Bug#99917: Limit connections on the administrative interface

mysql-test/r/admin_max_connections.result

@@ -0,0 +1,75 @@
+#
+# 1. Status variables exist and start at a clean baseline
+#
+SHOW GLOBAL STATUS LIKE 'Admin_connection%';
+Variable_name	Value
+Admin_connection_errors_max_connections	0
+Admin_connections	0
+#
+# 2. Create a user allowed to use the administrative interface
+#
+CREATE USER u_admin;
+GRANT SERVICE_CONNECTION_ADMIN ON *.* TO u_admin;
+#
+# 3. With the default of 0 there is no limit (previous behaviour),
+#    and Admin_connections counts administrative connections only
+#
+SHOW GLOBAL STATUS LIKE 'Admin_connections';
+Variable_name	Value
+Admin_connections	3
+# An ordinary connection must NOT change Admin_connections
+SHOW GLOBAL STATUS LIKE 'Admin_connections';
+Variable_name	Value
+Admin_connections	3
+# All administrative connections are gone again
+SHOW GLOBAL STATUS LIKE 'Admin_connections';
+Variable_name	Value
+Admin_connections	0
+#
+# 4. With admin_max_connections = 2 the third administrative
+#    connection is rejected, and the rejection is counted in
+#    Admin_connection_errors_max_connections only
+#
+SET GLOBAL admin_max_connections = 2;
+# Remember the normal-connection error counter to prove it stays put
+SHOW GLOBAL STATUS LIKE 'Admin_connections';
+Variable_name	Value
+Admin_connections	2
+connect(127.0.0.1,u_admin,,test,ADMIN_PORT,SOURCE_SOCKET);
+ERROR HY000: Too many connections
+SHOW GLOBAL STATUS LIKE 'Admin_connection_errors_max_connections';
+Variable_name	Value
+Admin_connection_errors_max_connections	1
+# The rejection did not leak into Connection_errors_max_connections
+# Connection_errors_max_connections unchanged: OK
+#
+# 5. Ordinary connections are not affected by the admin cap
+#
+SELECT 1 AS ordinary_connection_works;
+ordinary_connection_works
+1
+#
+# 6. Closing an administrative connection frees a slot
+#
+SELECT 1 AS admin_slot_freed;
+admin_slot_freed
+1
+#
+# 7. Lowering the cap below the number of open administrative
+#    connections affects only new connections
+#
+SET GLOBAL admin_max_connections = 1;
+SELECT 1 AS existing_admin_conn_alive;
+existing_admin_conn_alive
+1
+connect(127.0.0.1,u_admin,,test,ADMIN_PORT,SOURCE_SOCKET);
+ERROR HY000: Too many connections
+#
+# 8. Setting the value back to 0 removes the limit again
+#
+SET GLOBAL admin_max_connections = 0;
+#
+# Cleanup
+#
+DROP USER u_admin;
+SET GLOBAL admin_max_connections = DEFAULT;

mysql-test/r/all_persisted_variables.result

@@ -46,17 +46,17 @@ include/assert.inc [Expect 500+ variables in the table. Due to open Bugs, we are
 
 # Test SET PERSIST
 
-include/assert.inc [Expect 450 persisted variables in the table.]
+include/assert.inc [Expect 451 persisted variables in the table.]
 
 ************************************************************
 * 3. Restart server, it must preserve the persisted variable
 *    settings. Verify persisted configuration.
 ************************************************************
 # restart
 
-include/assert.inc [Expect 450 persisted variables in persisted_variables table.]
-include/assert.inc [Expect 450 persisted variables shown as PERSISTED in variables_info table.]
-include/assert.inc [Expect 450 persisted variables with matching peristed and global values.]
+include/assert.inc [Expect 451 persisted variables in persisted_variables table.]
+include/assert.inc [Expect 451 persisted variables shown as PERSISTED in variables_info table.]
+include/assert.inc [Expect 451 persisted variables with matching peristed and global values.]
 
 ************************************************************
 * 4. Test RESET PERSIST IF EXISTS. Verify persisted variable

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

@@ -29,6 +29,11 @@ The following options may be given as the first argument:
  System. Attempt to specify a network namespace for a
  platform that doesn't support it results in error during
  socket creation.
+ --admin-max-connections=# 
+ The maximum number of concurrent client connections
+ permitted on the administrative interface
+ (admin_address/admin_port). 0 (the default) means no
+ limit.
  --admin-port=#      Port number to use for service connection, built-in
  default (33062)
  --admin-ssl-ca=name CA file in PEM format (check OpenSSL docs) for
@@ -1642,6 +1647,7 @@ Variables (--variable-name=value)
 activate-all-roles-on-login FALSE
 activate-mandatory-roles TRUE
 admin-address (No default value)
+admin-max-connections 0
 admin-port 33062
 admin-ssl-ca (No default value)
 admin-ssl-capath (No default value)

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

@@ -0,0 +1,128 @@
+SET @start_value = @@global.admin_max_connections;
+SELECT @start_value;
+@start_value
+0
+'#--------------------FN_DYNVARS_XXX_01------------------------#'
+SET @@global.admin_max_connections = 5000;
+SET @@global.admin_max_connections = DEFAULT;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+0
+'#---------------------FN_DYNVARS_XXX_02-------------------------#'
+SET @@global.admin_max_connections = @start_value;
+SELECT @@global.admin_max_connections = 0;
+@@global.admin_max_connections = 0
+1
+'#--------------------FN_DYNVARS_XXX_03------------------------#'
+SET @@global.admin_max_connections = 100000;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+100000
+SET @@global.admin_max_connections = 99999;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+99999
+SET @@global.admin_max_connections = 65536;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+65536
+SET @@global.admin_max_connections = 0;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+0
+SET @@global.admin_max_connections = 1;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+1
+'#--------------------FN_DYNVARS_XXX_04-------------------------#'
+SET @@global.admin_max_connections = -1;
+Warnings:
+Warning	1292	Truncated incorrect admin_max_connections value: '-1'
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+0
+SET @@global.admin_max_connections = 100000000000;
+Warnings:
+Warning	1292	Truncated incorrect admin_max_connections value: '100000000000'
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+100000
+SET @@global.admin_max_connections = 10000.01;
+ERROR 42000: Incorrect argument type to variable 'admin_max_connections'
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+100000
+SET @@global.admin_max_connections = -1024;
+Warnings:
+Warning	1292	Truncated incorrect admin_max_connections value: '-1024'
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+0
+SET @@global.admin_max_connections = 100001;
+Warnings:
+Warning	1292	Truncated incorrect admin_max_connections value: '100001'
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+100000
+SET @@global.admin_max_connections = ON;
+ERROR 42000: Incorrect argument type to variable 'admin_max_connections'
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+100000
+SET @@global.admin_max_connections = 'test';
+ERROR 42000: Incorrect argument type to variable 'admin_max_connections'
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+100000
+'#-------------------FN_DYNVARS_XXX_05----------------------------#'
+SET @@session.admin_max_connections = 4096;
+ERROR HY000: Variable 'admin_max_connections' is a GLOBAL variable and should be set with SET GLOBAL
+SELECT @@session.admin_max_connections;
+ERROR HY000: Variable 'admin_max_connections' is a GLOBAL variable
+'#----------------------FN_DYNVARS_XXX_06------------------------#'
+SELECT @@global.admin_max_connections = VARIABLE_VALUE
+FROM performance_schema.global_variables
+WHERE VARIABLE_NAME='admin_max_connections';
+@@global.admin_max_connections = VARIABLE_VALUE
+1
+SELECT @@admin_max_connections = VARIABLE_VALUE
+FROM performance_schema.session_variables
+WHERE VARIABLE_NAME='admin_max_connections';
+@@admin_max_connections = VARIABLE_VALUE
+1
+'#---------------------FN_DYNVARS_XXX_07----------------------#'
+SET @@global.admin_max_connections = TRUE;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+1
+SET @@global.admin_max_connections = FALSE;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+0
+'#---------------------FN_DYNVARS_XXX_08----------------------#'
+SET @@global.admin_max_connections = 5000;
+SELECT @@admin_max_connections = @@global.admin_max_connections;
+@@admin_max_connections = @@global.admin_max_connections
+1
+'#---------------------FN_DYNVARS_XXX_09----------------------#'
+SET admin_max_connections = 6000;
+ERROR HY000: Variable 'admin_max_connections' is a GLOBAL variable and should be set with SET GLOBAL
+SELECT @@admin_max_connections;
+@@admin_max_connections
+5000
+SET local.admin_max_connections = 7000;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'local.admin_max_connections = 7000' at line 1
+SELECT local.admin_max_connections;
+ERROR 42S02: Unknown table 'local' in field list
+SET global.admin_max_connections = 8000;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'global.admin_max_connections = 8000' at line 1
+SELECT global.admin_max_connections;
+ERROR 42S02: Unknown table 'global' in field list
+SELECT admin_max_connections;
+ERROR 42S22: Unknown column 'admin_max_connections' in 'field list'
+SELECT @@session.admin_max_connections;
+ERROR HY000: Variable 'admin_max_connections' is a GLOBAL variable
+SET @@global.admin_max_connections = @start_value;
+SELECT @@global.admin_max_connections;
+@@global.admin_max_connections
+0