DataEngPrep.tech
QuestionsPracticeAI CoachDashboardPacksBlog
ProLogin
Home/Questions/System Design/Architecture/Describe a scenario where you had to optimize a slow-running data pipeline.

Describe a scenario where you had to optimize a slow-running data pipeline.

System Design/Architecturemedium0.2 min readPremium

**STAR**: **Situation**: Nightly job took 6 hr; SLA 2 hr. **Task**: Optimize. **Action**: Profiled—found full scan and skew. Partition pruning; broadcast join for dimension; salting for skew. **Result**: 1.5 hr; 4x improvement....

🤖 Analyze Your Answer
Frequency
Low
Asked at 1 company
Category
179
questions in System Design/Architecture
Difficulty Split
15E|6M|158H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
Swiggy
Interview Pro Tip

Pro-Move: 'Spark UI showed 1 partition at 4hr—salted the key, added pruning; 6hr to 90min; documented in runbook.' Red Flag: We added more resources—optimization, not scaling.

Key Concepts Tested
joinpartition

Why This Question Matters

This medium-level System Design/Architecture question appears frequently in data engineering interviews at companies like Swiggy. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (join, partition) will help you answer variations of this question confidently.

How to Approach This

Break this problem into components. Identify the core trade-offs involved, then walk the interviewer through your reasoning step by step. Demonstrate awareness of edge cases and production considerations - this is what separates good answers from great ones.

Expert Answer
35 words

STAR: Situation: Nightly job took 6 hr; SLA 2 hr. Task: Optimize. Action: Profiled—found full scan and skew. Partition pruning; broadcast join for dimension; salting for skew. Result: 1.5 hr; 4x improvement. Quantify: Before/after; techniques.

The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations covering performance optimization and real-world examples.

This answer is partially locked

Unlock the full expert answer with code examples and trade-offs

Recommended

Start AI Mock Interview

Practice real interviews with AI feedback, track progress, and get interview-ready faster.

  • Unlimited AI mock interviews
  • Instant feedback & scoring
  • Full answers to 1,800+ questions
  • Resume analyzer & SQL playground
Create Free Account

Pro starts at $24/mo - cancel anytime

Just need answers for quick revision?

Download curated PDF interview packs

Interview Packs
1,800+ real interview questions sourced from 5 top companies
AmazonGoogleDatabricksSnowflakeMeta
This answer is in the DE Mastery Vault 2026
1,863 questions with expert answers across 7 categories →

Related System Design/Architecture Questions

hardWhat architecture are you following in your current project, and why?FreeeasyCDC During Migration - explain approaches for real-time Change Data CaptureFreehardBriefly explain the architecture of Kafka.FreehardDescribe the data pipeline architecture you've worked with.FreehardExplain the trade-offs between batch and real-time data processing. Provide examples of when each is appropriate.Free

Want to know if YOUR answer is good enough?

Paste your answer and get instant AI feedback with a FAANG-level improved version.

Analyze My Answer — Free

According to DataEngPrep.tech, this is one of the most frequently asked System Design/Architecture interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.

← Back to all questionsMore System Design/Architecture questions →