Real-Time Serving Layer
Where a low-latency read of a streaming aggregate actually lands.
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This topic is part of the curriculum but has no questions, cards or glossary entries so far. The rest of Streaming & Real-Time Data may still cover what you are looking for.
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Streaming & Real-Time Data
General material on continuous processing of unbounded data.
No content yetStreaming vs Batch
The freshness requirement that actually justifies streaming, and the cost of assuming one.
No content yetExactly-Once Semantics
What the phrase really means, where it holds, and the idempotent sink underneath it.
No content yetStream Processing Frameworks
Flink, Kafka Streams, Spark Structured Streaming — state, checkpointing and recovery.
Windowing
Tumbling, sliding and session windows, and the aggregation each one answers.
No content yetWatermarks & Late Data
Deciding a window is complete when events can still arrive, and what to do when they do.
No content yetStateful Stream Processing
Keyed state, state backends, checkpoint size, and the restore time that follows.
No content yetStream-Table Duality
A changelog and a table as two views of the same thing, and materialising between them.
No content yetKappa vs Lambda
One pipeline replayed versus two pipelines reconciled, and the maintenance each carries.
No content yetStreaming Schema Evolution
Changing an event's shape while a retained log still holds every older version of it.
No content yetStreaming Joins
Joining two unbounded streams, the buffering it needs, and the enrichment alternative.
No content yetBackfill & Reprocessing
Replaying history through changed logic without double-counting the live output.
No content yetCDC to Stream
Turning database changes into an event log, and how that differs from a domain event.
No content yetFeature Freshness
How stale a feature can be before the model degrades, and the pipeline that follows.
No content yetStreaming SLOs
End-to-end latency, consumer lag and completeness as commitments rather than dashboards.
No content yetPartition Keys & Ordering
Ordering guaranteed only within a partition, and choosing the key that makes that enough.
No content yetDead Letter Handling
The poison message that blocks a partition, and the queue nobody reads.
No content yetStreaming Cost
Always-on compute, retention and cross-zone traffic as the three bills that surprise.
No content yetReal-Time Analytical Stores
Druid, Pinot and ClickHouse — ingest-and-query engines for sub-second aggregation.
No content yet