This is patch for the https://jira.mariadb.org/browse/MDEV-9519 issue:

If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.

The causes and fixes:

1. We need to improve processing of changing the auto-increment values
after changing the cluster size.

2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.

3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).

1 files changed, 11 insertions, 0 deletions

diff --git a/sql/sql_class.h b/sql/sql_class.h
index 53e451511d5..f0c486bd172 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -552,6 +552,17 @@ typedef struct system_variables
   ha_rows max_join_size;
   ha_rows expensive_subquery_limit;
   ulong auto_increment_increment, auto_increment_offset;
+#ifdef WITH_WSREP
+  /*
+    Variables with stored values of the auto_increment_increment
+    and auto_increment_offset options that are will be needed when
+    wsrep_auto_increment_control will be set to 'OFF', because the
+    setting it to 'ON' leads to overwriting of the original values
+    (which are set by the user) by calculated values (which are
+    based on the cluster's size):
+  */
+  ulong saved_auto_increment_increment, saved_auto_increment_offset;
+#endif /* WITH_WSREP */
   ulong lock_wait_timeout;
   ulong join_cache_level;
   ulong max_allowed_packet;