To troubleshoot query performance issues related to job queuing or slot contention in BigQuery, using administrative resource charts along with querying the INFORMATION_SCHEMA is the best approach.
Here's why option D is the best choice:
* Administrative Resource Charts:
* BigQuery provides detailed resource charts that show slot usage and job performance over time.
These charts help identify patterns of slot contention and peak usage times.
* INFORMATION_SCHEMA Queries:
* The INFORMATION_SCHEMA tables in BigQuery provide detailed metadata about query jobs, including execution times, slots consumed, and other performance metrics.
* Running queries on INFORMATION_SCHEMA allows you to pinpoint specific jobs causing contention and analyze their performance characteristics.
* Comprehensive Analysis:
* Combining administrative resource charts with detailed queries on INFORMATION_SCHEMA provides a holistic view of the system's performance.
* This approach enables you to identify and address the root causes of performance issues, whether they are due to slot contention, inefficient queries, or other factors.
Steps to Implement:
* Access Administrative Resource Charts:
* Use the Google Cloud Console to view BigQuery's administrative resource charts. These charts provide insights into slot utilization and job performance metrics over time.
* Run INFORMATION_SCHEMA Queries:
* Execute queries on BigQuery's INFORMATION_SCHEMA to gather detailed information about job performance. For example:
SELECT
creation_time,
job_id,
user_email,
query,
total_slot_ms / 1000 AS slot_seconds,
total_bytes_processed / (1024 * 1024 * 1024) AS processed_gb,
total_bytes_billed / (1024 * 1024 * 1024) AS billed_gb
FROM
`region-us`.INFORMATION_SCHEMA.JOBS_BY_PROJECT
WHERE
creation_time > TIMESTAMP_SUB(CURRENT_TIMESTAMP(), INTERVAL 1 DAY)
AND state = 'DONE'
ORDER BY
slot_seconds DESC
LIMIT 100;
* Analyze and Optimize:
* Use the information gathered to identify bottlenecks, optimize queries, and adjust resource allocations as needed to improve performance.
Reference Links:
* Monitoring BigQuery Slots
* BigQuery INFORMATION_SCHEMA
* BigQuery Performance Best Practices