Some changes on example files.

Example/my.cnf.MariaDB-10.11

@@ -896,6 +896,26 @@ tmp_table_size = 768M
 #tmp_table_size = 2048M
 
 
+## - optimizer_switch
+## -
+## - see:
+## -     https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_optimizer_switch
+## -     https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_optimizer_switch
+## -
+## -     The optimizer_switch system variable enables control over optimizer
+## -     behavior. The value of this variable is a set of flags, each of which
+## -     has a value of on or off to indicate whether the corresponding optimizer
+## -     behavior is enabled or disabled. This variable has global and session
+## -     values and can be changed at runtime. The global default can be set at
+## -     server startup.
+## -
+## -     To see the current set of optimizer flags, select the variable value:
+## -
+## -        mysql> SELECT @@optimizer_switch\G
+## -
+#optimizer_switch = ''
+
+
 ## - angepasste Einstellungen 
 ## ------------------------------------------
 
@@ -1003,8 +1023,43 @@ query-cache-size = 128M
 ## - query cache
 ## -------------
 
-optimizer_switch = 'rowid_filter=off'
-optimizer_use_condition_selectivity = 1
+
+## - optimizer_switch
+## -
+## - see: 
+## -     https://mariadb.com/kb/en/server-system-variables/#optimizer_switch
+## -     https://mariadb.com/kb/en/optimizer-switch
+## -
+## -     Description: A series of flags for controlling the query optimizer. 
+## -     See 'https://mariadb.com/kb/en/optimizer-switch/' for defaults, and 
+## -     a comparison to MySQL. 
+## -
+## -     To see the current set of optimizer flags, select the variable value: 
+## -
+## -        mysql> SELECT @@optimizer_switch\G
+## -
+#optimizer_switch = 'rowid_filter=off'
+
+
+## - optimizer_use_condition_selectivity
+## -
+## -    Description: Controls which statistics can be used by the optimizer when 
+## -    looking for the best query execution plan.
+## -
+## -        1 Use selectivity of predicates as in MariaDB 5.5.
+## -
+## -        2 Use selectivity of all range predicates supported by indexes.
+## -
+## -        3 Use selectivity of all range predicates estimated without histogram.
+## -
+## -        4 Use selectivity of all range predicates estimated with histogram.
+## -
+## -        5 Additionally use selectivity of certain non-range predicates calculated 
+## -          on record sample.
+## -
+## -  Default Value: 4 (>= MariaDB 10.4.1), 1 (<= MariaDB 10.4.0) 
+## -
+#optimizer_use_condition_selectivity = 1
 
 
 # This group is only read by MariaDB-10.3 servers.