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Maximum Message Size

The default maximum message size is 1MB. There's a way to increase this limit in case you want to, but please think it through before doing so.

The max message size is determined by:

  • Max messages size supported by gRPC (default value is 64MB in Numaflow).
  • Max messages size supported by the Inter-Step Buffer implementation.

If JetStream is used as the Inter-Step Buffer implementation, the default max message size for it is configured as 1MB. You can change it by setting the spec.jetstream.settings in the InterStepBufferService specification.

kind: InterStepBufferService
  name: default
    settings: |
      max_payload: 8388608 # 8MB

It's not recommended to use values over 8388608 (8MB) but max_payload can be set up to 67108864 (64MB).

Please be aware that if you increase the max message size of the InterStepBufferService, you probably will also need to change some other limits. For example, if the size of each messages is as large as 8MB, then 100 messages flowing in the pipeline will make each of the Inter-Step Buffer need at least 800MB of disk space to store the messages, and the memory consumption will also be high, that will probably cause the Inter-Step Buffer Service to crash. In that case, you might need to update the retention policy in the Inter-Step Buffer Service to make sure the messages are not stored for too long. Check out the Inter-Step Buffer Service for more details.