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Vibe codingMediumvc-g512
Subject Ai code reviewLevel Mid–Senior~16 minCommon in Distributed systems interviewsIndustries Software development, Technology

Question

This Lambda (Python) was generated to count rows in a CSV that S3 events deliver. It works for sample files and crashes with out-of-memory on real uploads. Identify the bug and the fix.

python
import boto3s3 = boto3.client("s3") def handler(event, context):    rec = event["Records"][0]["s3"]    bucket, key = rec["bucket"]["name"], rec["object"]["key"]    obj = s3.get_object(Bucket=bucket, Key=key)    data = obj["Body"].read().decode("utf-8")    rows = data.splitlines()    return {"row_count": len(rows)}
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