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Data Pipeline Architecture Questions

Design end to end data pipeline solutions from problem statement through implementation and operations, integrating ingestion transformation storage serving and consumption layers. Topics include source selection and connectors, ingestion patterns including batch streaming and micro batch, transformation steps such as cleaning enrichment aggregation and filtering, and loading targets such as analytic databases data warehouses data lakes or operational stores. Cover architecture patterns and trade offs including lambda kappa and micro batch, delivery semantics and fault tolerance, partitioning and scaling strategies, schema evolution and data modeling for analytic and operational consumers, and choices driven by freshness latency throughput cost and operational complexity. Operational concerns include orchestration and scheduling, reliability considerations such as error handling retries idempotence and backpressure, monitoring and alerting, deployment and runbook planning, and how components work together as a coherent maintainable system. Interview focus is on turning requirements into concrete architectures, technology selection, and trade off reasoning.

EasyTechnical
61 practiced
Given a table transactions(transaction_id STRING PRIMARY KEY, user_id INT, occurred_at TIMESTAMP, event_type STRING), write a standard SQL query to compute Daily Active Users (DAU) for the last 30 days grouped by UTC date. Deduplicate multiple events per user per day (count each user once per UTC day) and show output columns: date, dau.
EasyTechnical
55 practiced
Compare batch and streaming ingestion patterns used in data pipelines. For each pattern describe typical use cases, freshness/latency implications, common tools (examples: Airflow, Spark batch, Kafka, Flink, Pub/Sub), failure and replay behavior, and a rule-of-thumb for choosing between them based on product requirements.
MediumTechnical
85 practiced
You must integrate multiple source systems into your pipelines: Postgres OLTP, Salesforce, and a third-party SFTP feed. Compare connector choices (Debezium/CDC for Postgres, managed connectors for Salesforce, bespoke SFTP ingestion), discuss consistency and latency guarantees, operational overhead, and approaches to validate correctness after ingestion.
HardSystem Design
62 practiced
Design a CDC pipeline that consolidates changes from multiple OLTP databases (Postgres, MySQL) into a central analytics warehouse. Ensure transactional order per source, support schema changes, minimize latency, and allow for reprocessing from an LSN/offset. Describe message bus partitioning, ordering guarantees, and consumer-side logic for consistent application.
HardSystem Design
57 practiced
Design a cost-optimized architecture to ingest and store 5 PB/year of data while providing queryable analytics with average query latency under 2 seconds for common OLAP queries. Discuss file formats, partitioning strategies, storage tiering (hot/warm/cold), caching, materialized views, pre-aggregation, and trade-offs between storage and compute costs.

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