Bug#28234 - global/session scope - documentation vs implementation

Several system variables did not behave like system variables should do.
When trying to SET them or use them in SELECT, they were reported as
"unknown system variable". But they appeared in SHOW VARIABLES.

This has been fixed by removing the "fixed_vars" array of variables
and integrating the variables into the normal system variables chain.
All of these variables do now behave as read-only global-only
variables. Trying to SET them tells they are read-only, trying to
SELECT the session value tells they are global only. Selecting the
global value works. It delivers the same value as SHOW VARIABLES.


mysql-test/r/variables-notembedded.result:
  Bug#28234 - global/session scope - documentation vs implementation
  New test result.
mysql-test/r/variables.result:
  Bug#28234 - global/session scope - documentation vs implementation
  New test result.
mysql-test/t/variables-notembedded.test:
  Bug#28234 - global/session scope - documentation vs implementation
  Added a test for each moved variable that is not present in an
  embedded server.
mysql-test/t/variables.test:
  Bug#28234 - global/session scope - documentation vs implementation
  Added a test for each moved variable that is also present in an
  embedded server.
sql/item_func.cc:
  Bug#28234 - global/session scope - documentation vs implementation
  Added SHOW_BOOL to some Item_func_get_system_var methods.
sql/set_var.cc:
  Bug#28234 - global/session scope - documentation vs implementation
  Moved all variables from the "fixed_vars" array into the normal
  system variables chain by using the new variable class sys_var_const.
  Removed the fixed_show_vars array and its initialization in
  enumerate_sys_vars().
  Removed mysql_append_static_vars(), which added fixed_vars arrays
  to the fixed_show_vars array.
sql/set_var.h:
  Bug#28234 - global/session scope - documentation vs implementation
  Added the new system variable class sys_var_const.
  Removed declaration of mysql_append_static_vars().
sql/slave.cc:
  Bug#28234 - global/session scope - documentation vs implementation
  Moved the definition of show_slave_skip_errors() from sql_repl.cc
  to here and renamed it to print_slave_skip_errors().
  Changed print_slave_skip_errors() to create a static buffer with
  a printable version of the error numbers set.
  Added a call of print_slave_skip_errors() to init_slave_skip_errors().
sql/slave.h:
  Bug#28234 - global/session scope - documentation vs implementation
  Added declaration of slave_skip_error_names.
sql/sql_repl.cc:
  Bug#28234 - global/session scope - documentation vs implementation
  Moved all variables from the "fixed_vars" array into the normal
  system variables chain by using the new variable class sys_var_const.
  Moved the definition of show_slave_skip_errors() to slave.cc and
  modified it to compute the string once at server initialization only.
  Removed the call to mysql_append_static_vars().

10 files changed, 1063 insertions, 145 deletions

diff --git a/mysql-test/r/variables-notembedded.result b/mysql-test/r/variables-notembedded.result
index 48a1719e2c7..571b6605674 100644
--- a/mysql-test/r/variables-notembedded.result
+++ b/mysql-test/r/variables-notembedded.result
@@ -15,3 +15,95 @@ slave_skip_errors	3,100,137,643,1752
 ---- Clean Up ----
 set global slave_net_timeout=default;
 set global sql_slave_skip_counter= 0;
+
+#
+SHOW VARIABLES like 'log_slave_updates';
+Variable_name	Value
+log_slave_updates	OFF
+SELECT @@session.log_slave_updates;
+ERROR HY000: Variable 'log_slave_updates' is a GLOBAL variable
+SELECT @@global.log_slave_updates;
+@@global.log_slave_updates
+0
+SET @@session.log_slave_updates= true;
+ERROR HY000: Variable 'log_slave_updates' is a read only variable
+SET @@global.log_slave_updates= true;
+ERROR HY000: Variable 'log_slave_updates' is a read only variable
+#
+SHOW VARIABLES like 'relay_log';
+Variable_name	Value
+relay_log	
+SELECT @@session.relay_log;
+ERROR HY000: Variable 'relay_log' is a GLOBAL variable
+SELECT @@global.relay_log;
+@@global.relay_log
+NULL
+SET @@session.relay_log= 'x';
+ERROR HY000: Variable 'relay_log' is a read only variable
+SET @@global.relay_log= 'x';
+ERROR HY000: Variable 'relay_log' is a read only variable
+#
+SHOW VARIABLES like 'relay_log_index';
+Variable_name	Value
+relay_log_index	
+SELECT @@session.relay_log_index;
+ERROR HY000: Variable 'relay_log_index' is a GLOBAL variable
+SELECT @@global.relay_log_index;
+@@global.relay_log_index
+NULL
+SET @@session.relay_log_index= 'x';
+ERROR HY000: Variable 'relay_log_index' is a read only variable
+SET @@global.relay_log_index= 'x';
+ERROR HY000: Variable 'relay_log_index' is a read only variable
+#
+SHOW VARIABLES like 'relay_log_info_file';
+Variable_name	Value
+relay_log_info_file	relay-log.info
+SELECT @@session.relay_log_info_file;
+ERROR HY000: Variable 'relay_log_info_file' is a GLOBAL variable
+SELECT @@global.relay_log_info_file;
+@@global.relay_log_info_file
+relay-log.info
+SET @@session.relay_log_info_file= 'x';
+ERROR HY000: Variable 'relay_log_info_file' is a read only variable
+SET @@global.relay_log_info_file= 'x';
+ERROR HY000: Variable 'relay_log_info_file' is a read only variable
+#
+SHOW VARIABLES like 'relay_log_space_limit';
+Variable_name	Value
+relay_log_space_limit	0
+SELECT @@session.relay_log_space_limit;
+ERROR HY000: Variable 'relay_log_space_limit' is a GLOBAL variable
+SELECT @@global.relay_log_space_limit;
+@@global.relay_log_space_limit
+0
+SET @@session.relay_log_space_limit= 7;
+ERROR HY000: Variable 'relay_log_space_limit' is a read only variable
+SET @@global.relay_log_space_limit= 7;
+ERROR HY000: Variable 'relay_log_space_limit' is a read only variable
+#
+SHOW VARIABLES like 'slave_load_tmpdir';
+Variable_name	Value
+slave_load_tmpdir	#
+SELECT @@session.slave_load_tmpdir;
+ERROR HY000: Variable 'slave_load_tmpdir' is a GLOBAL variable
+SELECT @@global.slave_load_tmpdir;
+@@global.slave_load_tmpdir
+#
+SET @@session.slave_load_tmpdir= 'x';
+ERROR HY000: Variable 'slave_load_tmpdir' is a read only variable
+SET @@global.slave_load_tmpdir= 'x';
+ERROR HY000: Variable 'slave_load_tmpdir' is a read only variable
+#
+SHOW VARIABLES like 'slave_skip_errors';
+Variable_name	Value
+slave_skip_errors	3,100,137,643,1752
+SELECT @@session.slave_skip_errors;
+ERROR HY000: Variable 'slave_skip_errors' is a GLOBAL variable
+SELECT @@global.slave_skip_errors;
+@@global.slave_skip_errors
+3,100,137,643,1752
+SET @@session.slave_skip_errors= 7;
+ERROR HY000: Variable 'slave_skip_errors' is a read only variable
+SET @@global.slave_skip_errors= 7;
+ERROR HY000: Variable 'slave_skip_errors' is a read only variable
diff --git a/mysql-test/r/variables.result b/mysql-test/r/variables.result
index c52f7f3578e..878416b4537 100644
--- a/mysql-test/r/variables.result
+++ b/mysql-test/r/variables.result
@@ -1011,3 +1011,342 @@ SET GLOBAL log_output = 0;
 ERROR 42000: Variable 'log_output' can't be set to the value of '0'
 
