Making GitLab Faster

This post details performance improvements in GitLab 8.5, specifically addressing two key areas: optimizing the fetching of issues closed by a merge request and improving the performance of retrieving last update times for events. For issue fetching, the approach was changed from iterating through each commit to concatenating all commit messages and the merge request description into a single string for a more efficient database query. This reduced latency from seconds to under 15 milliseconds. For event feeds, the SQL query for retrieving events based on user project access was optimized to improve performance.