Merge branch 'es_partial_indexing' into 'master'

Elastic: partial indexing on push

https://gitlab.com/gitlab-org/gitlab-ee/issues/220

See merge request !142

CHANGELOG-EE

@@ -10,6 +10,9 @@ v 8.4.2 (unreleased)
 v 8.4.2
   - Rake task gitlab:elastic:index_repositories handles errors and shows progress
 
+v 8.4.2
+  - Partial indexing of repo on push (indexing changes only).
+
 v 8.4.1
   - No EE-specific changes
 

app/services/git_push_service.rb

@@ -66,8 +66,8 @@ class GitPushService
     project.execute_services(@push_data.dup, :push_hooks)
 
     if Gitlab.config.elasticsearch.enabled
-      project.repository.index_commits
-      project.repository.index_blobs
+      project.repository.index_commits(from_rev: oldrev, to_rev: newrev)
+      project.repository.index_blobs(from_rev: oldrev, to_rev: oldrev)
     end
 
     CreateCommitBuildsService.new.execute(project, @user, @push_data, mirror_update: mirror_update)