 # -- End of Bug#34820.
+
+#
+SHOW VARIABLES like 'ft_max_word_len';
+Variable_name	Value
+ft_max_word_len	84
+SELECT @@session.ft_max_word_len;
+ERROR HY000: Variable 'ft_max_word_len' is a GLOBAL variable
+SELECT @@global.ft_max_word_len;
+@@global.ft_max_word_len
+84
+SET @@session.ft_max_word_len= 7;
+ERROR HY000: Variable 'ft_max_word_len' is a read only variable
+SET @@global.ft_max_word_len= 7;
+ERROR HY000: Variable 'ft_max_word_len' is a read only variable
+#
+SHOW VARIABLES like 'ft_min_word_len';
+Variable_name	Value
+ft_min_word_len	4
+SELECT @@session.ft_min_word_len;
+ERROR HY000: Variable 'ft_min_word_len' is a GLOBAL variable
+SELECT @@global.ft_min_word_len;
+@@global.ft_min_word_len
+4
+SET @@session.ft_min_word_len= 7;
+ERROR HY000: Variable 'ft_min_word_len' is a read only variable
+SET @@global.ft_min_word_len= 7;
+ERROR HY000: Variable 'ft_min_word_len' is a read only variable
+#
+SHOW VARIABLES like 'ft_query_expansion_limit';
+Variable_name	Value
+ft_query_expansion_limit	20
+SELECT @@session.ft_query_expansion_limit;
+ERROR HY000: Variable 'ft_query_expansion_limit' is a GLOBAL variable
+SELECT @@global.ft_query_expansion_limit;
+@@global.ft_query_expansion_limit
+20
+SET @@session.ft_query_expansion_limit= 7;
+ERROR HY000: Variable 'ft_query_expansion_limit' is a read only variable
+SET @@global.ft_query_expansion_limit= 7;
+ERROR HY000: Variable 'ft_query_expansion_limit' is a read only variable
+#
+SHOW VARIABLES like 'ft_stopword_file';
+Variable_name	Value
+ft_stopword_file	(built-in)
+SELECT @@session.ft_stopword_file;
+ERROR HY000: Variable 'ft_stopword_file' is a GLOBAL variable
+SELECT @@global.ft_stopword_file;
+@@global.ft_stopword_file
+(built-in)
+SET @@session.ft_stopword_file= 'x';
+ERROR HY000: Variable 'ft_stopword_file' is a read only variable
+SET @@global.ft_stopword_file= 'x';
+ERROR HY000: Variable 'ft_stopword_file' is a read only variable
+#
+SHOW VARIABLES like 'back_log';
+Variable_name	Value
+back_log	50
+SELECT @@session.back_log;
+ERROR HY000: Variable 'back_log' is a GLOBAL variable
+SELECT @@global.back_log;
+@@global.back_log
+50
+SET @@session.back_log= 7;
+ERROR HY000: Variable 'back_log' is a read only variable
+SET @@global.back_log= 7;
+ERROR HY000: Variable 'back_log' is a read only variable
+#
+SHOW VARIABLES like 'large_files_support';
+Variable_name	Value
+large_files_support	#
+SELECT @@session.large_files_support;
+ERROR HY000: Variable 'large_files_support' is a GLOBAL variable
+SELECT @@global.large_files_support;
+@@global.large_files_support
+#
+SET @@session.large_files_support= true;
+ERROR HY000: Variable 'large_files_support' is a read only variable
+SET @@global.large_files_support= true;
+ERROR HY000: Variable 'large_files_support' is a read only variable
+#
+SHOW VARIABLES like 'character_sets_dir';
+Variable_name	Value
+character_sets_dir	#
+SELECT @@session.character_sets_dir;
+ERROR HY000: Variable 'character_sets_dir' is a GLOBAL variable
+SELECT @@global.character_sets_dir;
+@@global.character_sets_dir
+#
+SET @@session.character_sets_dir= 'x';
+ERROR HY000: Variable 'character_sets_dir' is a read only variable
+SET @@global.character_sets_dir= 'x';
+ERROR HY000: Variable 'character_sets_dir' is a read only variable
+#
+SHOW VARIABLES like 'init_file';
+Variable_name	Value
+init_file	#
+SELECT @@session.init_file;
+ERROR HY000: Variable 'init_file' is a GLOBAL variable
+SELECT @@global.init_file;
+@@global.init_file
+#
+SET @@session.init_file= 'x';
+ERROR HY000: Variable 'init_file' is a read only variable
+SET @@global.init_file= 'x';
+ERROR HY000: Variable 'init_file' is a read only variable
+#
+SHOW VARIABLES like 'language';
+Variable_name	Value
+language	#
+SELECT @@session.language;
+ERROR HY000: Variable 'language' is a GLOBAL variable
+SELECT @@global.language;
+@@global.language
+#
+SET @@session.language= 'x';
+ERROR HY000: Variable 'language' is a read only variable
+SET @@global.language= 'x';
+ERROR HY000: Variable 'language' is a read only variable
+#
+SHOW VARIABLES like 'large_page_size';
+Variable_name	Value
+large_page_size	#
+SELECT @@session.large_page_size;
+ERROR HY000: Variable 'large_page_size' is a GLOBAL variable
+SELECT @@global.large_page_size;
+@@global.large_page_size
+#
+SET @@session.large_page_size= 7;
+ERROR HY000: Variable 'large_page_size' is a read only variable
+SET @@global.large_page_size= 7;
+ERROR HY000: Variable 'large_page_size' is a read only variable
+#
+SHOW VARIABLES like 'large_pages';
+Variable_name	Value
+large_pages	#
+SELECT @@session.large_pages;
+ERROR HY000: Variable 'large_pages' is a GLOBAL variable
+SELECT @@global.large_pages;
+@@global.large_pages
+#
+SET @@session.large_pages= true;
+ERROR HY000: Variable 'large_pages' is a read only variable
+SET @@global.large_pages= true;
+ERROR HY000: Variable 'large_pages' is a read only variable
+#
+SHOW VARIABLES like 'log_bin';
+Variable_name	Value
+log_bin	OFF
+SELECT @@session.log_bin;
+ERROR HY000: Variable 'log_bin' is a GLOBAL variable
+SELECT @@global.log_bin;
+@@global.log_bin
+0
+SET @@session.log_bin= true;
+ERROR HY000: Variable 'log_bin' is a read only variable
+SET @@global.log_bin= true;
+ERROR HY000: Variable 'log_bin' is a read only variable
+#
+SHOW VARIABLES like 'log_error';
+Variable_name	Value
+log_error	#
+SELECT @@session.log_error;
+ERROR HY000: Variable 'log_error' is a GLOBAL variable
+SELECT @@global.log_error;
+@@global.log_error
+#
+SET @@session.log_error= 'x';
+ERROR HY000: Variable 'log_error' is a read only variable
+SET @@global.log_error= 'x';
+ERROR HY000: Variable 'log_error' is a read only variable
+#
+SHOW VARIABLES like 'lower_case_file_system';
+Variable_name	Value
+lower_case_file_system	#
+SELECT @@session.lower_case_file_system;
+ERROR HY000: Variable 'lower_case_file_system' is a GLOBAL variable
+SELECT @@global.lower_case_file_system;
+@@global.lower_case_file_system
+#
+SET @@session.lower_case_file_system= true;
+ERROR HY000: Variable 'lower_case_file_system' is a read only variable
+SET @@global.lower_case_file_system= true;
+ERROR HY000: Variable 'lower_case_file_system' is a read only variable
+#
+SHOW VARIABLES like 'lower_case_table_names';
+Variable_name	Value
+lower_case_table_names	#
+SELECT @@session.lower_case_table_names;
+ERROR HY000: Variable 'lower_case_table_names' is a GLOBAL variable
+SELECT @@global.lower_case_table_names;
+@@global.lower_case_table_names
+#
+SET @@session.lower_case_table_names= 7;
+ERROR HY000: Variable 'lower_case_table_names' is a read only variable
+SET @@global.lower_case_table_names= 7;
+ERROR HY000: Variable 'lower_case_table_names' is a read only variable
+#
+SHOW VARIABLES like 'myisam_recover_options';
+Variable_name	Value
+myisam_recover_options	OFF
+SELECT @@session.myisam_recover_options;
+ERROR HY000: Variable 'myisam_recover_options' is a GLOBAL variable
+SELECT @@global.myisam_recover_options;
+@@global.myisam_recover_options
+OFF
+SET @@session.myisam_recover_options= 'x';
+ERROR HY000: Variable 'myisam_recover_options' is a read only variable
+SET @@global.myisam_recover_options= 'x';
+ERROR HY000: Variable 'myisam_recover_options' is a read only variable
+#
+SHOW VARIABLES like 'open_files_limit';
+Variable_name	Value
+open_files_limit	#
+SELECT @@session.open_files_limit;
+ERROR HY000: Variable 'open_files_limit' is a GLOBAL variable
+SELECT @@global.open_files_limit;
+@@global.open_files_limit
+#
+SET @@session.open_files_limit= 7;
+ERROR HY000: Variable 'open_files_limit' is a read only variable
+SET @@global.open_files_limit= 7;
+ERROR HY000: Variable 'open_files_limit' is a read only variable
+#
+SHOW VARIABLES like 'pid_file';
+Variable_name	Value
+pid_file	#
+SELECT @@session.pid_file;
+ERROR HY000: Variable 'pid_file' is a GLOBAL variable
+SELECT @@global.pid_file;
+@@global.pid_file
+#
+SET @@session.pid_file= 'x';
+ERROR HY000: Variable 'pid_file' is a read only variable
+SET @@global.pid_file= 'x';
+ERROR HY000: Variable 'pid_file' is a read only variable
+#
+SHOW VARIABLES like 'plugin_dir';
+Variable_name	Value
+plugin_dir	#
+SELECT @@session.plugin_dir;
+ERROR HY000: Variable 'plugin_dir' is a GLOBAL variable
+SELECT @@global.plugin_dir;
+@@global.plugin_dir
+#
+SET @@session.plugin_dir= 'x';
+ERROR HY000: Variable 'plugin_dir' is a read only variable
+SET @@global.plugin_dir= 'x';
+ERROR HY000: Variable 'plugin_dir' is a read only variable
+#
+SHOW VARIABLES like 'port';
+Variable_name	Value
+port	#
+SELECT @@session.port;
+ERROR HY000: Variable 'port' is a GLOBAL variable
+SELECT @@global.port;
+@@global.port
+#
+SET @@session.port= 7;
+ERROR HY000: Variable 'port' is a read only variable
+SET @@global.port= 7;
+ERROR HY000: Variable 'port' is a read only variable
+#
+SHOW VARIABLES like 'protocol_version';
+Variable_name	Value
+protocol_version	10
+SELECT @@session.protocol_version;
+ERROR HY000: Variable 'protocol_version' is a GLOBAL variable
+SELECT @@global.protocol_version;
+@@global.protocol_version
+10
+SET @@session.protocol_version= 7;
+ERROR HY000: Variable 'protocol_version' is a read only variable
+SET @@global.protocol_version= 7;
+ERROR HY000: Variable 'protocol_version' is a read only variable
+#
+SHOW VARIABLES like 'skip_external_locking';
+Variable_name	Value
+skip_external_locking	ON
+SELECT @@session.skip_external_locking;
+ERROR HY000: Variable 'skip_external_locking' is a GLOBAL variable
+SELECT @@global.skip_external_locking;
+@@global.skip_external_locking
+1
+SET @@session.skip_external_locking= true;
+ERROR HY000: Variable 'skip_external_locking' is a read only variable
+SET @@global.skip_external_locking= true;
+ERROR HY000: Variable 'skip_external_locking' is a read only variable
+#
+SHOW VARIABLES like 'skip_networking';
+Variable_name	Value
+skip_networking	OFF
+SELECT @@session.skip_networking;
+ERROR HY000: Variable 'skip_networking' is a GLOBAL variable
+SELECT @@global.skip_networking;
+@@global.skip_networking
+0
+SET @@session.skip_networking= true;
+ERROR HY000: Variable 'skip_networking' is a read only variable
+SET @@global.skip_networking= true;
+ERROR HY000: Variable 'skip_networking' is a read only variable
+#
+SHOW VARIABLES like 'skip_show_database';
+Variable_name	Value
+skip_show_database	OFF
+SELECT @@session.skip_show_database;
+ERROR HY000: Variable 'skip_show_database' is a GLOBAL variable
+SELECT @@global.skip_show_database;
+@@global.skip_show_database
+0
+SET @@session.skip_show_database= true;
+ERROR HY000: Variable 'skip_show_database' is a read only variable
+SET @@global.skip_show_database= true;
+ERROR HY000: Variable 'skip_show_database' is a read only variable
+#
+SHOW VARIABLES like 'socket';
+Variable_name	Value
+socket	#
+SELECT @@session.socket;
+ERROR HY000: Variable 'socket' is a GLOBAL variable
+SELECT @@global.socket;
+@@global.socket
+#
+SET @@session.socket= 'x';
+ERROR HY000: Variable 'socket' is a read only variable
+SET @@global.socket= 'x';
+ERROR HY000: Variable 'socket' is a read only variable
+#
+SHOW VARIABLES like 'thread_stack';
+Variable_name	Value
+thread_stack	#
+SELECT @@session.thread_stack;
+ERROR HY000: Variable 'thread_stack' is a GLOBAL variable
+SELECT @@global.thread_stack;
+@@global.thread_stack
+#
+SET @@session.thread_stack= 7;
+ERROR HY000: Variable 'thread_stack' is a read only variable
+SET @@global.thread_stack= 7;
+ERROR HY000: Variable 'thread_stack' is a read only variable
diff --git a/mysql-test/t/variables-notembedded.test b/mysql-test/t/variables-notembedded.test
index 79011a89b36..823fecb8791 100644
--- a/mysql-test/t/variables-notembedded.test
+++ b/mysql-test/t/variables-notembedded.test
@@ -28,3 +28,83 @@ set global slave_net_timeout=default;
 # sql_slave_skip_counter is write-only, so we can't save previous
 # value and restore it here.  That's ok, because it's normally 0.
 set global sql_slave_skip_counter= 0;
+
+#
+# Bug#28234 - global/session scope - documentation vs implementation
+#
+--echo
+#
+# Additional variables fixed from sql_repl.cc.
+#
+--echo #
+SHOW VARIABLES like 'log_slave_updates';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.log_slave_updates;
+SELECT @@global.log_slave_updates;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.log_slave_updates= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.log_slave_updates= true;
+#
+--echo #
+SHOW VARIABLES like 'relay_log';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.relay_log;
+SELECT @@global.relay_log;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.relay_log= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.relay_log= 'x';
+#
+--echo #
+SHOW VARIABLES like 'relay_log_index';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.relay_log_index;
+SELECT @@global.relay_log_index;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.relay_log_index= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.relay_log_index= 'x';
+#
+--echo #
+SHOW VARIABLES like 'relay_log_info_file';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.relay_log_info_file;
+SELECT @@global.relay_log_info_file;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.relay_log_info_file= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.relay_log_info_file= 'x';
+#
+--echo #
+SHOW VARIABLES like 'relay_log_space_limit';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.relay_log_space_limit;
+SELECT @@global.relay_log_space_limit;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.relay_log_space_limit= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.relay_log_space_limit= 7;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'slave_load_tmpdir';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.slave_load_tmpdir;
+--replace_column 1 #
+SELECT @@global.slave_load_tmpdir;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.slave_load_tmpdir= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.slave_load_tmpdir= 'x';
+#
+--echo #
+SHOW VARIABLES like 'slave_skip_errors';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.slave_skip_errors;
+SELECT @@global.slave_skip_errors;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.slave_skip_errors= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.slave_skip_errors= 7;
+#
diff --git a/mysql-test/t/variables.test b/mysql-test/t/variables.test
index e98436fa62c..1ef114b1a16 100644
--- a/mysql-test/t/variables.test
+++ b/mysql-test/t/variables.test
@@ -793,3 +793,299 @@ SET GLOBAL log_output = 0;
 --echo
 --echo # -- End of Bug#34820.
 
