Google Professional Data Engineer Question 250
Select 4Google Cloud PlatformYou are a Data Engineer responsible for managing a real-time data pipeline on Google Cloud. The pipeline processes streaming data using Dataflow and writes the results to BigQuery. Recently, you noticed delays in processing and incomplete data in BigQuery. Which steps should you take to effectively diagnose and troubleshoot the issue?
- A
Check the Dataflow job's worker logs for errors or warnings.
- B
Verify the BigQuery dataset permissions to ensure the Dataflow job can write to it.
- C
Increase the maximum number of workers in the Dataflow job without analyzing the root cause.
- D
Examine the Dataflow job's metrics, such as system lag and throughput, in Cloud Monitoring.
- E
Inspect the Pub/Sub subscription backlog for the input topic feeding the Dataflow pipeline.
Show answer and explanation
Correct answers: A, B, D, E
Explanation
Diagnosing and troubleshooting delays or incomplete data in a Dataflow pipeline requires a systematic approach. Checking the worker logs, permissions, and metrics helps identify potential issues with the pipeline's processing and writing stages. Analyzing the Pub/Sub subscription backlog provides insights into upstream data ingestion. Arbitrary changes, like increasing workers, should only be made after understanding the root cause to avoid unnecessary costs and inefficiencies.
- A. Correct.
Checking the Dataflow job's worker logs can reveal errors or warnings that are causing delays or incomplete data, making it a crucial troubleshooting step.
- B. Correct.
Verifying BigQuery dataset permissions ensures the Dataflow job has the necessary access to write data. Permission issues can result in incomplete data.
- C. Incorrect.
Simply increasing the number of workers without understanding the underlying issue doesn't address the root cause and may waste resources. This is not a recommended first step.
- D. Correct.
Examining metrics like system lag and throughput in Cloud Monitoring can help you understand where bottlenecks are occurring in the pipeline.
- E. Correct.
Inspecting the Pub/Sub subscription backlog can indicate whether the pipeline is receiving data slower than expected, which may point to upstream or processing issues.