Dataford
Interview QuestionsInterview GuidesExperiencesCoaching
New
Pricing
Get started
Dataford
Popular roles
Software EngineerData AnalystData ScientistData EngineerBusiness AnalystAI EngineerMachine Learning EngineerProduct Manager
Browse
Browse All RolesEvery role hub, from analyst to MLBrowse All CompaniesCompany-specific interview loopsAll Interview GuidesThe full guide library
Top questions by role
Software EngineerData AnalystData ScientistData EngineerBusiness AnalystAI EngineerMachine Learning EngineerProduct Manager
Top questions by skill
SQLPythonStatisticsMachine LearningA/B TestingSystem DesignGenerative AIProduct SenseMetricsBehavioral
Browse all questions →Try a mock interview
Experiences
Practice
Mock InterviewsTimed interview simulations with feedbackCoaching1:1 coaching with people at your target companiesSuccess PathYour 6-week structured planModulesCurated lessons by topicWebinarsTalks from ex-Big Tech data leadsPlaygroundA free-form scratch editor
Learn
BlogInterview strategy and career adviceTech Job Market ReportHiring trends across data and AI rolesFor UniversitiesDataford for career centersAbout DatafordWho we are and how we build
Pricing
Build my plan

Design ETL Pipeline for Retail Sales Data

MediumPipelines00:00
Practice interviewer
In session
5 left
00:00

Your question is Design ETL Pipeline for Retail Sales Data. Take a moment with it on the right.

Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).

You need to log in / sign up to chat or submit.

Problem

Context

RetailCorp, a leading retail chain, processes over 10 million transactions daily across its online and physical stores. Currently, the company uses a nightly batch ETL process to load sales data into its data warehouse, resulting in significant delays for reporting and analytics. To enhance operational efficiency and decision-making, the VP of Data Engineering has mandated the creation of a real-time ETL pipeline.

Scale Requirements

  • Throughput: Process 10 million transactions daily (~115 transactions/sec peak).
  • Latency target: Data should be available for querying in the data warehouse within 5 minutes of the transaction occurring.
  • Storage: Store raw and transformed data in a cloud-based data warehouse, with retention of raw data for 90 days and aggregated data indefinitely.

Requirements

  1. Design a real-time ingestion pipeline that captures sales transactions from multiple sources (POS systems, e-commerce platforms).
  2. Implement data quality checks to validate transaction data (e.g., schema validation, duplicate detection).
  3. Transform data into a structured format suitable for analytics (e.g., aggregating daily sales, calculating metrics).
  4. Load transformed data into a cloud-based data warehouse (e.g., Snowflake) with < 5 minute latency.
  5. Create monitoring and alerting mechanisms for data quality and pipeline performance.

Constraints

  • Team: 5 data engineers with expertise in AWS and SQL but limited experience in streaming technologies.
  • Infrastructure: AWS-based (existing S3, Redshift).
  • Budget: $20K/month for cloud services.