+#
+# Bug#28234 - global/session scope - documentation vs implementation
+#
+--echo
+--echo #
+SHOW VARIABLES like 'ft_max_word_len';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.ft_max_word_len;
+SELECT @@global.ft_max_word_len;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.ft_max_word_len= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.ft_max_word_len= 7;
+#
+--echo #
+SHOW VARIABLES like 'ft_min_word_len';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.ft_min_word_len;
+SELECT @@global.ft_min_word_len;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.ft_min_word_len= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.ft_min_word_len= 7;
+#
+--echo #
+SHOW VARIABLES like 'ft_query_expansion_limit';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.ft_query_expansion_limit;
+SELECT @@global.ft_query_expansion_limit;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.ft_query_expansion_limit= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.ft_query_expansion_limit= 7;
+#
+--echo #
+SHOW VARIABLES like 'ft_stopword_file';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.ft_stopword_file;
+SELECT @@global.ft_stopword_file;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.ft_stopword_file= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.ft_stopword_file= 'x';
+#
+# Additional variables fixed.
+#
+--echo #
+SHOW VARIABLES like 'back_log';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.back_log;
+SELECT @@global.back_log;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.back_log= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.back_log= 7;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'large_files_support';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.large_files_support;
+--replace_column 1 #
+SELECT @@global.large_files_support;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.large_files_support= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.large_files_support= true;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'character_sets_dir';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.character_sets_dir;
+--replace_column 1 #
+SELECT @@global.character_sets_dir;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.character_sets_dir= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.character_sets_dir= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'init_file';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.init_file;
+--replace_column 1 #
+SELECT @@global.init_file;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.init_file= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.init_file= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'language';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.language;
+--replace_column 1 #
+SELECT @@global.language;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.language= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.language= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'large_page_size';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.large_page_size;
+--replace_column 1 #
+SELECT @@global.large_page_size;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.large_page_size= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.large_page_size= 7;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'large_pages';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.large_pages;
+--replace_column 1 #
+SELECT @@global.large_pages;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.large_pages= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.large_pages= true;
+#
+--echo #
+SHOW VARIABLES like 'log_bin';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.log_bin;
+SELECT @@global.log_bin;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.log_bin= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.log_bin= true;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'log_error';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.log_error;
+--replace_column 1 #
+SELECT @@global.log_error;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.log_error= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.log_error= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'lower_case_file_system';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.lower_case_file_system;
+--replace_column 1 #
+SELECT @@global.lower_case_file_system;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.lower_case_file_system= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.lower_case_file_system= true;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'lower_case_table_names';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.lower_case_table_names;
+--replace_column 1 #
+SELECT @@global.lower_case_table_names;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.lower_case_table_names= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.lower_case_table_names= 7;
+#
+--echo #
+SHOW VARIABLES like 'myisam_recover_options';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.myisam_recover_options;
+SELECT @@global.myisam_recover_options;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.myisam_recover_options= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.myisam_recover_options= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'open_files_limit';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.open_files_limit;
+--replace_column 1 #
+SELECT @@global.open_files_limit;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.open_files_limit= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.open_files_limit= 7;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'pid_file';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.pid_file;
+--replace_column 1 #
+SELECT @@global.pid_file;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.pid_file= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.pid_file= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'plugin_dir';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.plugin_dir;
+--replace_column 1 #
+SELECT @@global.plugin_dir;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.plugin_dir= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.plugin_dir= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'port';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.port;
+--replace_column 1 #
+SELECT @@global.port;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.port= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.port= 7;
+#
+--echo #
+SHOW VARIABLES like 'protocol_version';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.protocol_version;
+SELECT @@global.protocol_version;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.protocol_version= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.protocol_version= 7;
+#
+--echo #
+SHOW VARIABLES like 'skip_external_locking';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.skip_external_locking;
+SELECT @@global.skip_external_locking;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.skip_external_locking= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.skip_external_locking= true;
+#
+--echo #
+SHOW VARIABLES like 'skip_networking';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.skip_networking;
+SELECT @@global.skip_networking;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.skip_networking= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.skip_networking= true;
+#
+--echo #
+SHOW VARIABLES like 'skip_show_database';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.skip_show_database;
+SELECT @@global.skip_show_database;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.skip_show_database= true;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.skip_show_database= true;
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'socket';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.socket;
+--replace_column 1 #
+SELECT @@global.socket;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.socket= 'x';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.socket= 'x';
+#
+--echo #
+--replace_column 2 #
+SHOW VARIABLES like 'thread_stack';
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.thread_stack;
+--replace_column 1 #
+SELECT @@global.thread_stack;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@session.thread_stack= 7;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@global.thread_stack= 7;
+#
diff --git a/sql/item_func.cc b/sql/item_func.cc
index e117adc3cd0..edcb9776a2b 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4855,6 +4855,7 @@ void Item_func_get_system_var::fix_length_and_dec()
       max_length= MAX_BLOB_WIDTH;
       decimals=NOT_FIXED_DEC;
       break;
+    case SHOW_BOOL:
     case SHOW_MY_BOOL:
       unsigned_flag= FALSE;
       max_length= 1;
@@ -4882,6 +4883,7 @@ enum Item_result Item_func_get_system_var::result_type() const
 {
   switch (var->show_type())
   {
+    case SHOW_BOOL:
     case SHOW_MY_BOOL:
     case SHOW_INT:
     case SHOW_LONG:
@@ -4904,6 +4906,7 @@ enum_field_types Item_func_get_system_var::field_type() const
 {
   switch (var->show_type())
   {
+    case SHOW_BOOL:
     case SHOW_MY_BOOL:
     case SHOW_INT:
     case SHOW_LONG:
@@ -4922,6 +4925,10 @@ enum_field_types Item_func_get_system_var::field_type() const
 }
 
