1 files changed, 36 insertions, 0 deletions
diff --git a/db/migrate/20171121135738_clean_up_from_merge_request_diffs_and_commits.rb b/db/migrate/20171121135738_clean_up_from_merge_request_diffs_and_commits.rb
new file mode 100644
index 00000000000..30cf08b29fc
--- /dev/null
+++ b/db/migrate/20171121135738_clean_up_from_merge_request_diffs_and_commits.rb
@@ -0,0 +1,36 @@
+class CleanUpFromMergeRequestDiffsAndCommits < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  class MergeRequestDiff < ActiveRecord::Base
+    self.table_name = 'merge_request_diffs'
+
+    include ::EachBatch
+  end
+
+  disable_ddl_transaction!
+
+  def up
+    Gitlab::BackgroundMigration.steal('DeserializeMergeRequestDiffsAndCommits')
+
+    # The literal '--- []\n' value is created by the import process and treated
+    # as null by the application, so we can ignore those - even if we were
+    # migrating, it wouldn't create any rows.
+    literal_prefix = Gitlab::Database.postgresql? ? 'E' : ''
+    non_empty = "
+      (st_commits IS NOT NULL AND st_commits != #{literal_prefix}'--- []\n')
+      OR
+      (st_diffs IS NOT NULL AND st_diffs != #{literal_prefix}'--- []\n')
+    ".squish
+
+    MergeRequestDiff.where(non_empty).each_batch(of: 500) do |relation, index|
+      range = relation.pluck('MIN(id)', 'MAX(id)').first
+
+      Gitlab::BackgroundMigration::DeserializeMergeRequestDiffsAndCommits.new.perform(*range)
+    end
+  end
+
+  def down
+  end
+end