1 files changed, 31 insertions, 0 deletions
diff --git a/db/migrate/20201202155913_add_primary_key_to_merge_request_context_commit_diff_files.rb b/db/migrate/20201202155913_add_primary_key_to_merge_request_context_commit_diff_files.rb
new file mode 100644
index 00000000000..90c7b2731c8
--- /dev/null
+++ b/db/migrate/20201202155913_add_primary_key_to_merge_request_context_commit_diff_files.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class AddPrimaryKeyToMergeRequestContextCommitDiffFiles < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    execute(<<~SQL)
+      DELETE FROM merge_request_context_commit_diff_files
+      WHERE merge_request_context_commit_id IS NULL;
+
+      DELETE FROM merge_request_context_commit_diff_files df1
+      USING merge_request_context_commit_diff_files df2
+      WHERE df1.ctid < df2.ctid
+        AND df1.merge_request_context_commit_id = df2.merge_request_context_commit_id
+        AND df1.relative_order = df2.relative_order;
+
+      ALTER TABLE merge_request_context_commit_diff_files
+      ADD CONSTRAINT merge_request_context_commit_diff_files_pkey PRIMARY KEY (merge_request_context_commit_id, relative_order);
+    SQL
+  end
+
+  def down
+    execute(<<~SQL)
+      ALTER TABLE merge_request_context_commit_diff_files
+      DROP CONSTRAINT merge_request_context_commit_diff_files_pkey,
+      ALTER COLUMN merge_request_context_commit_id DROP NOT NULL
+    SQL
+  end
+end