 
+/*
+  Uses var, var_type, component, cache_present, used_query_id, thd,
+  cached_llval, null_value, cached_null_value
+*/
 #define get_sys_var_safe(type) \
 do { \
   type value; \
@@ -4975,6 +4982,7 @@ longlong Item_func_get_system_var::val_int()
     case SHOW_LONG:     get_sys_var_safe (ulong);
     case SHOW_LONGLONG: get_sys_var_safe (longlong);
     case SHOW_HA_ROWS:  get_sys_var_safe (ha_rows);
+    case SHOW_BOOL:     get_sys_var_safe (bool);
     case SHOW_MY_BOOL:  get_sys_var_safe (my_bool);
     case SHOW_DOUBLE:
       {
@@ -5072,6 +5080,7 @@ String* Item_func_get_system_var::val_str(String* str)
     case SHOW_LONG:
     case SHOW_LONGLONG:
     case SHOW_HA_ROWS:
+    case SHOW_BOOL:
     case SHOW_MY_BOOL:
       str->set (val_int(), collation.collation);
       break;
@@ -5164,6 +5173,7 @@ double Item_func_get_system_var::val_real()
     case SHOW_LONG:
     case SHOW_LONGLONG:
     case SHOW_HA_ROWS:
+    case SHOW_BOOL:
     case SHOW_MY_BOOL:
         cached_dval= (double) val_int();
         cache_present|= GET_SYS_VAR_CACHE_DOUBLE;
diff --git a/sql/set_var.cc b/sql/set_var.cc
index 7d1acc8e4fb..07ab82c77e0 100644
--- a/sql/set_var.cc
+++ b/sql/set_var.cc
@@ -77,7 +77,6 @@ extern ulong ndb_report_thresh_binlog_mem_usage;
 extern CHARSET_INFO *character_set_filesystem;
 
