1 files changed, 37 insertions, 0 deletions
diff --git a/db/post_migrate/20210730104800_schedule_extract_project_topics_into_separate_table.rb b/db/post_migrate/20210730104800_schedule_extract_project_topics_into_separate_table.rb
new file mode 100644
index 00000000000..3102561a129
--- /dev/null
+++ b/db/post_migrate/20210730104800_schedule_extract_project_topics_into_separate_table.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+class ScheduleExtractProjectTopicsIntoSeparateTable < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 1_000
+  DELAY_INTERVAL = 2.minutes
+  MIGRATION = 'ExtractProjectTopicsIntoSeparateTable'
+  INDEX_NAME = 'tmp_index_taggings_on_id_where_taggable_type_project'
+  INDEX_CONDITION = "taggable_type = 'Project'"
+
+  disable_ddl_transaction!
+
+  class Tagging < ActiveRecord::Base
+    include ::EachBatch
+
+    self.table_name = 'taggings'
+  end
+
+  def up
+    # this index is used in 20210730104800_schedule_extract_project_topics_into_separate_table
+    add_concurrent_index :taggings, :id, where: INDEX_CONDITION, name: INDEX_NAME # rubocop:disable Migration/PreventIndexCreation
+
+    queue_background_migration_jobs_by_range_at_intervals(
+      Tagging.where(taggable_type: 'Project'),
+      MIGRATION,
+      DELAY_INTERVAL,
+      batch_size: BATCH_SIZE,
+      track_jobs: true
+    )
+  end
+
+  def down
+    remove_concurrent_index_by_name :taggings, INDEX_NAME
+  end
+end