[skip-ci] fix: TSDB metric collection & config load from disk

[wazir-ahmed]

• tsdb_sampler_loop() calls registry->Collect() without refreshing module metrics, causing stale metric values to be stored in the TSDB. Added update_modules_metrics() call before Collect() in the sampler.

• TSDB variables stored on disk were not being loaded into runtime during startup. Added the missing flush_tsdb_variables___database_to_runtime() and invoke it during init.

Summary by CodeRabbit

• New Features

  • Prometheus metrics are now automatically refreshed before collection.

• Refactor

  • TSDB variable initialization refactored to use unified synchronization approach.
  • TSDB variable handling consolidated for improved consistency across startup sequences.

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[gemini-code-assist]

Summary of Changes

Hello @wazir-ahmed, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves two key issues within ProxySQL's Time Series Database (TSDB) functionality. It guarantees the accuracy of collected metrics by ensuring all module metrics are updated prior to TSDB collection. Furthermore, it rectifies a problem where TSDB-related configuration variables stored on disk were not being loaded into the runtime during initialization, thereby ensuring proper application and persistence of these settings across restarts.

Highlights

• TSDB Metric Freshness: Ensured that Prometheus module metrics are refreshed immediately before collection in the TSDB sampler loop, preventing stale data from being stored.
• TSDB Variable Persistence: Implemented the loading of TSDB configuration variables from disk into the runtime environment during application startup, addressing an oversight where these settings were not being applied.

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Changelog

• include/proxysql_admin.h
  • Declared a new function update_modules_metrics() for refreshing Prometheus metrics.
  • Refactored load_tsdb_variables_to_runtime() and save_tsdb_variables_from_runtime() to use generic flush functions, simplifying their implementation.
• lib/Admin_Bootstrap.cpp
  • Added a call to flush_tsdb_variables___database_to_runtime() to ensure TSDB variables are loaded during the admin initialization process.
• lib/Admin_FlushVariables.cpp
  • Extended the generic variable flushing mechanism to correctly handle tsdb module variables for both setting and getting.
  • Implemented the flush_tsdb_variables___database_to_runtime() function to manage loading TSDB variables from the database.
• lib/ProxySQL_Admin.cpp
  • Removed the explicit implementations of load_tsdb_variables_to_runtime() and save_tsdb_variables_from_runtime(), as their logic is now handled by the refactored generic flush functions and inline definitions.
• lib/ProxySQL_Statistics.cpp
  • Inserted a call to update_modules_metrics() within the tsdb_sampler_loop() to ensure all module metrics are current before Prometheus collection.

Activity

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Code Review

This pull request addresses two issues with the TSDB functionality. First, it ensures that metrics are refreshed before collection in the TSDB sampler loop by adding a call to update_modules_metrics(), preventing stale data from being stored. Second, it fixes a bug where TSDB configuration variables were not loaded from disk on startup by adding the necessary flush_tsdb_variables___database_to_runtime() call during initialization. The changes also include a refactoring of TSDB variable handling to use generic flushing functions, which improves code consistency and maintainability. The fixes appear correct and well-implemented.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud