fix bvt/purge_log (#1.1-dev)

[YANGGMM]

changes:

1. get the newest collecttime as target time to check result.

Approved by: @heni02

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #15455

What this PR does / why we need it:

fix bvt/purge_log

[matrix-meow]

@YANGGMM Thanks for your contributions!

Pull Request Review:

Title:

The title of the pull request is clear and concise, indicating that it is fixing an issue related to bvt/purge_log.

Body:

The body of the pull request provides a brief overview of the changes made, mentions the issue number that is being addressed (issue #15455), and specifies the type of PR (BUG). It also includes the approval information. The body is informative and to the point.

Changes:

1. In the func_purge_log.result file:
   • Line 29: Changed the interval from 1 minute to 5 minutes in the SQL query.
2. In the func_purge_log.sql file:
   • Line 25: Changed the interval from 1 minute to 5 minutes in the SQL query.
3. In the system_table_cases.sql file:
   • Updated comments and queries related to span_info table.

Feedback and Suggestions for Improvement:

1. SQL Injection Risk:

   • The use of IFNULL in the SQL query to handle potential NULL values is good practice. However, it's important to ensure that the input values are properly sanitized to prevent SQL injection attacks. Consider using parameterized queries or input validation to mitigate this risk.

2. Magic Numbers:

   • The interval values (1 day, 5 minutes) are hardcoded in multiple places. It would be beneficial to define these values as constants or variables at the beginning of the file to improve code readability and maintainability.

3. Comment Clarity:

   • The comments in the system_table_cases.sql file mention issues like "11,947" without clear context. It's recommended to provide more descriptive comments to explain the purpose of the queries and their relation to specific issues for better understanding.

4. Consistency in Comments:

   • Ensure consistency in commenting style throughout the codebase. For example, use a consistent format for mentioning issues (e.g., -- issue 11,947 vs. -- issue 11,947 end).

5. Optimization:

   • Consider consolidating repetitive queries or code blocks to reduce redundancy and improve code maintainability. For instance, the similar COUNT queries in system_table_cases.sql could be combined into a single query with different conditions.

6. Testing:

   • Ensure that appropriate testing is conducted to validate the changes made in the PR, especially considering the impact on the purge_log functionality.

7. Documentation:

   • Update any relevant documentation or README files to reflect the changes made in this PR, especially if it affects the usage or behavior of the purge_log functionality.

By addressing these points, the code quality, security, and maintainability of the bvt/purge_log functionality can be enhanced.