Development: Speedup loading of active courses

[Strohgelaender]

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.
• This is a small issue that I tested locally and was confirmed by another developer on a test server.
• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

Server

• Important: I implemented the changes with a very good performance and prevented too many (unnecessary) and too complex database calls.
• I strictly followed the principle of data economy for all database calls.
• I strictly followed the server coding and design guidelines.

Motivation and Context

While reviewing PR #9727 I spotted a filter call that could be moved into a database query to improve performance.

Description

We now directly filter out inactive courses at the database level to avoid loading to many objects.

Steps for Testing

Navigate to Aretmis -> Course management and check that the currently active courses are diplayed correctly.

Testserver States

Note

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Review Progress

Performance Review

• I (as a reviewer) confirm that the client changes (in particular related to REST calls and UI responsiveness) are implemented with a very good performance even for very large courses with more than 2000 students.
• I (as a reviewer) confirm that the server changes (in particular related to database calls) are implemented with a very good performance even for very large courses with more than 2000 students.

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Performance Tests

• Test 1
• Test 2

Summary by CodeRabbit

• New Features

  • Introduced a new method to retrieve active courses for users with tutor roles, enhancing course management.

• Improvements

  • Streamlined the retrieval process for courses, improving efficiency and reducing complexity in the code.

• Bug Fixes

  • Updated method naming conventions for clarity and consistency.

[coderabbitai]

Walkthrough

The changes involve updates to the CourseRepository and CourseResource classes. In CourseRepository, a method has been renamed and a new method added to enhance course retrieval based on user roles and course activity status. In CourseResource, the getCoursesForTutors method has been refactored to improve efficiency by directly querying for active courses, eliminating unnecessary intermediate variables, while maintaining its original functionality.

Changes

File Path	Change Summary
src/main/java/de/tum/cit/aet/artemis/core/repository/CourseRepository.java	- Renamed method: findCoursesForAtLeastTutorWithGroups → findAllCoursesForAtLeastTutorWithGroups - Added method: findActiveCoursesForAtLeastTutorWithGroups to retrieve active courses based on user group membership.
src/main/java/de/tum/cit/aet/artemis/core/web/CourseResource.java	- Refactored getCoursesForTutors method to directly query for active courses, improving efficiency and reducing cyclomatic complexity. No changes to method signatures.

Suggested labels

ready for review, performance, small

Suggested reviewers

• krusche
• florian-glombik
• MaximilianAnzinger

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[coderabbitai]

Actionable comments posted: 0

🧹 Outside diff range and nitpick comments (1)

src/main/java/de/tum/cit/aet/artemis/core/web/CourseResource.java (1)

451-454: Great optimization: Moving filtering to the database level!

The refactoring improves performance by leveraging database-level filtering instead of in-memory filtering. This is particularly beneficial when dealing with large datasets.

Consider adding a comment explaining the performance optimization for future maintainers:

    if (onlyActive) {
        // only include courses that have NOT been finished
        final var now = ZonedDateTime.now();
+       // Filtering is done at database level for better performance
        return courseRepository.findActiveCoursesForAtLeastTutorWithGroups(user.getGroups(), authCheckService.isAdmin(user), now);
    }

📜 Review details

Configuration used: .coderabbit.yaml
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between 054476c and bf6296a.

📒 Files selected for processing (2)

• src/main/java/de/tum/cit/aet/artemis/core/repository/CourseRepository.java (1 hunks)
• src/main/java/de/tum/cit/aet/artemis/core/web/CourseResource.java (1 hunks)

🧰 Additional context used

📓 Path-based instructions (2)

src/main/java/de/tum/cit/aet/artemis/core/repository/CourseRepository.java (1)

Pattern src/main/java/**/*.java: naming:CamelCase; principles:{single_responsibility,small_methods,no_duplication}; db:{perf_queries,datetime_not_timestamp}; rest:{stateless,singleton,delegate_logic,http_only,minimal_dtos}; dtos:{java_records,no_entities,min_data,single_resp}; di:constructor_injection; kiss:simple_code; file_handling:os_indep_paths; practices:{least_access,avoid_transactions,code_reuse,static_member_ref,prefer_primitives}; sql:{param_annotation,uppercase,avoid_subqueries};java:avoid_star_imports

src/main/java/de/tum/cit/aet/artemis/core/web/CourseResource.java (1)

Pattern src/main/java/**/*.java: naming:CamelCase; principles:{single_responsibility,small_methods,no_duplication}; db:{perf_queries,datetime_not_timestamp}; rest:{stateless,singleton,delegate_logic,http_only,minimal_dtos}; dtos:{java_records,no_entities,min_data,single_resp}; di:constructor_injection; kiss:simple_code; file_handling:os_indep_paths; practices:{least_access,avoid_transactions,code_reuse,static_member_ref,prefer_primitives}; sql:{param_annotation,uppercase,avoid_subqueries};java:avoid_star_imports

🔇 Additional comments (2)

src/main/java/de/tum/cit/aet/artemis/core/repository/CourseRepository.java (2)

583-584: LGTM! Method rename improves clarity.

The rename from findCoursesForAtLeastTutorWithGroups to findAllCoursesForAtLeastTutorWithGroups better describes the method's behavior by explicitly indicating it returns all courses.

---

585-594: LGTM! Efficient implementation of active courses filtering.

The new method efficiently implements the PR's performance objective by:

1. Filtering active courses directly at the database level
2. Using proper parameter binding for the timestamp
3. Following the repository's consistent pattern for handling course dates

This implementation prevents unnecessary loading of inactive courses, reducing both database load and memory usage.

[Longppham]

I tested this PR on TS4 as a student (Was not specified which to choose?) Following the instructions, I went to artemis and then clicked on course management which lead then to the screenshot I attached here. When I check the box show only active courses, nothing changes.
Works like described.

[Strohgelaender]

In the current courses, it says 76 but after clicking course management, only 1 Course is shown.

On the front page all courses (where you are at least student) are shown, on the course management page you only see courses where you are at least tutor. So that's a correct behaviour.

[Longppham]

In the current courses, it says 76 but after clicking course management, only 1 Course is shown.

On the front page all courses (where you are at least student) are shown, on the course management page you only see courses where you are at least tutor. So that's a correct behaviour.

Perfect! I was not sure how it worked for my account! Should i edit my old comment?

[HawKhiem]

Tested on TS1 with both tutor and instructor test accounts. All active courses were displayed correctly

[sawys777]

Tested on TS1, everything worked as expected.

[Cathy0123456789]

Tested on TS1. Active courses are displayed correctly

[flbrgit]

Tested on TS4. Everything works as expected

[JerroyTan]

[Tested on TS3]
Active courses displayed correctly without problem.