Mark sql_defer_foreign keys as obsolete (#3625)

Resolves #3244

Author: p7nov

doc/reference/reference_lua/box_space/_session_settings.rst

@@ -8,28 +8,35 @@ box.space._session_settings
 
 .. data:: _session_settings
 
-    ``_session_settings`` is a temporary system space with a list of settings that
-    may affect behavior, particularly SQL behavior, for the current session.
-    It uses a special engine named 'service'.
-    Every 'service' tuple is created on the fly, that is, new tuples are made every time ``_session_settings`` is accessed.
+    A temporary system space with settings that affect behavior, particularly SQL behavior,
+    for the current session. It uses a special engine named 'service'.
+    Every 'service' tuple is created on the fly, that is, new tuples are made every
+    time ``_session_settings`` is accessed.
     Every settings tuple has two fields: ``name`` (the primary key) and ``value``.
-    The tuples' names and default values are: |br|
-    ``error_marshaling_enabled``: whether
-    :doc:`error objects </reference/reference_lua/box_error/new>` have
-    a special structure. Default = false. |br|
-    ``sql_default_engine``: default :ref:`storage engine <engines-chapter>` for new SQL tables. Default = 'memtx'. |br|
-    ``sql_defer_foreign_keys``: whether foreign-key checks can wait till commit. Default = false. |br|
-    ``sql_full_column_names``: whether a full column name is used in :ref:`SQL result set metadata <box-sql_result_sets>`. Default = false. |br|
-    ``sql_full_metadata``: whether :ref:`SQL result set metadata <box-sql_result_sets>` will have more than just name and type. Default = false. |br|
-    ``sql_parser_debug``: whether to show parser steps for following statements. Default = false. |br|
-    ``sql_recursive_triggers``: whether a triggered statement can activate a :ref:`trigger <sql_create_trigger>`. Default = true. |br|
-    ``sql_reverse_unordered_selects``: whether result rows are usually in reverse order if there is no :ref:`ORDER BY clause <sql_order_by>`. Default = false. |br|
-    ``sql_select_debug``: whether to show execution steps during :ref:`SELECT <sql_select>`. Default = false. |br|
-    ``sql_vdbe_debug``: for use by Tarantool's developers. Default = false. |br|
-    Three requests are possible: :doc:`select </reference/reference_lua/box_space/select>` and :doc:`get </reference/reference_lua/box_space/get>` and :doc:`update </reference/reference_lua/box_space/update>`.
+    The tuples' names and default values are:
+
+    *   ``error_marshaling_enabled``: whether :doc:`error objects </reference/reference_lua/box_error/new>` have
+        a special structure. Default: ``false``.
+    *   ``sql_default_engine``: default :ref:`storage engine <engines-chapter>` for new SQL tables. Default: ``memtx``.
+    *   ``sql_full_column_names``: use full column names in :ref:`SQL result set metadata <box-sql_result_sets>`.
+        Default: ``false``.
+    *   ``sql_full_metadata``: whether :ref:`SQL result set metadata <box-sql_result_sets>` includes more than just name
+        and type. Default:``false``.
+    *   ``sql_parser_debug``: show parser steps for following statements. Default: ``false``.
+    *   ``sql_recursive_triggers``: whether a triggered statement can activate a :ref:`trigger <sql_create_trigger>`.
+        Default: ``true``.
+    *   ``sql_reverse_unordered_selects``: return result rows in reverse order if there is no :ref:`ORDER BY clause <sql_order_by>`.
+        Default: ``false``.
+    *   ``sql_select_debug``: show execution steps during :ref:`SELECT <sql_select>`. Default:``false``.
+    *   ``sql_vdbe_debug``: for internal use. Default:``false``.
+    *   ``sql_defer_foreign_keys``: **(removed in :doc:`2.11.0 </release/2.11.0>`)** whether foreign-key checks can wait till
+        commit. Default: ``false``.
+
+    Three requests are possible: :doc:`select </reference/reference_lua/box_space/select>`, :doc:`get </reference/reference_lua/box_space/get>`
+    and :doc:`update </reference/reference_lua/box_space/update>`.
     For example, after ``s = box.space._session_settings``,
     ``s:select('sql_default_engine')`` probably returns ``{'sql_default_engine', 'memtx'}``, and
     ``s:update('sql_default_engine', {{'=', 'value', 'vinyl'}})`` changes the default engine to 'vinyl'. |br|
     Updating ``sql_parser_debug`` or ``sql_select_debug`` or ``sql_vdbe_debug`` has no effect unless
-    Tarantool was built with -DCMAKE_BUILD_TYPE=Debug. To check if this is so, look at
+    Tarantool was built with ``-DCMAKE_BUILD_TYPE=Debug``. To check if this is so, look at
     ``require('tarantool').build.target``.

doc/reference/reference_sql/sql_statements_and_clauses.rst

@@ -1710,17 +1710,20 @@ to update the
 :ref:`box.space._session_settings <box_space-session_settings>`
 temporary system space.
 
-``setting-name`` can be any one of
-``"error_marshaling_enabled"``.
-``"sql_default_engine"``.
-``"sql_defer_foreign_keys"``,
-``"sql_full_column_names"``,
-``"sql_full_metadata"``,
-``"sql_parser_debug"``,
-``"sql_recursive_triggers"``,
-``"sql_reverse_unordered_selects"``,
-``"sql_select_debug"``,
-``"sql_vdbe_debug"``. The quote marks are necessary.
+``setting-name`` can have the following values:
+
+*   ``"error_marshaling_enabled"``
+*   ``"sql_default_engine"``
+*   ``"sql_full_column_names"``
+*   ``"sql_full_metadata"``
+*   ``"sql_parser_debug"``
+*   ``"sql_recursive_triggers"``
+*   ``"sql_reverse_unordered_selects"``
+*   ``"sql_select_debug"``
+*   ``"sql_vdbe_debug"``
+*   ``"sql_defer_foreign_keys"`` **(removed in :doc:`2.11.0 </release/2.11.0>`)**
+
+The quote marks are necessary.
 
 If ``setting-name`` is ``"sql_default_engine"``, then
 ``setting-value`` can be either 'vinyl' or 'memtx'.