 
-static DYNAMIC_ARRAY fixed_show_vars;
 static HASH system_variable_hash;
 
 const char *bool_type_names[]= { "OFF", "ON", NullS };
@@ -174,6 +173,9 @@ sys_auto_increment_offset(&vars, "auto_increment_offset",
 static sys_var_bool_ptr	sys_automatic_sp_privileges(&vars, "automatic_sp_privileges",
 					      &sp_automatic_privileges);
 
+static sys_var_const            sys_back_log(&vars, "back_log",
+                                             OPT_GLOBAL, SHOW_LONG,
+                                             (uchar*) &back_log);
 static sys_var_const_str       sys_basedir(&vars, "basedir", mysql_home);
 static sys_var_long_ptr	sys_binlog_cache_size(&vars, "binlog_cache_size",
 					      &binlog_cache_size);
@@ -181,6 +183,11 @@ static sys_var_thd_binlog_format sys_binlog_format(&vars, "binlog_format",
                                             &SV::binlog_format);
 static sys_var_thd_ulong	sys_bulk_insert_buff_size(&vars, "bulk_insert_buffer_size",
 						  &SV::bulk_insert_buff_size);
+static sys_var_const            sys_character_sets_dir(&vars,
+                                                       "character_sets_dir",
+                                                       OPT_GLOBAL, SHOW_CHAR,
+                                                       (uchar*)
+                                                       mysql_charsets_dir);
 static sys_var_character_set_sv
 sys_character_set_server(&vars, "character_set_server",
                          &SV::collation_server, &default_charset_info, 0,
@@ -249,14 +256,31 @@ static sys_var_long_ptr	sys_expire_logs_days(&vars, "expire_logs_days",
 					     &expire_logs_days);
 static sys_var_bool_ptr	sys_flush(&vars, "flush", &myisam_flush);
 static sys_var_long_ptr	sys_flush_time(&vars, "flush_time", &flush_time);
-static sys_var_str             sys_ft_boolean_syntax(&vars, "ft_boolean_syntax",
-                                         sys_check_ftb_syntax,
-                                         sys_update_ftb_syntax,
-                                         sys_default_ftb_syntax,
-                                         ft_boolean_syntax);
+static sys_var_str      sys_ft_boolean_syntax(&vars, "ft_boolean_syntax",
+                                              sys_check_ftb_syntax,
+                                              sys_update_ftb_syntax,
+                                              sys_default_ftb_syntax,
+                                              ft_boolean_syntax);
+static sys_var_const    sys_ft_max_word_len(&vars, "ft_max_word_len",
+                                            OPT_GLOBAL, SHOW_LONG,
+                                            (uchar*) &ft_max_word_len);
+static sys_var_const    sys_ft_min_word_len(&vars, "ft_min_word_len",
+                                            OPT_GLOBAL, SHOW_LONG,
+                                            (uchar*) &ft_min_word_len);
+static sys_var_const    sys_ft_query_expansion_limit(&vars,
+                                                     "ft_query_expansion_limit",
+                                                     OPT_GLOBAL, SHOW_LONG,
+                                                     (uchar*)
+                                                     &ft_query_expansion_limit);
+static sys_var_const    sys_ft_stopword_file(&vars, "ft_stopword_file",
+                                             OPT_GLOBAL, SHOW_CHAR_PTR,
+                                             (uchar*) &ft_stopword_file);
 sys_var_str             sys_init_connect(&vars, "init_connect", 0,
                                          sys_update_init_connect,
                                          sys_default_init_connect,0);
+static sys_var_const    sys_init_file(&vars, "init_file",
+                                      OPT_GLOBAL, SHOW_CHAR_PTR,
+                                      (uchar*) &opt_init_file);
 sys_var_str             sys_init_slave(&vars, "init_slave", 0,
                                        sys_update_init_slave,
                                        sys_default_init_slave,0);
@@ -274,14 +298,37 @@ static sys_var_key_cache_long	sys_key_cache_division_limit(&vars, "key_cache_div
 static sys_var_key_cache_long  sys_key_cache_age_threshold(&vars, "key_cache_age_threshold",
 						     offsetof(KEY_CACHE,
 							      param_age_threshold));
+static sys_var_const    sys_language(&vars, "language",
+                                     OPT_GLOBAL, SHOW_CHAR,
+                                     (uchar*) language);
+static sys_var_const    sys_large_files_support(&vars, "large_files_support",
+                                                OPT_GLOBAL, SHOW_BOOL,
+                                                (uchar*) &opt_large_files);
+static sys_var_const    sys_large_page_size(&vars, "large_page_size",
+                                            OPT_GLOBAL, SHOW_INT,
+                                            (uchar*) &opt_large_page_size);
+static sys_var_const    sys_large_pages(&vars, "large_pages",
+                                        OPT_GLOBAL, SHOW_MY_BOOL,
+                                        (uchar*) &opt_large_pages);
 static sys_var_bool_ptr	sys_local_infile(&vars, "local_infile",
 					 &opt_local_infile);
+#ifdef HAVE_MLOCKALL
+static sys_var_const    sys_locked_in_memory(&vars, "locked_in_memory",
+                                             OPT_GLOBAL, SHOW_MY_BOOL,
+                                             (uchar*) &locked_in_memory);
+#endif
+static sys_var_const    sys_log_bin(&vars, "log_bin",
+                                    OPT_GLOBAL, SHOW_BOOL,
+                                    (uchar*) &opt_bin_log);
 static sys_var_trust_routine_creators
 sys_trust_routine_creators(&vars, "log_bin_trust_routine_creators",
                            &trust_function_creators);
 static sys_var_bool_ptr       
 sys_trust_function_creators(&vars, "log_bin_trust_function_creators",
                             &trust_function_creators);
+static sys_var_const    sys_log_error(&vars, "log_error",
+                                      OPT_GLOBAL, SHOW_CHAR,
+                                      (uchar*) log_error_file);
 static sys_var_bool_ptr
   sys_log_queries_not_using_indexes(&vars, "log_queries_not_using_indexes",
                                     &opt_log_queries_not_using_indexes);
@@ -296,6 +343,16 @@ static sys_var_thd_bool	sys_sql_low_priority_updates(&vars, "sql_low_priority_up
 						     &SV::low_priority_updates,
 						     fix_low_priority_updates);
 #endif
+static sys_var_const    sys_lower_case_file_system(&vars,
+                                                   "lower_case_file_system",
+                                                   OPT_GLOBAL, SHOW_MY_BOOL,
+                                                   (uchar*)
+                                                   &lower_case_file_system);
+static sys_var_const    sys_lower_case_table_names(&vars,
+                                                   "lower_case_table_names",
+                                                   OPT_GLOBAL, SHOW_INT,
+                                                   (uchar*)
+                                                   &lower_case_table_names);
 static sys_var_thd_ulong_session_readonly sys_max_allowed_packet(&vars, "max_allowed_packet",
 					       &SV::max_allowed_packet);
 static sys_var_long_ptr	sys_max_binlog_cache_size(&vars, "max_binlog_cache_size",
@@ -359,6 +416,10 @@ static sys_var_thd_ulong       sys_multi_range_count(&vars, "multi_range_count",
 static sys_var_long_ptr	sys_myisam_data_pointer_size(&vars, "myisam_data_pointer_size",
                                                     &myisam_data_pointer_size);
 static sys_var_thd_ulonglong	sys_myisam_max_sort_file_size(&vars, "myisam_max_sort_file_size", &SV::myisam_max_sort_file_size, fix_myisam_max_sort_file_size, 1);
+static sys_var_const sys_myisam_recover_options(&vars, "myisam_recover_options",
+                                                OPT_GLOBAL, SHOW_CHAR_PTR,
+                                                (uchar*)
+                                                &myisam_recover_options_str);
 static sys_var_thd_ulong       sys_myisam_repair_threads(&vars, "myisam_repair_threads", &SV::myisam_repair_threads);
 static sys_var_thd_ulong	sys_myisam_sort_buffer_size(&vars, "myisam_sort_buffer_size", &SV::myisam_sort_buff_size);
 static sys_var_bool_ptr	sys_myisam_use_mmap(&vars, "myisam_use_mmap",
@@ -369,6 +430,13 @@ static sys_var_thd_enum         sys_myisam_stats_method(&vars, "myisam_stats_met
                                                 &myisam_stats_method_typelib,
                                                 NULL);
 
