ksqlDB is a database purpose-built to help developers
create stream processing applications on top of Apache Kafka®. Confluent Cloud provides a
fully managed solution for creating and managing ksqlDB applications and
Confluent Cloud ksqlDB
You can provision ksqlDB applications by using the Confluent Cloud UI or the ccloud
For more information, see Confluent Cloud ksqlDB Quick Start.
Supported Features for ksqlDB in Confluent Cloud
- Web interface for managing your ksqlDB cloud environment directly from your
browser that exposes all critical ksqlDB information.
- SQL editor to write, develop, and execute SQL queries with auto completion
directly from the Web interface.
- Integration with Confluent Cloud Schema Registry to leverage your existing schemas to use within
your SQL queries.
- Available in AWS, GCP, and Azure in all regions.
New Features for ksqlDB in Confluent Cloud
For the latest features in ksqlDB, see the
Limitations for ksqlDB in Confluent Cloud
- Currently, user-defined functions (UDFs, UDAFs, and UDTFs) aren’t supported.
For more information, see Functions.
- You can have a maximum of 20 persistent queries
- You can have a maximum of three ksqlDB applications. For more information,
see Create a ksqlDB application in Confluent Cloud.
- Pull queries are in preview.
The number of concurrent pull queries is limited to 10.
- SQL-based Connect integration isn’t supported.
- ccloud CLI version 0.198.0 or higher is required to create ksqlDB API
keys for Confluent Cloud.
Pricing for ksqlDB in Confluent Cloud
The unit of pricing in Confluent Cloud ksqlDB is the Confluent Streaming Unit. A Confluent Streaming Unit
is an abstract unit that represents the linearity of performance.
For example, if a workload gets a certain level of throughput with four CSUs, you
can expect about three times the throughput with 12 CSUs.
Confluent charges you in CSUs per hour.
You select the number of CSUs for your application at provisioning time.
You can configure CSUs in blocks of four.
- 4 CSUs is the minimum.
- 12 CSUs is the initial maximum.
- Your application can have 4, 8, or 12 CSUs.
- Applications with greater than 4 CSUs are automatically configured for high availability.
- High availability cannot be enabled for applications with 4 CSUs.
Confluent Streaming Unit pricing varies slightly depending on cloud provider and region. Pricing
is shown in the web interface as part of ksqlDB provisioning so that you can
see exact pricing for your cloud and region of choice.
Scaling CSUs for ksqlDB in Confluent Cloud
Scaling your application’s CSUs after initial provisioning is not supported.
If you determine that your application requires more CSUs, you must provision
a new application with the desired number of CSUs, and migrate to your new one.
Sizing guidelines for ksqlDB in Confluent Cloud
Four CSUs are sufficient for many workloads. In general, start with four CSUs
and scale out if more capacity is needed. To identify when more CSUs are needed,
check ksqlDB consumer lag. For more information, see
Monitor persistent queries.
After your ksqlDB application is provisioned, you can only change the Confluent Streaming Unit
allocation by migrating to a new one one with the desired number of CSUs.