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Databases · head to head

Apache Pulsar vs DuckDB

Apache Pulsar logo

Apache Pulsar

Databases

Cloud-native messaging and streaming with separated storage

From
Free
Rated
-
Full reviewWebsite
DuckDB logo

DuckDB

Databases

Fast in-process analytical database

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Apache Pulsar more components than Kafka: brokers, BookKeeper and ZooKeeper each need operating; DuckDB client-server setup remains in beta and not recommended for production distributed scenarios
  • They diverge on capability: Apache Pulsar covers Separated storage, DuckDB covers In-process Execution.

Where they differ

Only the attributes on which Apache Pulsar and DuckDB actually diverge.

Attributes where Apache Pulsar and DuckDB differ
AttributeApache PulsarDuckDB
Pricing modelOpen source, no licence feeopen-source
PlatformsLinux, Docker, Kubernetes, Self-hostedLinux, macOS, Windows, WebAssembly
FoundedUnknown2019

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Databases).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Apache Pulsar

  • Separated storage
  • Queuing and streaming
  • Built-in multi-tenancy
  • Geo-replication

Only in DuckDB

  • In-process Execution
  • Columnar Storage
  • Vectorized Execution
  • Rich SQL Support
  • Parquet Support
  • CSV/JSON Import
  • Zero Dependencies
  • Python

What people use each for

The jobs each tool is most often brought in to do.

Apache Pulsar

  • Platforms needing both work queues and replayable streams without running two systemsnot DuckDB
  • Multi-tenant messaging where isolation between teams is a requirementnot DuckDB
  • Deployments where storage and traffic grow at genuinely different ratesnot DuckDB

DuckDB

  • Analytics and data warehousingnot Apache Pulsar
  • OLAP queries and data explorationnot Apache Pulsar
  • Data science and machine learning workflowsnot Apache Pulsar
  • Multi-format data ingestion and processingnot Apache Pulsar

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Apache Pulsar

  • More components than Kafka: brokers, BookKeeper and ZooKeeper each need operating
  • Correspondingly harder to run well, and the expertise is rarer than Kafka expertise
  • A much smaller ecosystem of connectors, tooling and hiring pool than Kafka
  • The architectural advantages only pay off at a scale most deployments never reach

DuckDB

  • Client-server setup remains in beta and not recommended for production distributed scenarios

Pricing, plan by plan

Apache Pulsar

Free
  • Apache PulsarFree
    • Full functionality
    • No usage limits
    • Community support

DuckDB

Free

No published plan breakdown. See the DuckDB review.

Which should you pick?

Choose Apache Pulsar if

  • You need separated storage.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Self-hosted.
  • You also want queuing and streaming.
Apache Pulsar review

Choose DuckDB if

  • You need in-process execution.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, WebAssembly.
  • You also want columnar storage.
DuckDB review

Questions people ask

Is Apache Pulsar or DuckDB better?
Neither clearly leads. Apache Pulsar starts at Free and DuckDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Pulsar or DuckDB?
Apache Pulsar starts at Free and DuckDB at Free.
Does Apache Pulsar or DuckDB run on more platforms?
Apache Pulsar runs on Linux, Docker, Kubernetes, Self-hosted. DuckDB runs on Linux, macOS, Windows, WebAssembly.
Can I use Apache Pulsar for free?
Both have a free tier, so you can try either at no cost before committing.
What is Apache Pulsar best used for?
Apache Pulsar is most often used for platforms needing both work queues and replayable streams without running two systems, multi-tenant messaging where isolation between teams is a requirement, deployments where storage and traffic grow at genuinely different rates. Of those, platforms needing both work queues and replayable streams without running two systems and multi-tenant messaging where isolation between teams is a requirement are not what DuckDB is typically brought in for.
What can Apache Pulsar do that DuckDB cannot?
Apache Pulsar covers Separated storage, Queuing and streaming, Built-in multi-tenancy, Geo-replication. DuckDB covers In-process Execution, Columnar Storage, Vectorized Execution, Rich SQL Support.

Answered from the vendors’ own pages

Apache Pulsar: Is Apache Pulsar free?

Yes, open source under the Apache Software Foundation.

DuckDB: Is DuckDB free to use?

Yes, DuckDB is completely free. There are no subscription tiers, user limits, or paid plans. The software has zero licensing costs.

Source
Apache Pulsar: Pulsar or Kafka?

Pulsar separates storage from compute and covers queuing and streaming in one system. Kafka has a far larger ecosystem and hiring pool. Most teams should have a specific reason before choosing Pulsar.

DuckDB: What license is DuckDB distributed under?

DuckDB is open source under the MIT License, governed by the independent DuckDB Foundation. The MIT License permits commercial use, modification, and distribution with minimal restrictions.

Source
Apache Pulsar: Why does separated storage matter?

Brokers hold no data, so adding or replacing one requires no rebalancing, and storage can grow without adding serving capacity.

DuckDB: Can I use DuckDB in commercial applications?

Yes, the MIT License allows commercial use without restrictions or requirements to publish proprietary code. You can deploy DuckDB anywhere from edge devices to high-core servers.

Source
DuckDB: Are there any limitations on how many instances I can run?

No, there are no user limits, usage limits, or instance restrictions. You have unlimited access to all DuckDB features.

Source
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