Simulating Real Time Streaming in Databricks free edition

[ManojkMohan]

Use Case:

1. Kafka real time steaming network telemetry logs
2. In a real use case approx. 40 TB of data can be real time streamed in a day

Architecture:

issue encountered:  when i try to simulate kakfa like streaming in databricks itself , as this is a free editon and i am using serverless compute i am getting error

[INFINITE_STREAMING_TRIGGER_NOT_SUPPORTED] Trigger type ProcessingTime is not supported for this cluster type. Use a different trigger type e.g. AvailableNow, Once. SQLSTATE: 0A000

Code:

from pyspark.sql.functions import col, expr

# Generate 1000 rows per second

streamingDF = (spark.readStream

               .format("rate")

               .option("rowsPerSecond", 1000)

               .load())

# Add simulated IoT telemetry fields

telemetryDF = streamingDF.withColumn("tower_id", (col("value") % 50_000)) \

                         .withColumn("metric", expr("rand() * 100")) \

                         .withColumn("region", expr("CASE WHEN tower_id % 5 = 0 THEN 'North' ELSE 'South' END"))

# Write to Delta (simulated Bronze table)

query = (telemetryDF.writeStream

         .format("delta")

         .outputMode("append")

         .option("checkpointLocation", "/tmp/telemetry_checkpoints")

         .option("path", "/tmp/telemetry_bronze")

         .start())

Any suggestions for a work around

[szymon_dybczak]

Hi @ManojkMohan ,

Unfortunately there is no workaround here. Free Edition supports only serverless compute. And serverless has following streaming limitation - one of which you just encountered - there is no support for default or time-based trigger intervals:

You can still run your code but you need to provide supported trigger (for instance availableNow)

query = (telemetryDF.writeStream
         .format("delta")
         .outputMode("append")
         .option("checkpointLocation", "/tmp/telemetry_checkpoints")
         .option("path", "/tmp/telemetry_bronze")
         .trigger(availableNow=True)  # Process all available data now
         .start())

If you want to POC other streaming triggers you need to either have access to Databricks Premium workspace with classic compute or just download OSS Apache Spark docker container.