MergeRequest Notes API Slow for Large Notes
Summary
MergeRequest Notes API poor performance on large notes, when compared to UI performance.
This was discovered when wondering why one of our merge-request check bots was timing out on certain merge requests. The use case of what triggers this is that a branch was created as a hotfix into a previous release, but then determined not to be a hotfix, and rebased and retargeted into master (in that specific order of actions).
Steps to reproduce
Create a new
branch from target
, add a couple commits to new
. Create an MR from new
to target
. Rebase new
such that it has a few (2+) thousand commits that aren't in target
. Force push new
.
Example Project
Example MR
Example MR API call
What is the current bug behavior?
The API request can take tens of seconds, whereas the UI seems to load the same data "quickly" (less than three seconds).
What is the expected correct behavior?
API call should be no slower than the UI call.
Output of checks
This bug happens on GitLab.com, as well as on our self-hosted instance.