps within the acknowledged message stream. This causes non-contiguous ranges of messages to be marked as deleted or eligible for deletion. In our screenshot, the value of

nonContiguousDeletedMessagesRanges

is 16833. To mitigate this following the upgrade of pulsar to the version 4.0.4, we updated the broker config to use

org.apache.pulsar.broker.delayed.BucketDelayedDeliveryTrackerFactory

, which should persist delayed delivery metadata to disk via BookKeeper ledger buckets. However, after switching to the bucket-based tracker, we're still seeing the same behavior post-restart. A few observations and questions: • I checked the

pulsar_delayed_message_index_loaded

metric and noticed that messages are still being loaded into memory, while

pulsar_delayed_message_index_bucket_total

remains at zero. Is this expected? Shouldn’t the bucket tracker be persisting and loading from disk? • Are there additional broker settings required to fully enable bucket-based delayed delivery tracking? For example: ◦ Do we need to explicitly configure

delayedDeliveryTrackerBucketSize

or

delayedDeliveryMaxNumBuckets

? ◦ Is there any dependency on topic-level settings or namespace policies that could override the broker-level tracker configuration? ◦ Could other settings interfere with delayed message persistence? Any insights or guidance would be greatly appreciated. Thanks for your help!

Hi team: I DO REALLY NEED THE HELP RIGHT NOW. One of my bookie node in the production cluster are stuck in the CrashLoopBackOff status; after checking the logs, I find out that it is because the node cannot successfully access the lock from the metadata server (which we use Oxia in our cluster). I have tried to restart the Oxia cluster, since I saw some error messages saying that the oxia cannot append the WAL to the stream (I were facing the similar situation last month, and the restarting Oxia trick did work for me). Unfortunately, the bookie node still cannot get it's own lock after restarting the Oxia. I REALLY NEED SOMEONE THAT CAN HELP ME OUT WITH THE ISSUE 😢

we seeing Oxia as a metadata storage system crashing repeatedly for us after 20 minutes of use with WAL corruption as described here https://github.com/oxia-db/oxia/issues/772 did anyone experienced something similar and can share workarounds?

Hi all... I'm debugging an issue where we're using Pulsar with non-persistent topics, and in this case, we have only 1 consumer. The data rate is low -- ~5000 msgs/sec, 1kb each -- but we see some small amount of drops. Normally, we have much larger scale and we can successfully run with 50 consumers at 3 million msgs/sec with 0 drops. So it's odd we have drops here where CPU usage on every component is quite low. The Pulsar consumer receive queue is set to 50k and never gets low. I've also taken our software out of it and replaced our consumers with the sample Java consumer code from the docs. There, we just throw away the message (no

println()

or other work per message). Again, CPU usage is under 10% for all components, but I see the same small drops. I started debugging and found Pulsar is dropping because the Netty connection's

.isWritable()

returns false and this causes Pulsar to immediately drop. This "Returns

true

if and only if the I/O thread will perform the requested write operation immediately", meaning there is room available in Netty's ChannelOutboundBuffer. I found that if I increase the Netty low/highWaterMarks, the drops go away, but it's not possible without a code change to Pulsar broker. I'm looking for any suggestions on different configurations I can try. Thanks!!

We are using Apache Spark for batch processing and are now planning to extend the same for Stream Processing. I was checking the stream-native pulsar connector and was wondering does it supports Continuous Trigger or RealTime trigger like Databricks? The idea is to have sub-milliseconds end-to-end latency. Is this at all possible with Pulsar <> Spark?

📣 Dekaf UI is now open-source software licensed under Apache 2.0: https://github.com/visortelle/dekaf Please try, rise bugs, feature requests, and ask questions on GitHub. Thank you!

Hi all, is there a good guide for migrating from zookeeper to oxia? My searches are coming up empty. Thanks 😄

Unfortunately, there isn’t really an easy way to do that. The main issue is that the data is stored in very different formats, so it can’t just be copied.

Hi all, I have a question about this issue: https://github.com/apache/pulsar-client-go/issues/1297. We don’t specify consumers' name, and I understand that Pulsar will create a unique name in that case. However, if the consumer name is unique, shouldn’t the producer name (

..<subscription>-<consumerName>-DLQ

) be as well, since it uses the consumer name in the producer’s name? Will consumer stop consuming message if this happen? We are using Pulsar client 4.0.0 where producer name constructed as:

.producerName(String.format("%s-%s-%s-DLQ", this.topicName, this.subscription, this.consumerName))

Hi everyone We’re using Pulsar with strict schema governance - each namespace has

schemaValidationEnforced=true

and

isAllowAutoUpdateSchema=false

(only under an approved process), so only admins can push schemas. Here’s the issue: when a consumer is configured with a

DeadLetterPolicy

and a message fails too many times (or is negatively acknowledged repeatedly), the client will publish the message to a dead-letter topic (default name

<topic>-<subscription>-DLQ

) after the redelivery threshold. That topic doesn’t necessarily exist ahead of time (unless created before), so when it’s first used it may trigger topic creation and/or schema registration. Because our namespace forbids auto schema updates and enforces schemas, this can fail - the consumer isn’t authorized to register the schema for the DLQ topic. To work around this, we’re creating a separate namespace (e.g.,

<namespace>-dlq

) where: •

isAllowAutoUpdateSchema=true

•

schemaValidationEnforced=false

• so consumers can safely publish DLQ messages without schema conflicts. Is this the recommended approach? Is there a cleaner way to allow DLQ schema creation while keeping production namespaces locked down? Any official guidance or community best practices would be really appreciated 🙏 Thanks!

hello everybody, I have a reproducible test case that demonstrate that pulsar 2-way geo replication doesn't support exclusive access producers. If this is a limitation made by design, I am not sure what benefit that could bring. Otherwise, if it's not a limitation made by design, I believe that it should be resolved to strengthen and improve the pulsar geo replication feature. I have opened this issue 24914. Will appreciate if someone can take a look and suggest whether it makes sense or not.

