Development: Avoid database queries with pagination and left join fetch

[krusche]

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.
• I chose a title conforming to the naming conventions for pull requests.

Server

• I strictly followed the server coding and design guidelines.
• I documented the Java code using JavaDoc style.

Motivation and Context

Pagination combined with fetching ("left join fetch") leads to potential performance issues (see https://vladmihalcea.com/hibernate-query-fail-on-pagination-over-collection-fetch) and to ugly warnings in the logs HHH90003004: firstResult/maxResults specified with collection fetch; applying in memory

Description

• We already added TODOs into the code and now activated the setting hibernate.query.fail_on_pagination_over_collection_fetch: true in the src and test code to find all places that combine pagination with left join fetch.
• To solve the issue, we need to split the query into two parts:
  1. Find the ids without any additional fetching (potentially including joins for conditions in the where clause)
  2. Use the ids to load the actual objects with additional fetching of related objects
• In case of sorting (order by), we might need to make sure that the custom order is maintained in the second query of afterwards in Java.

A good example of this (based on the Specification API) can be found in the changes of #5257.

Steps for Testing

The database queries could influence these parts of the application:

1. Test programming exercises and everything around them.
2. Test Iris.
3. Test conversations in a course.
4. Exam mode testing.
   You can test one of them.
   I created a course with all types of exercises on ts5 in my test course, and you can take an exam there as well.

Also, you are welcome to test other features that are not mentioned in this list.

Testserver States

Note

These badges show the state of the test servers.
Green = Currently available, Red = Currently locked

Review Progress

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Exam Mode Test

• Test 1
• Test 2

Test Coverage

Server

Class/File	Line Coverage	Confirmation (assert/expect)
BuildJobRepository.java	0%	✅ ❌
PersistenceAuditEventRepository.java	87%	✅ ❌
ProgrammingSubmissionRepository.java	77%	✅ ❌
ResultRepository.java	94%	✅ ❌
StudentParticipationRepository.java	93%	✅ ❌
UserRepository.java	86%	✅ ❌
RepositoryImpl.java	66%	✅ ❌
CoverageReportRepository.java	82%	✅ ❌
IrisCourseChatSessionRepository.java	0%	✅ ❌
IrisExerciseChatSessionRepository.java	80%	✅ ❌
IrisMessageRepository.java	0%	✅ ❌
PlagiarismResultRepository.java	100%	✅
AuditEventService.java	100%	✅
SubmissionService.java	90%	✅ ❌
SharedQueueManagementService.java	93%	✅ ❌
Lti13Service.java	88%	✅ ❌
ProgrammingExerciseGitDiffReportService.java	81%	✅ ❌
TestwiseCoverageService.java	69%	✅ ❌
ConversationService.java	93%	✅ ❌
ProgrammingExerciseGradingService.java	96%	✅ ❌
ProgrammingSubmissionService.java	87%	✅ ❌
CourseResource.java	89%	✅ ❌
ModelingExerciseResource.java	96%	✅ ❌
ParticipationResource.java	87%	✅ ❌
TextExerciseResource.java	96%	✅ ❌
ConversationResource.java	92%	✅ ❌
ProgrammingExercisePlagiarismResource.java	86%	✅ ❌

Client coverage was not changed.

Summary by CodeRabbit

• Bug Fixes

  • Enhanced query performance across various repositories for more efficient data retrieval.

• New Features

  • Introduced methods to search and filter users by login or name within groups, courses, and conversations.
  • Added new methods to retrieve detailed information on programming submissions, results, and coverage reports.
  • Enhanced message retrieval capabilities with new methods in the IrisMessage repository, improving error handling and efficiency.

• Refactor

  • Refined existing methods in repositories for optimized query execution and improved readability.
  • Updated repository method calls to enhance specificity and performance.

• Documentation

  • Improved comments and Javadoc annotations for better clarity and understanding.

• Chores

  • Updated repository method signatures and imports for better code maintainability and performance.

[coderabbitai]

Walkthrough

Recent updates across multiple repository files significantly enhance data retrieval efficiency and optimize query performance for various entities such as programming submissions, results, and users. New methods have been introduced, and existing ones have been refactored for improved functionality and clarity. These changes collectively aim to streamline access to data and boost overall system performance, particularly within the context of programming exercises and user management.

Changes

File Path	Change Summary
src/main/java/de/tum/in/www1/artemis/repository/.../ProgrammingSubmissionRepository.java	Enhanced querying capabilities for programming submissions with new methods to fetch structured data and optimized retrieval based on participation ID and submission date.
src/main/java/de/tum/in/www1/artemis/repository/.../ResultRepository.java	Introduced methods for improved result retrieval, including feedback and test cases integration, while optimizing existing queries for better performance and readability.
src/main/java/de/tum/in/www1/artemis/repository/.../StudentParticipationRepository.java	Added new and default methods to enhance effective data retrieval based on exercise ID and student name, improving overall functionality and performance.
src/main/java/de/tum/in/www1/artemis/repository/.../UserRepository.java	Introduced extensive new search methods that enhance flexibility and performance for user-related queries across various contexts.
src/main/java/de/tum/in/www1/artemis/repository/.../CoverageReportRepository.java	Improved data handling in coverage reports with new methods and optimized query processes, enhancing retrieval efficiency.
src/main/java/de/tum/in/www1/artemis/repository/.../IrisMessageRepository.java	Added error handling methods and improved message retrieval, ensuring better management of message entities and enhancing performance.

Sequence Diagram(s)

Sequence Diagram for Programming Submission Result Retrieval

sequenceDiagram
    participant Student as Student
    participant CourseOverview as CourseOverview
    participant ProgrammingSubmissionRepository as ProgrammingSubmissionRepository

    Student->>CourseOverview: request latest submission results
    CourseOverview->>ProgrammingSubmissionRepository: findFirstIdByParticipationIdOrderBySubmissionDateDesc(participationId, Pageable)
    ProgrammingSubmissionRepository-->>CourseOverview: List<ProgrammingSubmissionIdAndSubmissionDateDTO>
    CourseOverview-->>Student: display latest submission results

Loading

Possibly Related Issues

• Programing exercise: Student does not see the results from the latest submission in the overview #9086: Changes in the ProgrammingSubmissionRepository address issues with displaying the latest submission results, potentially resolving the Query did not return a unique result error by ensuring more deterministic retrieval of programming submissions.

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[coderabbitai]

Actionable comments posted: 1

[julian-christl]

code

[JohannesStoehr]

Code

[EneaGore]

re-approve

[SimonEntholzer]

Tested on TS6 and didn't encounter any issues

[MaximilianAnzinger]

Love the extensive usage of derived queries 👍
LGTM