Resolve file conflicts

Author: patiencedaur

doc/concepts/replication/repl_leader_elect.rst

@@ -122,8 +122,8 @@ Eventually, there will be two sets of nodes with the diverged data,
 and any node from one set is disconnected from any node from the other set with the ``ER_SPLIT_BRAIN`` error.
 
 Once noticing the error, a user can choose any representative from each of the sets and inspect the data on them.
-To correlate the data, the user should remove it from the nodes of one set, and reconnect them to the nodes from the other set that have the correct data.
-
+To correlate the data, the user should remove it from the nodes of one set,
+and reconnect them to the nodes from the other set that have the correct data.
 
 Also, if election is enabled on the node, it won't replicate from any nodes except
 the newest leader. This is done to avoid the issue when a new leader is elected,

doc/how-to/replication/repl_sync.rst

@@ -21,9 +21,16 @@ To control the behavior of synchronous transactions, there exist global
 
     box.cfg{replication_synchro_quorum = <number of instances>}
 
-This option tells how many replicas should confirm the receipt of a synchronous
-transaction before it is committed. Since version :doc:`2.10.0 </release/2.10.0>`,
-this option does not account for anonymous replicas. As a usage example, consider this:
+..  code-block:: lua
+
+    box.cfg{replication_synchro_quorum = "N / 2 + 1"}
+
+This option tells how many replicas should confirm the receipt of a synchronous transaction before it is committed.
+Since version :doc:`2.5.3 </release/2.5.3>`, the parameter supports dynamic evaluation of the quorum number
+(see :ref:`reference for the replication_synchro_quorum parameter <cfg_replication-replication_synchro_quorum>` for details).
+Since version :doc:`2.10.0 </release/2.10.0>`,
+this option does not account for anonymous replicas.
+As a usage example, consider this:
 
 ..  code-block:: lua
 

doc/reference/configuration/cfg_replication.rst

@@ -428,18 +428,39 @@
     This option tells how many replicas should confirm the receipt of a
     synchronous transaction before it can finish its commit.
 
+    Since version :doc:`2.5.3 </release/2.5.3>`,
+    the option supports dynamic evaluation of the quorum number.
+    That is, the number of quorum can be specified not as a constant number, but as a function instead.
+    In this case, the option returns the formula evaluated.
+    The result is treated as an integer number.
+    Once any replicas are added or removed, the expression is re-evaluated automatically.
+
+    For example,
+
+    ..  code-block:: lua
+
+        box.cfg{replication_synchro_quorum = "N / 2 + 1"}
+
+    Where `N` is a current number of registered replicas in a cluster.
+
+    Keep in mind that the example above represents a canonical quorum definition.
+    The formula ``at least 50% of the cluster size + 1`` guarantees data reliability.
+    Using a value less than the canonical one might lead to unexpected results,
+    including a :ref:`split-brain <repl_leader_elect_splitbrain>`.
+
     Since version :doc:`2.10.0 </release/2.10.0>`, this option
     does not account for anonymous replicas.
 
-    It is 1 by default, so synchronous transactions work like asynchronous when
-    not configured. 1 means successful WAL write on master is enough for
-    commit.
+    The default value for this parameter is ``N / 2 + 1``.
 
     It is not used on replicas, so if the master dies, the pending synchronous
     transactions will be kept waiting on the replicas until a new master is elected.
 
+    If the value for this option is set to ``1``, the synchronous transactions work like asynchronous when not configured.
+    `1` means that successful WAL write to the master is enough to commit.
+
     | Type: number
-    | Default: 1
+    | Default: N / 2 + 1 (before version :doc:`2.10.0 </release/2.10.0>`, the default value was 1)
     | Environment variable: TT_REPLICATION_SYNCHRO_QUORUM
     | Dynamic: **yes**
 

locale/ru/LC_MESSAGES/reference/configuration/index.po

@@ -1972,12 +1972,9 @@ msgid ""
 msgstr ""
 
 msgid ""
-"It is 1 by default, so synchronous transactions work like asynchronous when "
-"not configured. 1 means successful WAL write on master is enough for commit."
+"The default value for this parameter is ``N / 2 + 1``."
 msgstr ""
-"По умолчанию она равна 1, поэтому синхронные транзакции работают как "
-"асинхронные, пока они не настроены. 1 означает, что для коммита достаточно "
-"успешной записи в WAL на мастере."
+"По умолчанию значение параметра равно ``N / 2 + 1``."
 
 msgid ""
 "It is not used on replicas, so if the master dies, the pending synchronous "
@@ -1988,6 +1985,14 @@ msgstr ""
 "синхронные транзакции будут ждать на репликах до тех пор, пока не будет "
 "выбран новый мастер."
 
+msgid ""
+"If the value for this option is set to ``1``, the synchronous transactions work like asynchronous when "
+"not configured. `1` means that successful WAL write to the master is enough to commit."
+msgstr ""
+"Если значение параметра равно `1`, синхронные транзакции работают как "
+"асинхронные, пока они не настроены. `1` означает, что для коммита достаточно "
+"успешной записи в WAL на мастере."
+
 msgid ""
 "Since version :doc:`2.5.1 </release/2.5.1>`. For :ref:`synchronous "
 "replication <repl_sync>` only. Tells how many seconds to wait for a "