What does this MR do?
This MR is to skip the redundant persistent ref existence check. This pressurizes Gitaly nodes and if timeout happens, it could end up fetching all refspecs in runner. The assumption was described by @stanhu at gitlab-com/gl-infra/production#2143 (comment 343690877)
Ok, maybe this is what happened based on https://log.gprd.gitlab.net/goto/15e8e5a9084502a3b17113fa0e0c1e60:
- The ref did, in fact, exist. It seems like there are many chances to create the ref since every build attempts to do so.
- However, the
RefExistscall timed out.
- As a result, https://gitlab.com/gitlab-org/gitlab/blob/2bfe8f06724470576e408f3cc282a30f0c271880/app/models/ci/persistent_ref.rb#L18-19 returned
false, and the CI pipeline got an empty refspec.
I still wonder why so many RPCs were stalling out, but perhaps we should cache the existence of this ref?
Does this MR meet the acceptance criteria?
Documentation (if required)
Code review guidelines
Merge request performance guidelines
Separation of EE specific content
Availability and Testing
Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
Tested in all supported browsers
Informed Infrastructure department of a default or new setting change, if applicable per definition of done
If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:
Label as security and @ mention
The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
Security reports checked/validated by a reviewer from the AppSec team