1 files changed, 33 insertions, 0 deletions
diff --git a/db/migrate/20170928100231_add_composite_index_on_merge_requests_merge_commit_sha.rb b/db/migrate/20170928100231_add_composite_index_on_merge_requests_merge_commit_sha.rb
new file mode 100644
index 00000000000..9f02daf04c1
--- /dev/null
+++ b/db/migrate/20170928100231_add_composite_index_on_merge_requests_merge_commit_sha.rb
@@ -0,0 +1,33 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddCompositeIndexOnMergeRequestsMergeCommitSha < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  # The default index name is too long for PostgreSQL and would thus be
+  # truncated.
+  INDEX_NAME = 'index_merge_requests_on_tp_id_and_merge_commit_sha_and_id'
+
+  COLUMNS = [:target_project_id, :merge_commit_sha, :id]
+
+  disable_ddl_transaction!
+
+  def up
+    return if index_is_present?
+
+    add_concurrent_index(:merge_requests, COLUMNS, name: INDEX_NAME)
+  end
+
+  def down
+    return unless index_is_present?
+
+    remove_concurrent_index(:merge_requests, COLUMNS, name: INDEX_NAME)
+  end
+
+  def index_is_present?
+    index_exists?(:merge_requests, COLUMNS, name: INDEX_NAME)
+  end
+end