1 files changed, 27 insertions, 0 deletions
diff --git a/db/migrate/20180524132016_merge_requests_target_id_iid_state_partial_index.rb b/db/migrate/20180524132016_merge_requests_target_id_iid_state_partial_index.rb
new file mode 100644
index 00000000000..cee576b91c8
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+++ b/db/migrate/20180524132016_merge_requests_target_id_iid_state_partial_index.rb
@@ -0,0 +1,27 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class MergeRequestsTargetIdIidStatePartialIndex < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  INDEX_NAME = 'index_merge_requests_on_target_project_id_and_iid_opened'
+
+  disable_ddl_transaction!
+
+  def up
+    # On GitLab.com this index will take up roughly 5 MB of space.
+    add_concurrent_index(
+      :merge_requests,
+      [:target_project_id, :iid],
+      where: "state = 'opened'",
+      name: INDEX_NAME
+    )
+  end
+
+  def down
+    remove_concurrent_index_by_name(:merge_requests, INDEX_NAME)
+  end
+end