+#ifdef __NT__
+/* purecov: begin inspected */
+static sys_var_const            sys_named_pipe(&vars, "named_pipe",
+                                               OPT_GLOBAL, SHOW_MY_BOOL,
+                                               (uchar*) &opt_enable_named_pipe);
+/* purecov: end */
+#endif
 static sys_var_thd_ulong_session_readonly sys_net_buffer_length(&vars, "net_buffer_length",
 					      &SV::net_buffer_length);
 static sys_var_thd_ulong	sys_net_read_timeout(&vars, "net_read_timeout",
@@ -387,12 +455,29 @@ static sys_var_bool_ptr_readonly sys_old_mode(&vars, "old",
 sys_var_thd_bool                sys_old_alter_table(&vars, "old_alter_table",
                                             &SV::old_alter_table);
 sys_var_thd_bool                sys_old_passwords(&vars, "old_passwords", &SV::old_passwords);
+static sys_var_const            sys_open_files_limit(&vars, "open_files_limit",
+                                                     OPT_GLOBAL, SHOW_LONG,
+                                                     (uchar*)
+                                                     &open_files_limit);
 static sys_var_thd_ulong        sys_optimizer_prune_level(&vars, "optimizer_prune_level",
                                                   &SV::optimizer_prune_level);
 static sys_var_thd_ulong        sys_optimizer_search_depth(&vars, "optimizer_search_depth",
                                                    &SV::optimizer_search_depth);
+static sys_var_const            sys_pid_file(&vars, "pid_file",
+                                             OPT_GLOBAL, SHOW_CHAR,
+                                             (uchar*) pidfile_name);
+static sys_var_const            sys_plugin_dir(&vars, "plugin_dir",
+                                               OPT_GLOBAL, SHOW_CHAR,
+                                               (uchar*) opt_plugin_dir);
+static sys_var_const            sys_port(&vars, "port",
+                                         OPT_GLOBAL, SHOW_INT,
+                                         (uchar*) &mysqld_port);
 static sys_var_thd_ulong        sys_preload_buff_size(&vars, "preload_buffer_size",
                                               &SV::preload_buff_size);
+static sys_var_const            sys_protocol_version(&vars, "protocol_version",
+                                                     OPT_GLOBAL, SHOW_INT,
+                                                     (uchar*)
+                                                     &protocol_version);
 static sys_var_thd_ulong	sys_read_buff_size(&vars, "read_buffer_size",
 					   &SV::read_buff_size);
 static sys_var_opt_readonly	sys_readonly(&vars, "read_only", &opt_readonly);
@@ -414,6 +499,45 @@ static sys_var_thd_ulong	sys_query_alloc_block_size(&vars, "query_alloc_block_si
 static sys_var_thd_ulong	sys_query_prealloc_size(&vars, "query_prealloc_size",
 						&SV::query_prealloc_size,
 						0, fix_thd_mem_root);
+#ifdef HAVE_SMEM
+/* purecov: begin tested */
+static sys_var_const    sys_shared_memory(&vars, "shared_memory",
+                                          OPT_GLOBAL, SHOW_MY_BOOL,
+                                          (uchar*)
+                                          &opt_enable_shared_memory);
+static sys_var_const    sys_shared_memory_base_name(&vars,
+                                                    "shared_memory_base_name",
+                                                    OPT_GLOBAL, SHOW_CHAR_PTR,
+                                                    (uchar*)
+                                                    &shared_memory_base_name);
+/* purecov: end */
+#endif
+static sys_var_const    sys_skip_external_locking(&vars,
+                                                  "skip_external_locking",
+                                                  OPT_GLOBAL, SHOW_MY_BOOL,
+                                                  (uchar*)
+                                                  &my_disable_locking);
+static sys_var_const    sys_skip_networking(&vars, "skip_networking",
+                                            OPT_GLOBAL, SHOW_BOOL,
+                                            (uchar*) &opt_disable_networking);
+static sys_var_const    sys_skip_show_database(&vars, "skip_show_database",
+                                            OPT_GLOBAL, SHOW_BOOL,
+                                            (uchar*) &opt_skip_show_db);
+#ifdef HAVE_SYS_UN_H
+static sys_var_const    sys_socket(&vars, "socket",
+                                   OPT_GLOBAL, SHOW_CHAR_PTR,
+                                   (uchar*) &mysqld_unix_port);
+#endif
+#ifdef HAVE_THR_SETCONCURRENCY
+/* purecov: begin tested */
+static sys_var_const    sys_thread_concurrency(&vars, "thread_concurrency",
+                                               OPT_GLOBAL, SHOW_LONG,
+                                               (uchar*) &concurrency);
+/* purecov: end */
+#endif
+static sys_var_const    sys_thread_stack(&vars, "thread_stack",
+                                         OPT_GLOBAL, SHOW_LONG,
+                                         (uchar*) &my_thread_stack_size);
 static sys_var_readonly        sys_tmpdir(&vars, "tmpdir", OPT_GLOBAL, SHOW_CHAR, get_tmpdir);
 static sys_var_thd_ulong	sys_trans_alloc_block_size(&vars, "transaction_alloc_block_size",
 						   &SV::trans_alloc_block_size,
@@ -764,59 +888,6 @@ static sys_var_log_output sys_var_log_output_state(&vars, "log_output", &log_out
 					    &log_output_typelib, 0);
 
