KDB+ has long been the gold standard for financial time-series data. Its column-oriented architecture and the q programming language make it exceptionally fast for tick data analysis. So why are we increasingly recommending ClickHouse for new projects—and even migrating existing KDB+ deployments?
The Case for KDB+
Let's be clear: KDB+ is a remarkable piece of technology. Its strengths include:
- •Raw Query Speed: For certain query patterns, KDB+ remains unmatched
- •Memory Efficiency: Compressed in-memory storage with excellent cache utilization
- •Integrated Language: The q language allows complex analytics in concise expressions
- •Industry Pedigree: Battle-tested at the world's largest trading firms
If money were no object and you had access to experienced q developers, KDB+ would still be a strong choice.
The Reality Check
However, we've seen recurring challenges with KDB+ in practice:
Licensing Costs
KDB+ licensing is expensive—often $50,000+ per core per year for production use. For a firm running a 16-core production server with a hot standby and development environment, you're looking at $2M+ annually just for database licensing.
Talent Scarcity
The q programming language is notoriously difficult to learn. Experienced q developers are rare and command premium salaries. When your single q developer leaves, you have a serious business continuity problem.
Operational Complexity
KDB+ lacks many features that modern databases take for granted: no built-in replication, limited tooling for monitoring and administration, and challenging integration with modern DevOps practices.
Enter ClickHouse
ClickHouse, developed by Yandex and now maintained by ClickHouse Inc., is an open-source column-oriented database designed for real-time analytics. Here's why it's compelling for financial data:
Performance
In our benchmarks on tick data workloads, ClickHouse typically achieves 70-90% of KDB+ query performance—and sometimes exceeds it for certain query patterns. For most use cases, this is more than sufficient.
Query: VWAP calculation on 1 billion trades
KDB+: 0.8 seconds
ClickHouse: 1.1 seconds
Cost
ClickHouse is open-source with a permissive Apache 2.0 license. The managed ClickHouse Cloud service is available, but you can also run it yourself on commodity hardware. A typical migration saves 60-80% on database costs.
Accessibility
ClickHouse uses SQL. Your existing team already knows it. Hiring is straightforward. Onboarding new developers takes days, not months.
Modern Architecture
ClickHouse includes:
- •Built-in replication and sharding
- •Integration with Kafka, S3, and other data sources
- •Prometheus metrics and modern observability
- •Docker and Kubernetes support
- •Active open-source community
Migration Strategy
We've developed a proven migration methodology:
- 1.Schema Translation: Map KDB+ tables to ClickHouse with appropriate data types and partitioning
- 2.Query Migration: Convert q queries to SQL, optimizing for ClickHouse query patterns
- 3.Data Migration: Parallel export/import with validation
- 4.Performance Tuning: Optimize table engines, indices, and materialized views
- 5.Parallel Running: Run both systems in parallel during transition
When to Stick with KDB+
KDB+ remains the right choice when:
- •You need absolute lowest latency (sub-millisecond query times)
- •You have existing q expertise and codebase investment
- •Your use case requires complex vector operations that q handles elegantly
- •Cost is not a primary concern
Conclusion
For most financial firms, ClickHouse offers the best balance of performance, cost, and operational simplicity. If you're evaluating options for a new market data platform or considering a KDB+ migration, we'd be happy to share our experience and help you make the right decision.