1 files changed, 34 insertions, 0 deletions
diff --git a/db/post_migrate/20200406102120_backfill_deployment_clusters_from_deployments.rb b/db/post_migrate/20200406102120_backfill_deployment_clusters_from_deployments.rb
new file mode 100644
index 00000000000..2db270d303c
--- /dev/null
+++ b/db/post_migrate/20200406102120_backfill_deployment_clusters_from_deployments.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class BackfillDeploymentClustersFromDeployments < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  MIGRATION = 'BackfillDeploymentClustersFromDeployments'
+  DELAY_INTERVAL = 2.minutes
+  BATCH_SIZE = 10_000
+
+  disable_ddl_transaction!
+
+  class Deployment < ActiveRecord::Base
+    include EachBatch
+
+    default_scope { where('cluster_id IS NOT NULL') }
+
+    self.table_name = 'deployments'
+  end
+
+  def up
+    say "Scheduling `#{MIGRATION}` jobs"
+
+    queue_background_migration_jobs_by_range_at_intervals(Deployment, MIGRATION, DELAY_INTERVAL, batch_size: BATCH_SIZE)
+  end
+
+  def down
+    # NOOP
+  end
+end