Problem Description:
We encountered an issue with the PMM (Percona Monitoring and Management) QAN module. Specifically, when executing the same SQL query in different databases within the same MySQL database instance, the QAN module’s query statistics are inconsistent and incomplete.
- For the same SQL query, the QAN module reports fewer executions or misses some queries entirely across different databases within the same instance.
- This issue significantly affects our ability to monitor and optimize query performance, especially in a sharded architecture where accurate statistics are crucial for query optimization.
Background Information:
- We submitted the bug report on August 11, 2023, detailing the issue of inconsistent query statistics across databases within the same instance. However, we have not seen any progress or resolution after nearly two years.
- Since we rely heavily on a sharded architecture, this issue has seriously impacted our ability to use PMM QAN for database performance monitoring. While PMM offers great features, this bug has made it difficult for us to rely on its query analytics functionality.
Bug Submission Link:
- Bug Submission: PMM-12413
Expected Behavior:
- We expect the PMM QAN module to provide consistent query statistics across databases within the same instance when executing the same SQL query.
- We hope that this bug can be resolved quickly, ensuring accurate query analysis in sharded environments.
If anyone has any temporary solutions or techniques to avoid the impact of this bug on statistics, we would greatly appreciate your input!
Additional Information:
- PMM Version: 2.42.0
- Database: MySQL 5.7/8.0
- OS: CentOS 7