Merge branch '15094-throttling-pushes_since_gc' into 'master'

Throttle the update of `project.pushes_since_gc` to 1 minute

## What does this MR do?

Throttle the update of `project.pushes_since_gc` to alleviate DB load

## What are the relevant issue numbers?

Relates to #15094

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- ~~[ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~[ ] API support added~~
- Tests
  - ~~[ ] Added for this feature/bug~~
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !5083

CHANGELOG

@@ -26,6 +26,7 @@ v 8.10.0 (unreleased)
   - Add "Enabled Git access protocols" to Application Settings
   - Fix user creation with stronger minimum password requirements !4054 (nathan-pmt)
   - PipelinesFinder uses git cache data
+  - Throttle the update of `project.pushes_since_gc` to 1 minute.
   - Check for conflicts with existing Project's wiki path when creating a new project.
   - Don't instantiate a git tree on Projects show default view
   - Bump Rinku to 2.0.0

app/services/projects/housekeeping_service.rb

@@ -27,7 +27,7 @@ module Projects
       GitlabShellOneShotWorker.perform_async(:gc, @project.repository_storage_path, @project.path_with_namespace)
     ensure
       Gitlab::Metrics.measure(:reset_pushes_since_gc) do
-        @project.update_column(:pushes_since_gc, 0)
+        update_pushes_since_gc(0)
       end
     end
 
@@ -37,12 +37,18 @@ module Projects
 
     def increment!
       Gitlab::Metrics.measure(:increment_pushes_since_gc) do
-        @project.increment!(:pushes_since_gc)
+        update_pushes_since_gc(@project.pushes_since_gc + 1)
       end
     end
 
     private
 
+    def update_pushes_since_gc(new_value)
+      if Gitlab::ExclusiveLease.new("project_housekeeping:update_pushes_since_gc:#{project.id}", timeout: 60).try_obtain
+        @project.update_column(:pushes_since_gc, new_value)
+      end
+    end
+
     def try_obtain_lease
       Gitlab::Metrics.measure(:obtain_housekeeping_lease) do
         lease = ::Gitlab::ExclusiveLease.new("project_housekeeping:#{@project.id}", timeout: LEASE_TIMEOUT)