MDEV-8931: (server part of) session state tracking

System variables tracking

include/mysql_com.h

@@ -288,7 +288,7 @@ enum enum_server_command
                            CLIENT_MULTI_RESULTS | \
                            CLIENT_PS_MULTI_RESULTS | \
                            CLIENT_SSL_VERIFY_SERVER_CERT | \
-                            CLIENT_REMEMBER_OPTIONS | \
+                           CLIENT_REMEMBER_OPTIONS | \
                            MARIADB_CLIENT_PROGRESS | \
                            CLIENT_PLUGIN_AUTH | \
                            CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA | \
@@ -556,9 +556,9 @@ enum enum_mysql_set_option
 */
 enum enum_session_state_type
 {
-  SESSION_TRACK_SYSTEM_VARIABLES,                       /* Session system variables */
-  SESSION_TRACK_SCHEMA,                          /* Current schema */
-  SESSION_TRACK_STATE_CHANGE,                  /* track session state changes */
+  SESSION_TRACK_SYSTEM_VARIABLES,             /* Session system variables */
+  SESSION_TRACK_SCHEMA,                       /* Current schema */
+  SESSION_TRACK_STATE_CHANGE,                 /* track session state changes */
   SESSION_TRACK_GTIDS,
   SESSION_TRACK_TRANSACTION_CHARACTERISTICS,  /* Transaction chistics */
   SESSION_TRACK_TRANSACTION_STATE             /* Transaction state */

mysql-test/r/mysqld--help.result

@@ -908,6 +908,8 @@ The following options may be given as the first argument:
  (Defaults to on; use --skip-session-track-schema to disable.)
  --session-track-state-change 
  Track changes to the 'session state'.
+ --session-track-system-variables=name 
+ Track changes in registered system variables.
  --show-slave-auth-info 
  Show user and password in SHOW SLAVE HOSTS on this
  master.
@@ -1392,6 +1394,7 @@ secure-file-priv (No default value)
 server-id 1
 session-track-schema TRUE
 session-track-state-change FALSE
+session-track-system-variables autocommit,character_set_client,character_set_connection,character_set_results,time_zone
 show-slave-auth-info FALSE
 silent-startup FALSE
 skip-grant-tables TRUE

mysql-test/suite/sys_vars/r/session_track_system_variables_basic.result

@@ -0,0 +1,162 @@
+#
+# Variable name : session_track_system_variables
+# Scope         : Global & Session
+#
+# Global - default
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+# Session - default
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+
+# via INFORMATION_SCHEMA.GLOBAL_VARIABLES
+SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'session_track%' ORDER BY VARIABLE_NAME;
+VARIABLE_NAME	VARIABLE_VALUE
+SESSION_TRACK_SCHEMA	ON
+SESSION_TRACK_STATE_CHANGE	OFF
+SESSION_TRACK_SYSTEM_VARIABLES	autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+# via INFORMATION_SCHEMA.SESSION_VARIABLES
+SELECT * FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME LIKE 'session_track%' ORDER BY VARIABLE_NAME;
+VARIABLE_NAME	VARIABLE_VALUE
+SESSION_TRACK_SCHEMA	ON
+SESSION_TRACK_STATE_CHANGE	OFF
+SESSION_TRACK_SYSTEM_VARIABLES	autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+SET @global_saved_tmp =  @@global.session_track_system_variables;
+
+# Altering global variable's value
+SET @@global.session_track_system_variables='autocommit';
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+
+# Altering session variable's value
+SET @@session.session_track_system_variables='autocommit';
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit
+
+# Variables' values in a new session.
+connect  con1,"127.0.0.1",root,,test,$MASTER_MYPORT,;
+# Global - expect "autocommit"
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit
+
+# Session - expect "autocommit"
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit
+
+# Switching to the default connection.
+connection default;
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit
+
+# Test if DEFAULT is working as expected.
+SET @@global.session_track_system_variables = DEFAULT;
+SET @@session.session_track_system_variables = DEFAULT;
+
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+
+# Variables' values in a new session (con2).
+connect  con2,"127.0.0.1",root,,test,$MASTER_MYPORT,;
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+
+# Altering session should not affect global.
+SET @@session.session_track_system_variables = 'sql_mode';
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+sql_mode
+
+# Variables' values in a new session (con3).
+connect  con3,"127.0.0.1",root,,test,$MASTER_MYPORT,;
+# Altering global should not affect session.
+SET @@global.session_track_system_variables = 'sql_mode';
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+sql_mode
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+
+# Switching to the default connection.
+connection default;
+# Testing NULL
+SET @@global.session_track_system_variables = NULL;
+SET @@session.session_track_system_variables = NULL;
+# Global - expect "" instead of NULL
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+NULL
+# Session - expect "" instead of NULL
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+
+# testing with duplicate entries.
+SET @@global.session_track_system_variables= "time_zone";
+SET @@session.session_track_system_variables= "time_zone";
+SET @@global.session_track_system_variables= "sql_mode,sql_mode";
+SET @@session.session_track_system_variables= "sql_mode,sql_mode";
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+sql_mode
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+sql_mode
+
+# testing ordering
+SET @@global.session_track_system_variables= "time_zone,sql_mode";
+SET @@session.session_track_system_variables= "time_zone,sql_mode";
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+sql_mode,time_zone
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+sql_mode,time_zone
+
+# special values
+SET @@global.session_track_system_variables= "*";
+SET @@session.session_track_system_variables= "*";
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+*
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+*
+SET @@global.session_track_system_variables= "";
+SET @@session.session_track_system_variables= "";
+SELECT @@global.session_track_system_variables;
+@@global.session_track_system_variables
+
+SELECT @@session.session_track_system_variables;
+@@session.session_track_system_variables
+
+
+# Restoring the original values.
+SET @@global.session_track_system_variables = @global_saved_tmp;
+# End of tests.

mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result

@@ -3817,6 +3817,20 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	OFF,ON
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
+VARIABLE_NAME	SESSION_TRACK_SYSTEM_VARIABLES
+SESSION_VALUE	autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+GLOBAL_VALUE	autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	autocommit,character_set_client,character_set_connection,character_set_results,time_zone
+VARIABLE_SCOPE	SESSION
+VARIABLE_TYPE	VARCHAR
+VARIABLE_COMMENT	Track changes in registered system variables.
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	NULL
+READ_ONLY	NO
+COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	SKIP_EXTERNAL_LOCKING
 SESSION_VALUE	NULL
 GLOBAL_VALUE	ON

mysql-test/suite/sys_vars/t/session_track_system_variables_basic.test

@@ -0,0 +1,133 @@
+--source include/not_embedded.inc
+
+--echo #
+--echo # Variable name : session_track_system_variables
+--echo # Scope         : Global & Session
+--echo #
+
+--echo # Global - default
+SELECT @@global.session_track_system_variables;
+--echo # Session - default
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # via INFORMATION_SCHEMA.GLOBAL_VARIABLES
+--disable_warnings
+SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'session_track%' ORDER BY VARIABLE_NAME;
+--enable_warnings
+
+--echo # via INFORMATION_SCHEMA.SESSION_VARIABLES
+--disable_warnings
+SELECT * FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME LIKE 'session_track%' ORDER BY VARIABLE_NAME;
+--enable_warnings
+
+# Save the global value to be used to restore the original value.
+SET @global_saved_tmp =  @@global.session_track_system_variables;
+--echo
+
+--echo # Altering global variable's value
+SET @@global.session_track_system_variables='autocommit';
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Altering session variable's value
+SET @@session.session_track_system_variables='autocommit';
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Variables' values in a new session.
+connect (con1,"127.0.0.1",root,,test,$MASTER_MYPORT,);
+
+--echo # Global - expect "autocommit"
+SELECT @@global.session_track_system_variables;
+--echo
+--echo # Session - expect "autocommit"
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Switching to the default connection.
+connection default;
+
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Test if DEFAULT is working as expected.
+SET @@global.session_track_system_variables = DEFAULT;
+SET @@session.session_track_system_variables = DEFAULT;
+--echo
+
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Variables' values in a new session (con2).
+connect (con2,"127.0.0.1",root,,test,$MASTER_MYPORT,);
+
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Altering session should not affect global.
+SET @@session.session_track_system_variables = 'sql_mode';
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Variables' values in a new session (con3).
+connect (con3,"127.0.0.1",root,,test,$MASTER_MYPORT,);
+
+--echo # Altering global should not affect session.
+SET @@global.session_track_system_variables = 'sql_mode';
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # Switching to the default connection.
+connection default;
+
+--echo # Testing NULL
+SET @@global.session_track_system_variables = NULL;
+SET @@session.session_track_system_variables = NULL;
+
+--echo # Global - expect "" instead of NULL
+SELECT @@global.session_track_system_variables;
+--echo # Session - expect "" instead of NULL
+SELECT @@session.session_track_system_variables;
+
+--echo # testing with duplicate entries.
+# Lets first set it to some valid value.
+SET @@global.session_track_system_variables= "time_zone";
+SET @@session.session_track_system_variables= "time_zone";
+# Now set with duplicate entries (must pass)
+SET @@global.session_track_system_variables= "sql_mode,sql_mode";
+SET @@session.session_track_system_variables= "sql_mode,sql_mode";
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # testing ordering
+SET @@global.session_track_system_variables= "time_zone,sql_mode";
+SET @@session.session_track_system_variables= "time_zone,sql_mode";
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+--echo # special values
+SET @@global.session_track_system_variables= "*";
+SET @@session.session_track_system_variables= "*";
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+SET @@global.session_track_system_variables= "";
+SET @@session.session_track_system_variables= "";
+SELECT @@global.session_track_system_variables;
+SELECT @@session.session_track_system_variables;
+--echo
+
+
+--echo # Restoring the original values.
+SET @@global.session_track_system_variables = @global_saved_tmp;
+
+--echo # End of tests.

sql/mysqld.cc

@@ -690,6 +690,14 @@ THD *next_global_thread(THD *thd)
 }
 
 struct system_variables global_system_variables;
+/**
+  Following is just for options parsing, used with a difference against
+  global_system_variables.
+
+  TODO: something should be done to get rid of following variables
+*/
+const char *current_dbug_option="";
+
 struct system_variables max_system_variables;
 struct system_status_var global_status_var;
 
@@ -1463,7 +1471,6 @@ my_bool plugins_are_initialized= FALSE;
 #ifndef DBUG_OFF
 static const char* default_dbug_option;
 #endif
-const char *current_dbug_option="";
 #ifdef HAVE_LIBWRAP
 const char *libwrapName= NULL;
 int allow_severity = LOG_INFO;
@@ -5278,6 +5285,17 @@ static int init_server_components()
   }
   plugins_are_initialized= TRUE;  /* Don't separate from init function */
 
+  {
+    Session_tracker session_track_system_variables_check;
+    if (session_track_system_variables_check.
+	server_boot_verify(system_charset_info))
+    {
+      sql_print_error("The variable session_track_system_variables has "
+		      "invalid values.");
+      unireg_abort(1);
+    }
+  }
+
   /* we do want to exit if there are any other unknown options */
   if (remaining_argc > 1)
   {