fix: slow conversation list queries [WPB-11808]

[saleniuk]

WPB-11808 [Android] app stalls when fetching a page of conversations from the local DB

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PR Submission Checklist for internal contributors

• The PR Title

  • conforms to the style of semantic commits messages¹ supported in Wire's Github Workflow²
  • contains a reference JIRA issue number like SQPIT-764
  • answers the question: If merged, this PR will: ... ³

• The PR Description

  • is free of optional paragraphs and you have filled the relevant parts to the best of your ability

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What's new in this PR?

Issues

Paginated conversation list queries are very slow when there are many conversations and/or messages in the database.

Causes (Optional)

I noticed that the biggest impact on the execution time was the nested query to get last message id for the conversation.
Also, every time the draft message is upserted, even with the same value, then conversation list query is notified and reloads.

Solutions

Replaced nested query with just using MAX - we already make GROUP BY so when using MAX(LastMessage.creation_date) it will left join the message with largest creation_date which is the last one, no need to make a nested query to get that.
For draft messages, do not make update query when nothing changed and make it inside the transaction to rollback it if nothing is changed - thanks to that no other query will be notified about this update unnecessarily.

Testing

Test Coverage (Optional)

• I have added automated test to this contribution

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PR Post Submission Checklist for internal contributors (Optional)

• Wire's Github Workflow has automatically linked the PR to a JIRA issue

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PR Post Merge Checklist for internal contributors

• If any soft of configuration variable was introduced by this PR, it has been added to the relevant documents and the CI jobs have been updated.

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References

1. https://sparkbox.com/foundry/semantic_commit_messages
2. https://github.com/wireapp/.github#usage
3. E.g. feat(conversation-list): Sort conversations by most emojis in the title #SQPIT-764.

[github-actions]

Test Results

3 253 tests  +2   3 147 ✅ +2   4m 32s ⏱️ +9s
  555 suites ±0     106 💤 ±0 
  555 files   ±0       0 ❌ ±0 

Results for commit 9b554af. ± Comparison against base commit 9a517ea.

♻️ This comment has been updated with latest results.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.

Project coverage is 52.58%. Comparing base (9a517ea) to head (9b554af).

Files with missing lines	Patch %	Lines
...rsistence/dao/message/draft/MessageDraftDAOImpl.kt	90.90%	1 Missing ⚠️

Additional details and impacted files

@@                  Coverage Diff                  @@
##           release/candidate    #3080      +/-   ##
=====================================================
+ Coverage              52.55%   52.58%   +0.02%     
=====================================================
  Files                   1318     1318              
  Lines                  51445    51458      +13     
  Branches                4772     4774       +2     
=====================================================
+ Hits                   27039    27060      +21     
+ Misses                 22445    22437       -8     
  Partials                1961     1961              

Files with missing lines	Coverage Δ
...rsistence/dao/message/draft/MessageDraftDAOImpl.kt	92.68% <90.90%> (+9.34%)	⬆️

... and 3 files with indirect coverage changes

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[datadog-wireapp]

Datadog Report

Branch report: fix/slow-conversation-list-queries
Commit report: a52d8d3
Test service: kalium-jvm

✅ 0 Failed, 3147 Passed, 106 Skipped, 30.79s Total Time

[sonarcloud]

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 SonarCloud