Streaming Output Modes: Append vs Complete vs Update

How can we select the correct output mode for streaming stateful aggregations vs simple row transformations?

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🤔 THE QUESTION

How can we select the correct output mode for streaming stateful aggregations vs simple row transformations?

💡 WHAT IS IT?

outputMode('append') outputs new rows; 'complete' outputs the entire aggregated result table; 'update' outputs only modified rows.

🎯 WHAT IS IT USED FOR?

Writing incremental event feeds ('append') vs publishing live KPI counter dashboards ('update' or 'complete').

💻 EXAMPLE

query_update = streaming_counts.writeStream.outputMode("update").format("console").option("checkpointLocation", "/tmp/checkpoints/update/").start()

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