Limitations

The following limitations apply to Atlas Stream Processing:

• The combined state.stateSize of all stream processing instances can't exceed 80% of the RAM available for a worker in the same SPI tier. For example, the maximum size of a stream processor in the SP30 tier which has 8GB of RAM per worker, is 6.4GB. If the state.stateSize of any of your stream processors is approaching 80% of the RAM available for a worker in the same SPI tier, move up to the next SPI tier.

  When the 80% RAM threshold has been crossed, all stream processors fail with a stream processing instance out of memory error. You can view the state.stateSize value of each stream processor with the sp.processor.stats() command. See View Statistics of a Stream Processor to learn more.

• A stream processing instance can use only clusters in the same project as sources or sinks.

• An Atlas Stream Processing pipeline definition cannot exceed 16 MB.

• Only users with the Project Owner or Atlas admin roles can use Atlas Stream Processing.

• Atlas Stream Processing currently supports only the following connection types:

  Connection Type	Usage
  Apache Kafka	Source or Sink
  Atlas Database	Source or Sink
  Sample Connection	Source Only

• For Atlas Stream Processing using Apache Kafka as a $source, if the Apache Kafka topic acting as $source to the running processor adds a partition, Atlas Stream Processing continues running without reading the partition. The processor fails when it detects the new partition after you restore it from a checkpoint after a failure, or you restart it after stopping it. You must recreate the processors that read from topics with the newly added partitions.

• Atlas Stream Processing currently supports only JSON-formatted data. It does not currently support alternative serializations such as Avro or Protocol Buffers.

• For Apache Kafka connections, Atlas Stream Processing currently supports only the following security protocols:

  • SASL_PLAINTEXT

  • SASL_SSL

  • SSL

  For SASL, Atlas Stream Processing supports the following mechanisms:

  • PLAIN

  • SCRAM-SHA-256

  • SCRAM-SHA-512

  • OAUTHBEARER

  For SSL, you must provide the following assets for your Apache Kafka system mutual TLS authentication with Atlas Stream Processing:

  • a Certificate Authority (if you are using one other than the default Apache Kafka CA)

  • a client TLS certificate

  • a TLS keyfile, used to sign your TLS certificate

• Atlas Stream Processing doesn't support $function JavaScript UDFs.

• Atlas Stream Processing supports a subset of the Aggregation Pipeline Stages available in Atlas, allowing you to perform many of the same operations on streaming data that you can perform on data-at-rest. For a full list of supported Aggregation Pipeline Stages, see the Stream Aggregation documentation.

• Atlas Stream Processing doesn't support the aggregation variables $$NOW, $$CLUSTER_TIME, $$USER_ROLES, and $SEARCH_META.