1 files changed, 63 insertions, 0 deletions
diff --git a/lib/gitlab/database/async_indexes/index_creator.rb b/lib/gitlab/database/async_indexes/index_creator.rb
new file mode 100644
index 00000000000..00de79ec970
--- /dev/null
+++ b/lib/gitlab/database/async_indexes/index_creator.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Database
+    module AsyncIndexes
+      class IndexCreator
+        include ExclusiveLeaseGuard
+
+        TIMEOUT_PER_ACTION = 1.day
+        STATEMENT_TIMEOUT = 9.hours
+
+        def initialize(async_index)
+          @async_index = async_index
+        end
+
+        def perform
+          try_obtain_lease do
+            if index_exists?
+              log_index_info('Skipping index creation as the index exists')
+            else
+              log_index_info('Creating async index')
+
+              set_statement_timeout do
+                connection.execute(async_index.definition)
+              end
+
+              log_index_info('Finished creating async index')
+            end
+
+            async_index.destroy
+          end
+        end
+
+        private
+
+        attr_reader :async_index
+
+        def index_exists?
+          connection.indexes(async_index.table_name).any? { |index| index.name == async_index.name }
+        end
+
+        def connection
+          @connection ||= ApplicationRecord.connection
+        end
+
+        def lease_timeout
+          TIMEOUT_PER_ACTION
+        end
+
+        def set_statement_timeout
+          connection.execute("SET statement_timeout TO '%ds'" % STATEMENT_TIMEOUT)
+          yield
+        ensure
+          connection.execute('RESET statement_timeout')
+        end
+
+        def log_index_info(message)
+          Gitlab::AppLogger.info(message: message, table_name: async_index.table_name, index_name: async_index.name)
+        end
+      end
+    end
+  end
+end