1 files changed, 46 insertions, 0 deletions
diff --git a/db/post_migrate/20201014142521_schedule_sync_blocking_issues_count.rb b/db/post_migrate/20201014142521_schedule_sync_blocking_issues_count.rb
new file mode 100644
index 00000000000..61b2b2aaad5
--- /dev/null
+++ b/db/post_migrate/20201014142521_schedule_sync_blocking_issues_count.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require 'set'
+
+class ScheduleSyncBlockingIssuesCount < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  BATCH_SIZE = 50
+  DELAY_INTERVAL = 120.seconds.to_i
+  MIGRATION = 'SyncBlockingIssuesCount'.freeze
+
+  disable_ddl_transaction!
+
+  class TmpIssueLink < ActiveRecord::Base
+    self.table_name = 'issue_links'
+
+    include EachBatch
+  end
+
+  def up
+    return unless Gitlab.ee?
+
+    issue_link_ids = SortedSet.new
+
+    TmpIssueLink.distinct.select(:source_id).where(link_type: 1).each_batch(of: 1000, column: :source_id) do |query|
+      issue_link_ids.merge(query.pluck(:source_id))
+    end
+
+    TmpIssueLink.distinct.select(:target_id).where(link_type: 2).each_batch(of: 1000, column: :target_id) do |query|
+      issue_link_ids.merge(query.pluck(:target_id))
+    end
+
+    issue_link_ids.each_slice(BATCH_SIZE).with_index do |items, index|
+      start_id, *, end_id = items
+
+      arguments = [start_id, end_id]
+
+      final_delay = DELAY_INTERVAL * (index + 1)
+      migrate_in(final_delay, MIGRATION, arguments)
+    end
+  end
+
+  def down
+    # NO OP
+  end
+end