Add indexes and change SQL for expired artifacts to deal with artifacts migration efficiently

Artifacts are in the middle of being migrated from ci_builds to
ci_job_artifacts. The expiration date is currently visible in both of
these tables and the test for whether an expired artifact is present
for a job is complex as it requires checking both the of the tables.

Add two new indexes, one on ci_builds.artifacts_expire_at and one on
ci_job_artifacts.expire_at to enable finding expired artifacts
efficiently.

And until the migration is finished, replace the SQL for finding
expired and non-expired artifacts with a hand-crafted UNION ALL based
query instead of using OR. This overcomes a database optimizer
limitation that prevents it from using these indexes.

When the migration is finished the next version should remove this
query and replace it with a much simpler query on just
ci_job_artifacts. See
https://gitlab.com/gitlab-org/gitlab-ce/issues/42561 for followup.

1 files changed, 2 insertions, 2 deletions

diff --git a/spec/factories/ci/builds.rb b/spec/factories/ci/builds.rb
index 6ba599cdf83..f6ba3a581ca 100644
--- a/spec/factories/ci/builds.rb
+++ b/spec/factories/ci/builds.rb
@@ -180,8 +180,8 @@ FactoryBot.define do
 
     trait :artifacts do
       after(:create) do |build|
-        create(:ci_job_artifact, :archive, job: build)
-        create(:ci_job_artifact, :metadata, job: build)
+        create(:ci_job_artifact, :archive, job: build, expire_at: build.artifacts_expire_at)
+        create(:ci_job_artifact, :metadata, job: build, expire_at: build.artifacts_expire_at)
         build.reload
       end
     end