Hi Folks, I was exploring Apache Pulsar functions. From the documentation, we seem to use Apache Bookkeeper as the state storage interface. Couple of questions on the state storage for pulsar functions: 1\ Do we have any upper limit on the storage allocated for the pulsar function state storage? 2\ Do we have a tiered storage paradigm even for the pulsar function state storage similar to the event stream storage? TIA.

I’m facing a problem where the consumer internal DLQ producer can’t connect due to a conflict with another producer with the same name. This issue was fixed in version 4.1.0, but it requires Java 17, which is not feasible for us at the moment (still with java8 ) I want to implement a short-term workaround to detect this issue and recreate the consumer with a different name, which, in theory, should resolve the conflict. The pulsar client implementation, however, seems to hide the entire DLQ handling, with exceptions not thrown or propagated back to external code. Is there a way to archive what I need here?

Hey! I'm evaluating migration options for moving our Pulsar stacks from EC2 to Kubernetes environments, where the requirement is to minimize the service downtime. So far so good I learned a lot about the geo-replication, which could be used by me, but I'm wondering what the story is behind the PIP-188 https://github.com/apache/pulsar/issues/16551 . AFAIk the work has been delivered, but I can't find instructions on how to leverage and try this solution. The list of features is impressive

Publish ordering guarantee
Consumer ordering guarantee
Incoming replicator ordering guarantee
Outgoing replicator ordering guarantee with the topic unavailability tradeoff
Auto resource creation (tenant, namespace, partitioned-topic, subscriptions) in a green cluster
Auto topic deletion after migration successfully completed for a topic
Enable migration at cluster level or per namespace level
Stats to show topic's migration state

But the thing is that due to missing configuration steps, it's hard to test this feature. Can someone explain how to start with that?

<URGENT> Hi, there are many .log files under the /data/bookie1/ledgers/current directory, which occupy a large amount of space. How can I clean them up? For temporary fix can i manually delete these log files ?

Pulsar Flink Connector side we don't have any support from Pulsar side, currently?

Hi Team ,On pulsar bookkeeper server under /data/bookkeeper/ledgers/current there are old .log files which are older like 2 years more , we set retention in broker for acknowlege messages to 60 minutes . But still the old log files are not getting delete , ledger is the most consuming one which is filling disk space Checked https://apache-pulsar.slack.com/archives/C5Z4T36F7/p176278302931373

📣 [ANNOUNCE] Apache Pulsar 3.0.15, 4.0.8 and 4.1.2 released 📣 For Pulsar release details and downloads, visit: https://pulsar.apache.org/download Release Notes are at: • 3.0.15: https://pulsar.apache.org/release-notes/versioned/pulsar-3.0.15/ (previous LTS release, support until May 2026) • 4.0.8: https://pulsar.apache.org/release-notes/versioned/pulsar-4.0.8/ (Current LTS release) • 4.1.2: https://pulsar.apache.org/release-notes/versioned/pulsar-4.1.2/ (Latest release) Please check the release notes for more details.

Hi everyone, has anyone experience

504 Gateway Timeout

from pulsar clients in a production cluster ? We are currently experiencing timeout of proxies from time to time on multiple clusters with a HTTP

504

, exception message is

SSL BAD PACKET LENGTH

. It looks like an issue between proxy - broker connection pool, but cannot yet prove it. We're running

4.1.0

We have to reboot proxies to fix the issue for now

What's the technical reason between having journal/ledger on same nvme versus having two separate drives, one for journal and one for ledgers?

There are several reasons why you should have the journal and ledger disks on separate physical volumes, including performance. But the primary reason is that they serve two different purposes. The journal disk is used for short-term storage of the messages before they are indexed and written to the ledger disk. The journal disk provides data durability guarantees in the event of a failure, the bookie can recover and load the messages from the journal disk. However, if the journal disk fails, Pulsar will continue to operate. So separating them eliminates a single point of failure from the storage layer as well.

Hi all 👋 I have a question about per-key scheduling behavior in Pulsar. I need strict ordering and exclusivity per

sensor_id

, but I don’t want long-lived key to consumer stickiness. Instead, I’m trying to achieve this logic:

If no consumer is currently processing

sensor_id = X

, then the next message for that sensor should be assigned to the next available consumer (round-robin or least-loaded).

All while preserving ordering and ensuring no two consumers ever process the same key concurrently.

KeyShared

ensures ordering and exclusivity, but it uses stable key-range hashing, so a key stays with one consumer until that consumer dies. Is there any Pulsar pattern, config, or upcoming feature that supports dynamic per-message key assignment instead of sticky key-range ownership? Or is this fundamentally outside Pulsar’s delivery semantics? Thanks! 🙏

We already use a shared subscription with

KeyShare

option, since we do want messages to be processed in order per Key (this is something our design requires)