Merge branch 'issue_27168_2' into 'master'

Preloads head pipeline for each merge request

Closes #27168

See merge request !10064

3 files changed, 34 insertions, 1 deletions

diff --git a/db/migrate/20170507205316_add_head_pipeline_id_to_merge_requests.rb b/db/migrate/20170507205316_add_head_pipeline_id_to_merge_requests.rb
new file mode 100644
index 00000000000..8fc6e380a77
--- /dev/null
+++ b/db/migrate/20170507205316_add_head_pipeline_id_to_merge_requests.rb
@@ -0,0 +1,7 @@
+class AddHeadPipelineIdToMergeRequests < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    add_column :merge_requests, :head_pipeline_id, :integer
+  end
+end
diff --git a/db/post_migrate/20170508170547_add_head_pipeline_for_each_merge_request.rb b/db/post_migrate/20170508170547_add_head_pipeline_for_each_merge_request.rb
new file mode 100644
index 00000000000..bc3850c0c23
--- /dev/null
+++ b/db/post_migrate/20170508170547_add_head_pipeline_for_each_merge_request.rb
@@ -0,0 +1,25 @@
+class AddHeadPipelineForEachMergeRequest < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    disable_statement_timeout
+
+    pipelines = Arel::Table.new(:ci_pipelines)
+    merge_requests = Arel::Table.new(:merge_requests)
+
+    head_id = pipelines.
+      project(Arel::Nodes::NamedFunction.new('max', [pipelines[:id]])).
+      from(pipelines).
+      where(pipelines[:ref].eq(merge_requests[:source_branch])).
+      where(pipelines[:project_id].eq(merge_requests[:source_project_id]))
+
+    sub_query = Arel::Nodes::SqlLiteral.new(Arel::Nodes::Grouping.new(head_id).to_sql)
+
+    update_column_in_batches(:merge_requests, :head_pipeline_id, sub_query)
+  end
+
+  def down
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 722e776c27d..b91b3e6e977 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170506185517) do
+ActiveRecord::Schema.define(version: 20170508170547) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -690,6 +690,7 @@ ActiveRecord::Schema.define(version: 20170506185517) do
     t.integer "cached_markdown_version"
     t.datetime "last_edited_at"
     t.integer "last_edited_by_id"
+    t.integer "head_pipeline_id"
   end
 
   add_index "merge_requests", ["assignee_id"], name: "index_merge_requests_on_assignee_id", using: :btree