Meta: Milestone Performance

Description

Milestone page has a performance problem (slow) (meta: gitlab-foss#23213 (moved)).

TODO

• [Project/Group/Dashboard] Drop GFM support gitlab-foss#34289 (closed) gitlab-foss!12444 (merged)
• [Project] Use eager load to avoid N+1 problem gitlab-foss#34736 (closed) gitlab-foss!12670 (merged)
• [Group/Dashboard] Eager load to avoid N+1 queries when there are labels from multiple projects in a milestone gitlab-foss!10403

Links / references

• A milestone with 200 issues, 500 merge requests, 50 participants and 100 labels takes 6 sec for the first byte and 13 sec to complete
  • before 9.3.0-rcXXXX
    • cf. https://tools.pingdom.com/#!/bAW3FE/https://gitlab.com/gitlab-org/gitlab-ce/milestones/39 (X-Runtime: 5.313123)
    • cf. https://www.webpagetest.org/result/170616_WB_27aee42fb5b1bb8ee32770e4e372a049/
  • after 9.4.0-rc3-ee (applying gitlab-foss!12444 (merged), gitlab-foss!12670 (merged))
    • https://tools.pingdom.com/#!/dZX8f1/https://gitlab.com/gitlab-org/gitlab-ce/milestones/39 (X-Runtime: 2.828152) (47% faster before/after two patches)
• A milestone with 1 issue, 0 merge requests, 1 participant and 0 labels takes 0.7-1 sec for the first byte and 3 sec to complete
  • before

    • cf. https://tools.pingdom.com/#!/ekEvpk/https://gitlab.com/tnir/tnir-gitlab-test-general/milestones/4 (0.591097)

    • cf. https://www.webpagetest.org/result/170619_7C_1ER5/

  • after 9.4.0-rc3-ee (applying gitlab-foss!12444 (merged), gitlab-foss!12670 (merged))
    • 0.218086 (63% faster before/after two patches)