1. CDC to Stream intermediate

    A CDC connector on a 4 TB Postgres table is restarted with a changed configuration during business hours, and the operator does not realise this triggers a new initial snapshot. What happens over the next three hours, upstream and downstream?

    3 min answer cdcsnapshotreplication slotbackpressure
  2. Dead Letter Handling intermediate

    A streaming pipeline sends failed messages to a dead-letter queue. What makes that a real control rather than a data-loss mechanism?

    2 min answer segmentdead-letterpoisonownership
  3. Dead Letter Handling intermediate

    How should unprocessable messages be handled, and what makes dead-letter handling useful rather than a graveyard?

    2 min answer dead-letterpoison-messagesreplayvisibility
  4. Dead Letter Handling intermediate

    You find 40,000 messages in a dead letter queue, the oldest from seven months ago. Nobody knew. What do you fix?

    2 min answer messagingoperationsdata-loss
  5. Partition Keys & Ordering intermediate

    A team must choose partition keys for an event stream. What does the choice determine, and what goes wrong when it is chosen carelessly?

    2 min answer partitioningorderinghot-keyparallelism
  6. Partition Keys & Ordering intermediate Multiple choice

    After scaling consumers from 3 to 12, downstream data shows updates applied out of order. What happened?

    2 min answer orderingpartitioningcorrectness
  7. Real-Time Serving Layer intermediate Multiple choice

    A product page needs the current computed price for one product id at 40,000 reads per second with p99 under 25 ms. A stream processor already recomputes each product's price every few seconds from competitor and inventory events. Where should the read path go?

    3 min answer serving-layerkey-valuequeryable-stateolap
  8. Real-Time Analytical Stores intermediate Multiple choice

    A creator analytics feature must show per-minute view counts for 8 million creators over a 90-day window at p95 under 500 ms while ingesting 300 thousand view events per second. Work out the row counts and decide which storage shape fits.

    3 min answer rollupretentioncolumnarsizing
  9. Real-Time Analytical Stores intermediate Multiple choice

    A team proposes a specialised real-time analytics store for an internal dashboard used by twelve analysts. Assess.

    2 min answer architecturecostdecision
  10. Stream Processing Frameworks intermediate Multiple choice

    A team must join an order stream keyed by order id to a payment stream that carries order id but is keyed by payment id, with 12 partitions on one topic and 48 on the other, matching within seven days and with a standing requirement to reprocess the last 30 days after a logic fix. Which runtime fits and what is the deciding property?

    3 min answer flinkkafka streamscopartitioningstate
  11. Stream-Table Duality intermediate

    Review this design. Each of 18 services embeds a Kafka Streams GlobalKTable of a 9-million-row customer topic so that lookups are local, each instance holding it in RocksDB on local disk. Instances take 11 minutes to become ready. What would you remove, what would you change, and what would you leave alone even though it looks odd?

    3 min answer globalktablematerialised viewrestore timedeploys
  12. Streaming Cost intermediate

    A marketplace platform at Flipkart's scale runs three separate Kafka clusters for orders, device telemetry and experimentation. Consolidating them into one shared cluster cuts the infrastructure bill by about 40%. What did that 40% buy, and when does the bill arrive?

    2 min answer flipkartmulti-tenancyquotasstreaming-cost