Fix for bug #29131: SHOW VARIABLES reports variable 'log' but SET

doesn't recognize it
  
This is a 5.1 version of the patch.
  
Problem:
  
'log' and 'log_slow_queries' were "fixed" variables, i.e. they showed up
in SHOW VARIABLES, but could not be used in expressions like 
"select @@log". Also, using them in the SET statement produced an 
incorrect "unknown system variable" error.
  
Solution:

Since as of MySQL 5.1.12 one can enable or disable the general query log
or the slow query log at runtime by changing values of
general_log/slow_query_log, make 'log' and 'log_slow_queries" to be 
synonyms for 'general_log' and 'slow_query_log' respectively.  This 
makes expressions using the '@@var' syntax backward compatible with 
5.0 and SHOW VARIABLES output to be consistent with the SET statement.


mysql-test/r/log_state.result:
  Added a test case for bug #29131.
mysql-test/t/log_state.test:
  Added a test case for bug #29131.
sql/set_var.cc:
  Made the 'log' and 'log_slow_queries' system variables to be synonyms for 'general_log' and 'slow_query_log'.

mysql-test/r/log_state.result

@@ -175,3 +175,66 @@ SET GLOBAL slow_query_log = ON;
 SET GLOBAL READ_ONLY = OFF;
 SET GLOBAL general_log = @old_general_log_state;
 SET GLOBAL slow_query_log = @old_slow_log_state;
+SET @old_general_log_state = @@global.general_log;
+SET @old_slow_log_state = @@global.slow_query_log;
+SHOW VARIABLES LIKE 'general_log';
+Variable_name	Value
+general_log	ON
+SHOW VARIABLES LIKE 'log';
+Variable_name	Value
+log	ON
+SELECT @@general_log, @@log;
+@@general_log	@@log
+1	1
+SET GLOBAL log = 0;
+SHOW VARIABLES LIKE 'general_log';
+Variable_name	Value
+general_log	OFF
+SHOW VARIABLES LIKE 'log';
+Variable_name	Value
+log	OFF
+SELECT @@general_log, @@log;
+@@general_log	@@log
+0	0
+SET GLOBAL general_log = 1;
+SHOW VARIABLES LIKE 'general_log';
+Variable_name	Value
+general_log	ON
+SHOW VARIABLES LIKE 'log';
+Variable_name	Value
+log	ON
+SELECT @@general_log, @@log;
+@@general_log	@@log
+1	1
+SHOW VARIABLES LIKE 'slow_query_log';
+Variable_name	Value
+slow_query_log	OFF
+SHOW VARIABLES LIKE 'log_slow_queries';
+Variable_name	Value
+log_slow_queries	OFF
+SELECT @@slow_query_log, @@log_slow_queries;
+@@slow_query_log	@@log_slow_queries
+0	0
+SET GLOBAL log_slow_queries = 0;
+SHOW VARIABLES LIKE 'slow_query_log';
+Variable_name	Value
+slow_query_log	OFF
+SHOW VARIABLES LIKE 'log_slow_queries';
+Variable_name	Value
+log_slow_queries	OFF
+SELECT @@slow_query_log, @@log_slow_queries;
+@@slow_query_log	@@log_slow_queries
+0	0
+SET GLOBAL slow_query_log = 1;
+SHOW VARIABLES LIKE 'slow_query_log';
+Variable_name	Value
+slow_query_log	ON
+SHOW VARIABLES LIKE 'log_slow_queries';
+Variable_name	Value
+log_slow_queries	ON
+SELECT @@slow_query_log, @@log_slow_queries;
+@@slow_query_log	@@log_slow_queries
+1	1
+SET GLOBAL general_log = @old_general_log_state;
+SET GLOBAL slow_query_log = @old_slow_log_state;
+End of 5.1 tests

mysql-test/t/log_state.test

@@ -179,6 +179,42 @@ SET GLOBAL READ_ONLY = OFF;
 SET GLOBAL general_log = @old_general_log_state;
 SET GLOBAL slow_query_log = @old_slow_log_state;
 
+#
+# Bug #29131: SHOW VARIABLES reports variable 'log' but SET doesn't recognize it
+#
+
+SET @old_general_log_state = @@global.general_log;
+SET @old_slow_log_state = @@global.slow_query_log;
+
+SHOW VARIABLES LIKE 'general_log';
+SHOW VARIABLES LIKE 'log';
+SELECT @@general_log, @@log;
+SET GLOBAL log = 0;
+SHOW VARIABLES LIKE 'general_log';
+SHOW VARIABLES LIKE 'log';
+SELECT @@general_log, @@log;
+SET GLOBAL general_log = 1;
+SHOW VARIABLES LIKE 'general_log';
+SHOW VARIABLES LIKE 'log';
+SELECT @@general_log, @@log;
+
+SHOW VARIABLES LIKE 'slow_query_log';
+SHOW VARIABLES LIKE 'log_slow_queries';
+SELECT @@slow_query_log, @@log_slow_queries;
+SET GLOBAL log_slow_queries = 0;
+SHOW VARIABLES LIKE 'slow_query_log';
+SHOW VARIABLES LIKE 'log_slow_queries';
+SELECT @@slow_query_log, @@log_slow_queries;
+SET GLOBAL slow_query_log = 1;
+SHOW VARIABLES LIKE 'slow_query_log';
+SHOW VARIABLES LIKE 'log_slow_queries';
+SELECT @@slow_query_log, @@log_slow_queries;
+
+SET GLOBAL general_log = @old_general_log_state;
+SET GLOBAL slow_query_log = @old_slow_log_state;
+
+--echo End of 5.1 tests
+
 --enable_ps_protocol
 
 #

sql/set_var.cc

@@ -641,8 +641,14 @@ static sys_var_const_str	sys_license(&vars, "license", STRINGIFY_ARG(LICENSE));
 /* Global variables which enable|disable logging */
 static sys_var_log_state sys_var_general_log(&vars, "general_log", &opt_log,
                                       QUERY_LOG_GENERAL);
+/* Synonym of "general_log" for consistency with SHOW VARIABLES output */
+static sys_var_log_state sys_var_log(&vars, "log", &opt_log,
+                                      QUERY_LOG_GENERAL);
 static sys_var_log_state sys_var_slow_query_log(&vars, "slow_query_log", &opt_slow_log,
                                          QUERY_LOG_SLOW);
+/* Synonym of "slow_query_log" for consistency with SHOW VARIABLES output */
+static sys_var_log_state sys_var_log_slow(&vars, "log_slow_queries",
+                                          &opt_slow_log, QUERY_LOG_SLOW);
 sys_var_str sys_var_general_log_path(&vars, "general_log_file", sys_check_log_path,
 				     sys_update_general_log_path,
 				     sys_default_general_log_path,
@@ -678,10 +684,8 @@ static SHOW_VAR fixed_vars[]= {
 #ifdef HAVE_MLOCKALL
   {"locked_in_memory",	      (char*) &locked_in_memory,	    SHOW_MY_BOOL},
 #endif
-  {"log",                     (char*) &opt_log,                     SHOW_MY_BOOL},
   {"log_bin",                 (char*) &opt_bin_log,                 SHOW_BOOL},
   {"log_error",               (char*) log_error_file,               SHOW_CHAR},
-  {"log_slow_queries",        (char*) &opt_slow_log,                SHOW_MY_BOOL},
   {"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},