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How does Auto Loader avoid reloading files with the same name?

Spark/Big Datahard0.6 min readPremium
Frequency
Low
Asked at 1 company
Category
452
questions in Spark/Big Data
Difficulty Split
88E|81M|283H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
TCS
Key Concepts Tested
optimizationpartition
Expert AnswerPremium
120 wordsInterview-ready
**Why it matters**: At scale, design choices directly impact reliability, latency, and cost. Wrong decisions compound across jobs and teams. Auto Loader uses a cloud-based file notification service (e.g., S3 event notifications, GCS Pub/Sub) or directory listing to track which files were already processed. It maintains a checkpoint (default: `_checkpoints/`) with file paths and modification times....
The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations. It covers performance optimization strategies, common pitfalls to avoid, and real-world examples from companies like TCS. The answer also includes follow-up discussion points that interviewers commonly explore.

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