 
-/*
-  Additional variables (not derived from sys_var class, not accessible as
-  @@varname in SELECT or SET). Sorted in alphabetical order to facilitate
-  maintenance - SHOW VARIABLES will sort its output.
-  TODO: remove this list completely
-*/
-
-#define FIXED_VARS_SIZE (sizeof(fixed_vars) / sizeof(SHOW_VAR))
-static SHOW_VAR fixed_vars[]= {
-  {"back_log",                (char*) &back_log,                    SHOW_LONG},
-  {"character_sets_dir",      mysql_charsets_dir,                   SHOW_CHAR},
-  {"ft_max_word_len",         (char*) &ft_max_word_len,             SHOW_LONG},
-  {"ft_min_word_len",         (char*) &ft_min_word_len,             SHOW_LONG},
-  {"ft_query_expansion_limit",(char*) &ft_query_expansion_limit,    SHOW_LONG},
-  {"ft_stopword_file",        (char*) &ft_stopword_file,            SHOW_CHAR_PTR},
-  {"init_file",               (char*) &opt_init_file,               SHOW_CHAR_PTR},
-  {"language",                language,                             SHOW_CHAR},
-  {"large_files_support",     (char*) &opt_large_files,             SHOW_BOOL},
-  {"large_page_size",         (char*) &opt_large_page_size,         SHOW_INT},
-  {"large_pages",             (char*) &opt_large_pages,             SHOW_MY_BOOL},
-#ifdef HAVE_MLOCKALL
-  {"locked_in_memory",	      (char*) &locked_in_memory,	    SHOW_MY_BOOL},
-#endif
-  {"log_bin",                 (char*) &opt_bin_log,                 SHOW_BOOL},
-  {"log_error",               (char*) log_error_file,               SHOW_CHAR},
-  {"lower_case_file_system",  (char*) &lower_case_file_system,      SHOW_MY_BOOL},
-  {"lower_case_table_names",  (char*) &lower_case_table_names,      SHOW_INT},
-  {"myisam_recover_options",  (char*) &myisam_recover_options_str,  SHOW_CHAR_PTR},
-#ifdef __NT__
-  {"named_pipe",	      (char*) &opt_enable_named_pipe,       SHOW_MY_BOOL},
-#endif
-  {"open_files_limit",	      (char*) &open_files_limit,	    SHOW_LONG},
-  {"pid_file",                (char*) pidfile_name,                 SHOW_CHAR},
-  {"plugin_dir",              (char*) opt_plugin_dir,               SHOW_CHAR},
-  {"port",                    (char*) &mysqld_port,                 SHOW_INT},
-  {"protocol_version",        (char*) &protocol_version,            SHOW_INT},
-#ifdef HAVE_SMEM
-  {"shared_memory",           (char*) &opt_enable_shared_memory,    SHOW_MY_BOOL},
-  {"shared_memory_base_name", (char*) &shared_memory_base_name,     SHOW_CHAR_PTR},
-#endif
-  {"skip_external_locking",   (char*) &my_disable_locking,          SHOW_MY_BOOL},
-  {"skip_networking",         (char*) &opt_disable_networking,      SHOW_BOOL},
-  {"skip_show_database",      (char*) &opt_skip_show_db,            SHOW_BOOL},
-#ifdef HAVE_SYS_UN_H
-  {"socket",                  (char*) &mysqld_unix_port,            SHOW_CHAR_PTR},
-#endif
-#ifdef HAVE_THR_SETCONCURRENCY
-  {"thread_concurrency",      (char*) &concurrency,                 SHOW_LONG},
-#endif
-  {"thread_stack",            (char*) &my_thread_stack_size,        SHOW_LONG},
-};
-
-
 bool sys_var::check(THD *thd, set_var *var)
 {
   var->save_result.ulonglong_value= var->value->val_int();
@@ -3135,14 +3206,12 @@ static int show_cmp(SHOW_VAR *a, SHOW_VAR *b)
 SHOW_VAR* enumerate_sys_vars(THD *thd, bool sorted)
 {
   int count= system_variable_hash.records, i;
-  int fixed_count= fixed_show_vars.elements;
-  int size= sizeof(SHOW_VAR) * (count + fixed_count + 1);
+  int size= sizeof(SHOW_VAR) * (count + 1);
   SHOW_VAR *result= (SHOW_VAR*) thd->alloc(size);
 
   if (result)
   {
-    SHOW_VAR *show= result + fixed_count;
-    memcpy(result, fixed_show_vars.buffer, fixed_count * sizeof(SHOW_VAR));
+    SHOW_VAR *show= result;
 
     for (i= 0; i < count; i++)
     {
@@ -3155,7 +3224,7 @@ SHOW_VAR* enumerate_sys_vars(THD *thd, bool sorted)
 
     /* sort into order */
     if (sorted)
-      my_qsort(result, count + fixed_count, sizeof(SHOW_VAR),
+      my_qsort(result, count, sizeof(SHOW_VAR),
                (qsort_cmp) show_cmp);
     
     /* make last element empty */
@@ -3183,13 +3252,6 @@ int set_var_init()
   
   for (sys_var *var=vars.first; var; var= var->next, count++);
 
-  if (my_init_dynamic_array(&fixed_show_vars, sizeof(SHOW_VAR),
-                            FIXED_VARS_SIZE + 64, 64))
-    goto error;
-
-  fixed_show_vars.elements= FIXED_VARS_SIZE;
-  memcpy(fixed_show_vars.buffer, fixed_vars, sizeof(fixed_vars));
-
   if (hash_init(&system_variable_hash, system_charset_info, count, 0,
                 0, (hash_get_key) get_sys_var_length, 0, HASH_UNIQUE))
     goto error;
@@ -3217,28 +3279,6 @@ error:
 void set_var_free()
 {
   hash_free(&system_variable_hash);
-  delete_dynamic(&fixed_show_vars);
-}
-
-
-/*
-  Add elements to the dynamic list of read-only system variables.
-  
-  SYNOPSIS
-    mysql_append_static_vars()
-    show_vars	Pointer to start of array
-    count       Number of elements
-  
-  RETURN VALUES
-    0           SUCCESS
-    otherwise   FAILURE
-*/
-int mysql_append_static_vars(const SHOW_VAR *show_vars, uint count)
-{
-  for (; count > 0; count--, show_vars++)
-    if (insert_dynamic(&fixed_show_vars, (uchar*) show_vars))
-      return 1;
-  return 0;
 }
 
 
diff --git a/sql/set_var.h b/sql/set_var.h
index ab819694e09..6b62d62706e 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -929,6 +929,34 @@ public:
 };
 
 
+/**
+  Global-only, read-only variable. E.g. command line option.
+*/
+
+class sys_var_const: public sys_var
+{
+public:
+  enum_var_type var_type;
+  SHOW_TYPE show_type_value;
+  uchar *ptr;
+  sys_var_const(sys_var_chain *chain, const char *name_arg, enum_var_type type,
+                SHOW_TYPE show_type_arg, uchar *ptr_arg)
+    :sys_var(name_arg), var_type(type),
+    show_type_value(show_type_arg), ptr(ptr_arg)
+  { chain_sys_var(chain); }
+  bool update(THD *thd, set_var *var) { return 1; }
+  bool check_default(enum_var_type type) { return 1; }
+  bool check_type(enum_var_type type) { return type != var_type; }
+  bool check_update_type(Item_result type) { return 1; }
+  uchar *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base)
+  {
+    return ptr;
+  }
+  SHOW_TYPE show_type() { return show_type_value; }
+  bool is_readonly() const { return 1; }
+};
+
+
 class sys_var_have_option: public sys_var
 {
 protected:
@@ -1317,7 +1345,6 @@ struct sys_var_with_base
 
 int set_var_init();
 void set_var_free();
-int mysql_append_static_vars(const SHOW_VAR *show_vars, uint count);
 SHOW_VAR* enumerate_sys_vars(THD *thd, bool sorted);
 int mysql_add_sys_var_chain(sys_var *chain, struct my_option *long_options);
 int mysql_del_sys_var_chain(sys_var *chain);
diff --git a/sql/slave.cc b/sql/slave.cc
index 0040b69f8de..6708f2ddd60 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -49,6 +49,7 @@
 #define MAX_SLAVE_RETRY_PAUSE 5
 bool use_slave_mask = 0;
 MY_BITMAP slave_error_mask;
+char slave_skip_error_names[SHOW_VAR_FUNC_BUFF_SIZE];
 
 typedef bool (*CHECK_KILLED_FUNC)(THD*,void*);
 
