DEA-C01 Data Operations and Support Practice Question

A data engineer is troubleshooting an AWS Glue ETL job that fails intermittently with the error 'Rate exceeded.' The job reads from an Amazon RDS for MySQL source and writes to Amazon S3. What is the MOST likely cause of this error?

⚠ Common exam trap

The trap is assuming the error comes from the target (S3) or from a misconfigured IAM role; candidates must recognize that 'Rate exceeded' often points to source database connection limits when using JDBC sources like RDS.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The number of Glue job workers or parallel queries is exceeding the maximum connections or IOPS of the RDS instance.

The 'Rate exceeded' error in AWS Glue typically occurs when the job opens too many concurrent connections to the source database. With RDS for MySQL, each Glue worker or parallel read task establishes a connection, and exceeding the instance's max_connections or IOPS limits triggers throttling. This is the most likely cause when reading from RDS and writing to S3.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
The Glue job is using Amazon Kinesis Data Streams as a source, which has a shard throughput limit.
Why it's wrong here
The stem specifies Amazon RDS for MySQL as the source, so Kinesis shard throughput cannot produce this error. Kinesis Data Streams is the right choice when ingesting real-time streaming data, where each shard's 1 MB/s ingest limit genuinely triggers 'Rate exceeded' during scaling.
✓
The number of Glue job workers or parallel queries is exceeding the maximum connections or IOPS of the RDS instance.
Why this is correct
Glue workers open concurrent JDBC connections to the RDS for MySQL source. When worker count or parallel read queries exceed the instance's maximum connections or provisioned IOPS, the source rejects requests, surfacing as 'Rate exceeded' — an RDS-side throttling limit, not a Glue service quota.
✗
The Amazon S3 bucket has a bucket policy that limits the number of objects written per second.
Why it's wrong here
S3 bucket policies govern access permissions, not request rates; S3 scales request throughput per prefix automatically, so no policy caps objects written per second. Bucket policies are the correct control when restricting which principals or VPC endpoints may access specific prefixes.
✗
The IAM role attached to the Glue job does not have sufficient permissions to read from RDS.
Why it's wrong here
Missing IAM permissions return AccessDenied errors, not 'Rate exceeded'. IAM roles are the right mechanism when the job needs scoped, temporary credentials to call AWS services — but throttling stems from exceeding API request quotas, not from authorisation gaps.

Quick reference

AWS S3 Storage Class Comparison

Storage Class	Min Duration	Retrieval	Use Case
S3 Standard	None	Immediate	Frequently accessed data
S3 Standard-IA	30 days	Immediate	Infrequent access, rapid retrieval
S3 One Zone-IA	30 days	Immediate	Non-critical infrequent data
S3 Intelligent-Tiering	None	Immediate–hours	Unknown or changing access patterns
S3 Glacier Instant	90 days	Milliseconds	Archive with instant retrieval
S3 Glacier Flexible	90 days	Minutes–hours	Archive, flexible retrieval
S3 Glacier Deep Archive	180 days	Hours	Long-term compliance archive

Go deeper

DEA-C01 Data Operations and Support Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

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