Correct the Streams article (#2735)

Resolves #2503

Author: patiencedaur

doc/book/box/stream.rst

@@ -29,8 +29,8 @@ a stream transfers data via the protocol between a client and a server.
 
 ..  _box_stream-features:
 
-New features
-------------
+Features
+--------
 
 The primary purpose of :term:`streams <stream>` is to execute transactions via iproto.
 Every stream has its own identifier, which is unique within the connection.
@@ -45,6 +45,10 @@ The ID is generated on the client side automatically.
 If a user writes their own connector and wants to use streams,
 they must transmit the ``stream_id`` over the iproto protocol.
 
+Interactive transactions over streams only work if
+the ``box.cfg{}`` option :ref:`memtx_use_mvcc_engine <cfg_basic-memtx_use_mvcc_engine>`
+is enabled on the server: ``memtx_use_mvcc_engine = true``.
+
 ..  _box_stream-interaction:
 
 Interaction between streams and transactions
@@ -63,7 +67,7 @@ that transaction will be rolled back if it hasn't been committed before the conn
 
 Example:
 
-.. code-block:: lua
+..  code-block:: lua
 
     local conn = net_box.connect(remote_server_addr)
     local conn_space = conn.space.test
@@ -72,15 +76,15 @@ Example:
 
     -- Begin transaction over an iproto stream:
     stream:begin()
-    space:replace({1})
+    stream_space:replace({1})
 
     -- Empty select, the transaction was not committed.
     -- You can't see it from the requests that do not belong to the
     -- transaction.
+    conn_space:select{}
 
     -- Select returns the previously inserted tuple,
     -- because this select belongs to the transaction:
-    conn_space:select{}
     stream_space:select({})
 
     -- Commit transaction:

locale/ru/LC_MESSAGES/book/box/stream.po

@@ -46,8 +46,8 @@ msgstr ""
 "целиком в рамках одного запроса. ``begin``, ``commit`` и другие TX-"
 "инструкции могут быть отправлены и выполнены в разных запросах."
 
-msgid "New features"
-msgstr "Новые функциональные возможности"
+msgid "Features"
+msgstr "Функциональные возможности"
 
 msgid ""
 "The primary purpose of :term:`streams <stream>` is to execute transactions "
@@ -80,6 +80,15 @@ msgstr ""
 "поддержкой стримов. Используя стримы с пользовательским коннектором, "
 "необходимо передавать ``stream_id`` через протокол iproto."
 
+msgid ""
+"Interactive transactions over streams only work if the ``box.cfg{}`` option "
+":ref:`memtx_use_mvcc_engine <cfg_basic-memtx_use_mvcc_engine>` is enabled on"
+" the server: ``memtx_use_mvcc_engine = true``."
+msgstr ""
+"Чтобы в стримах работали интерактивные транзакции, необходимо включить "
+"параметр ``box.cfg{}`` :ref:`memtx_use_mvcc_engine <cfg_basic-"
+"memtx_use_mvcc_engine>` на сервере: ``memtx_use_mvcc_engine = true``."
+
 msgid "Interaction between streams and transactions"
 msgstr "Взаимодействие между стримами и транзакциями"
 
@@ -122,15 +131,15 @@ msgid ""
 "\n"
 "-- Begin transaction over an iproto stream:\n"
 "stream:begin()\n"
-"space:replace({1})\n"
+"stream_space:replace({1})\n"
 "\n"
 "-- Empty select, the transaction was not committed.\n"
 "-- You can't see it from the requests that do not belong to the\n"
 "-- transaction.\n"
+"conn_space:select{}\n"
 "\n"
 "-- Select returns the previously inserted tuple,\n"
 "-- because this select belongs to the transaction:\n"
-"conn_space:select{}\n"
 "stream_space:select({})\n"
 "\n"
 "-- Commit transaction:\n"
@@ -146,7 +155,7 @@ msgstr ""
 "\n"
 "-- Начать транзакцию через поток iproto:\n"
 "stream:begin()\n"
-"space:replace({1})\n"
+"stream_space:replace({1})\n"
 "\n"
 "-- Пустой select, коммит транзакции не выполнен.\n"
 "-- Ее нельзя увидеть из запросов, не относящихся\n"