1 files changed, 63 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/backfill_issue_search_data.rb b/lib/gitlab/background_migration/backfill_issue_search_data.rb
new file mode 100644
index 00000000000..ec206cbfd41
--- /dev/null
+++ b/lib/gitlab/background_migration/backfill_issue_search_data.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+# rubocop:disable Style/Documentation
+
+module Gitlab
+  module BackgroundMigration
+    # Backfills the new `issue_search_data` table, which contains
+    # the tsvector from the issue title and description.
+    class BackfillIssueSearchData
+      include Gitlab::Database::DynamicModelHelpers
+
+      def perform(start_id, stop_id, batch_table, batch_column, sub_batch_size, pause_ms)
+        define_batchable_model(batch_table, connection: ActiveRecord::Base.connection).where(batch_column => start_id..stop_id).each_batch(of: sub_batch_size) do |sub_batch|
+          update_search_data(sub_batch)
+
+          sleep(pause_ms * 0.001)
+        rescue ActiveRecord::StatementInvalid => e
+          raise unless e.cause.is_a?(PG::ProgramLimitExceeded) && e.message.include?('string is too long for tsvector')
+
+          update_search_data_individually(sub_batch, pause_ms)
+        end
+      end
+
+      private
+
+      def update_search_data(relation)
+        relation.klass.connection.execute(
+          <<~SQL
+          INSERT INTO issue_search_data (project_id, issue_id, search_vector, created_at, updated_at)
+          SELECT
+            project_id,
+            id,
+            setweight(to_tsvector('english', LEFT(title, 255)), 'A') || setweight(to_tsvector('english', LEFT(REGEXP_REPLACE(description, '[A-Za-z0-9+/@]{50,}', ' ', 'g'), 1048576)), 'B'),
+            NOW(),
+            NOW()
+          FROM issues
+          WHERE issues.id IN (#{relation.select(:id).to_sql})
+          ON CONFLICT DO NOTHING
+          SQL
+        )
+      end
+
+      def update_search_data_individually(relation, pause_ms)
+        relation.pluck(:id).each do |issue_id|
+          update_search_data(relation.klass.where(id: issue_id))
+
+          sleep(pause_ms * 0.001)
+        rescue ActiveRecord::StatementInvalid => e
+          raise unless e.cause.is_a?(PG::ProgramLimitExceeded) && e.message.include?('string is too long for tsvector')
+
+          logger.error(
+            message: 'Error updating search data: string is too long for tsvector',
+            class: relation.klass.name,
+            model_id: issue_id
+          )
+        end
+      end
+
+      def logger
+        @logger ||= Gitlab::BackgroundMigration::Logger.build
+      end
+    end
+  end
+end