Group Replication support for MySQL 8.4 and 9.x

[renecannao]

Closes #4954

[gemini-code-assist]

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Summary of Changes

Hello! Gemini here, providing a summary of this pull request. This PR, authored by @renecannao, aims to extend or improve support for MySQL Group Replication, specifically targeting compatibility with newer MySQL versions like 8.4 and potential future 9.x releases. The core change involves updating the logic used to determine which Group Replication query to execute based on the MySQL server version. Instead of a simple string comparison checking if the version starts with '8', the code now uses mysql_get_server_version to get the version as an integer and checks if it's greater than or equal to 80000 (representing version 8.0.0). This makes the version check more robust and forward-compatible.

Highlights

• MySQL Version Check Improvement: The method for checking the MySQL server version to select the appropriate Group Replication query has been updated from a string comparison (strncasecmp) to using mysql_get_server_version and comparing the integer value. This is a more reliable way to handle version checks.
• Extended Group Replication Support: By using a more robust version check (>= 80000), the code is better equipped to handle MySQL versions 8.0 and above, including 8.4 and potentially future 9.x releases, ensuring continued support for Group Replication monitoring.

Changelog

• lib/MySQL_Monitor.cpp
  • Updated the MySQL server version check logic for Group Replication queries to use mysql_get_server_version(mysql) >= 80000 instead of strncasecmp(this->mysql->server_version, "8", 1) == 0 (lines 698-699).
  • Slightly adjusted a comment related to the MySQL 8 query dependency (line 696).

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[gemini-code-assist]

Code Review

This pull request introduces a more robust method for checking the MySQL server version when selecting the appropriate Group Replication query. The change from strncasecmp to mysql_get_server_version is a clear improvement for correctness and future maintainability, especially for upcoming versions like MySQL 8.4 and 9.x. The accompanying comment update also slightly enhances clarity. Overall, this is a good, focused change that improves the codebase.

Summary of Findings

• Improved MySQL Version Checking: The primary change updates the MySQL version check from strncasecmp(this->mysql->server_version, "8", 1) == 0 to mysql_get_server_version(mysql) >= 80000. This is a significant improvement because mysql_get_server_version() provides a numerical representation of the version, allowing for more precise and reliable comparisons (e.g., distinguishing 8.x from a hypothetical 80.x). This makes the logic for selecting the Group Replication query more robust and future-proof for versions 8.0.0 and above.
• Comment Clarity: The comment on line 696 was updated from // MySQL-8: to // From MySQL-8:. This is a minor stylistic improvement that slightly enhances readability. As per the review settings, a formal review comment was not added for this low-severity improvement.

Merge Readiness

The changes in this pull request are well-implemented and improve the robustness of the MySQL version checking logic. I found no critical or high-severity issues. The code appears to be in good shape and ready for merging. As an AI, I am not authorized to approve pull requests, so please ensure it is reviewed and approved by other maintainers before merging.