@@ -275,6 +276,64 @@ err:
 }
 
 
+/**
+  Convert slave skip errors bitmap into a printable string.
+*/
+
+static void print_slave_skip_errors(void)
+{
+  /*
+    To be safe, we want 10 characters of room in the buffer for a number
+    plus terminators. Also, we need some space for constant strings.
+    10 characters must be sufficient for a number plus {',' | '...'}
+    plus a NUL terminator. That is a max 6 digit number.
+  */
+  const int MIN_ROOM= 10;
+  DBUG_ENTER("print_slave_skip_errors");
+  DBUG_ASSERT(sizeof(slave_skip_error_names) > MIN_ROOM);
+  DBUG_ASSERT(MAX_SLAVE_ERROR <= 999999); // 6 digits
+
+  if (!use_slave_mask || bitmap_is_clear_all(&slave_error_mask))
+  {
+    /* purecov: begin tested */
+    memcpy(slave_skip_error_names, STRING_WITH_LEN("OFF"));
+    /* purecov: end */
+  }
+  else if (bitmap_is_set_all(&slave_error_mask))
+  {
+    /* purecov: begin tested */
+    memcpy(slave_skip_error_names, STRING_WITH_LEN("ALL"));
+    /* purecov: end */
+  }
+  else
+  {
+    char *buff= slave_skip_error_names;
+    char *bend= buff + sizeof(slave_skip_error_names);
+    int  errnum;
+
+    for (errnum= 1; errnum < MAX_SLAVE_ERROR; errnum++)
+    {
+      if (bitmap_is_set(&slave_error_mask, errnum))
+      {
+        if (buff + MIN_ROOM >= bend)
+          break; /* purecov: tested */
+        buff= int10_to_str(errnum, buff, 10);
+        *buff++= ',';
+      }
+    }
+    if (buff != slave_skip_error_names)
+      buff--; // Remove last ','
+    if (errnum < MAX_SLAVE_ERROR)
+    {
+      /* Couldn't show all errors */
+      buff= strmov(buff, "..."); /* purecov: tested */
+    }
+    *buff=0;
+  }
+  DBUG_PRINT("init", ("error_names: '%s'", slave_skip_error_names));
+  DBUG_VOID_RETURN;
+}
+
 /*
   Init function to set up array for errors that should be skipped for slave
 
@@ -314,6 +373,8 @@ void init_slave_skip_errors(const char* arg)
     while (!my_isdigit(system_charset_info,*p) && *p)
       p++;
   }
+  /* Convert slave skip errors bitmap into a printable string. */
+  print_slave_skip_errors();
   DBUG_VOID_RETURN;
 }
 
diff --git a/sql/slave.h b/sql/slave.h
index dc2d668c97b..abd63315e62 100644
--- a/sql/slave.h
+++ b/sql/slave.h
@@ -98,6 +98,7 @@ class Master_info;
 
 extern ulong master_retry_count;
 extern MY_BITMAP slave_error_mask;
+extern char slave_skip_error_names[];
 extern bool use_slave_mask;
 extern char *slave_load_tmpdir;
 extern char *master_info_file, *relay_log_info_file;
diff --git a/sql/sql_repl.cc b/sql/sql_repl.cc
index 932b7a67b4d..eac7a50417a 100644
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@@ -1660,64 +1660,38 @@ public:
 
 static sys_var_chain vars = { NULL, NULL };
 
+static sys_var_const    sys_log_slave_updates(&vars, "log_slave_updates",
+                                              OPT_GLOBAL, SHOW_MY_BOOL,
+                                              (uchar*) &opt_log_slave_updates);
+static sys_var_const    sys_relay_log(&vars, "relay_log",
+                                      OPT_GLOBAL, SHOW_CHAR_PTR,
+                                      (uchar*) &opt_relay_logname);
+static sys_var_const    sys_relay_log_index(&vars, "relay_log_index",
+                                      OPT_GLOBAL, SHOW_CHAR_PTR,
+                                      (uchar*) &opt_relaylog_index_name);
+static sys_var_const    sys_relay_log_info_file(&vars, "relay_log_info_file",
+                                      OPT_GLOBAL, SHOW_CHAR_PTR,
+                                      (uchar*) &relay_log_info_file);
 static sys_var_bool_ptr	sys_relay_log_purge(&vars, "relay_log_purge",
 					    &relay_log_purge);
+static sys_var_const    sys_relay_log_space_limit(&vars,
+                                                  "relay_log_space_limit",
+                                                  OPT_GLOBAL, SHOW_LONGLONG,
+                                                  (uchar*)
+                                                  &relay_log_space_limit);
+static sys_var_const    sys_slave_load_tmpdir(&vars, "slave_load_tmpdir",
+                                              OPT_GLOBAL, SHOW_CHAR_PTR,
+                                              (uchar*) &slave_load_tmpdir);
 static sys_var_long_ptr	sys_slave_net_timeout(&vars, "slave_net_timeout",
 					      &slave_net_timeout);
+static sys_var_const    sys_slave_skip_errors(&vars, "slave_skip_errors",
+                                              OPT_GLOBAL, SHOW_CHAR,
+                                              (uchar*) slave_skip_error_names);
 static sys_var_long_ptr	sys_slave_trans_retries(&vars, "slave_transaction_retries",
 						&slave_trans_retries);
 static sys_var_sync_binlog_period sys_sync_binlog_period(&vars, "sync_binlog", &sync_binlog_period);
 static sys_var_slave_skip_counter sys_slave_skip_counter(&vars, "sql_slave_skip_counter");
 
-static int show_slave_skip_errors(THD *thd, SHOW_VAR *var, char *buff);
-
-
-static SHOW_VAR fixed_vars[]= {
-  {"log_slave_updates",       (char*) &opt_log_slave_updates,       SHOW_MY_BOOL},
-  {"relay_log" , (char*) &opt_relay_logname, SHOW_CHAR_PTR},
-  {"relay_log_index", (char*) &opt_relaylog_index_name, SHOW_CHAR_PTR},
-  {"relay_log_info_file", (char*) &relay_log_info_file, SHOW_CHAR_PTR},
-  {"relay_log_space_limit",   (char*) &relay_log_space_limit,       SHOW_LONGLONG},
-  {"slave_load_tmpdir",       (char*) &slave_load_tmpdir,           SHOW_CHAR_PTR},
-  {"slave_skip_errors",       (char*) &show_slave_skip_errors,      SHOW_FUNC},
-};
-
-static int show_slave_skip_errors(THD *thd, SHOW_VAR *var, char *buff)
-{
-  var->type=SHOW_CHAR;
-  var->value= buff;
-  if (!use_slave_mask || bitmap_is_clear_all(&slave_error_mask))
-  {
-    var->value= const_cast<char *>("OFF");
-  }
-  else if (bitmap_is_set_all(&slave_error_mask))
-  {
-    var->value= const_cast<char *>("ALL");
-  }
-  else
-  {
-    /* 10 is enough assuming errors are max 4 digits */
-    int i;
-    var->value= buff;
-    for (i= 1;
-         i < MAX_SLAVE_ERROR &&
-         (buff - var->value) < SHOW_VAR_FUNC_BUFF_SIZE;
-         i++)
-    {
-      if (bitmap_is_set(&slave_error_mask, i))
-      {
-        buff= int10_to_str(i, buff, 10);
-        *buff++= ',';
-      }
-    }
-    if (var->value != buff)
-      buff--;				// Remove last ','
-    if (i < MAX_SLAVE_ERROR)
-      buff= strmov(buff, "...");  // Couldn't show all errors
-    *buff=0;
-  }
-  return 0;
-}
 
 bool sys_var_slave_skip_counter::check(THD *thd, set_var *var)
 {
@@ -1765,8 +1739,6 @@ bool sys_var_sync_binlog_period::update(THD *thd, set_var *var)
 
 int init_replication_sys_vars()
 {
-  mysql_append_static_vars(fixed_vars, sizeof(fixed_vars) / sizeof(SHOW_VAR));
-
   if (mysql_add_sys_var_chain(vars.first, my_long_options))
   {
     /* should not happen */