WL#1339 "Add per account max_user_connections limit (maximum number

of concurrent connections for the same account)"

Added support of account specific max_user_connections limit. Made all
user limits to be counted per account instead of the old behavior,
which was per user/host accounting. Added option which enables the old
behavior. Added testing of these to the test suite.

(After review version).


client/mysqltest.c:
  Extended mysqltest to be able to handle connect() statements for which
  error is expected.
  
  - Added replace_dynstr_append() utility function.
  - added connect_n_handle_errors() function which connects with server
    without retries and handles errors as if "connect" was usual
    statement.
  - do_connect(): added ability to handle connects which are expected
    to return an error.
  - run_query_normal(): Moved all expected-error-handling code to separate
    normal_handle_error()/normal_handle_no_error() functions to be able
    to reuse them in connect_n_handle_errors().
mysql-test/r/grant.result:
  Fixed test results since one more column to mysql.user was added.
mysql-test/r/system_mysql_db.result:
  Fixed test results since one more column to mysql.user was added.
scripts/mysql_create_system_tables.sh:
  Added max_user_connections column to mysql.user table for storing
  new maximal concurrent connections per account limit.
scripts/mysql_fix_privilege_tables.sql:
  Added max_user_connections column to mysql.user table for storing
  new maximal concurrent connections per account limit.
sql/lex.h:
  Added MAX_USER_CONNECTIONS symbol used for specifying
  maximum number of concurrent connections per account.
sql/mysql_priv.h:
  Added declaration of opt_old_style_user_limits variable which is defined
  in sql/mysqld.cc used in sql/sql_parse.cc.
sql/mysqld.cc:
  Added "old-style-user-limits" option which forces user limits to behave
  in old way i.e. to be counted per user/host pair instead of per account.
  Added comment describing mqh_used variable.
sql/set_var.cc:
  Added sys_var_max_user_conn class which implements support for the new 
  behavior of max_user_connections variable. Now the global instance of
  this variable holds default maximum number of concurrent connections per
  account (as it was before) and the session instance gives read-only
  access to account-specific version of this limit.
sql/set_var.h:
  Added sys_var_max_user_conn class which implements support for the new 
  behavior of max_user_connections variable. Now the global instance of
  this variable holds default maximum number of concurrent connections per
  account (as it was before) and the session instance gives read-only
  access to account-specific version of this limit.
sql/sql_acl.cc:
  Added support for account-specific MAX_USER_CONNECTIONS limit.
  Tweaked USER_RESOURCES and their handling for better clarity.
sql/sql_parse.cc:
  Added support for account-specific MAX_USER_CONNECTIONS (maximum number
  of concurrent connections per account) limit. Changed default behavior
  of all user limits to be per account instead of per user+host.
  '--old-style-user-limits' option was added to enable the old behavior.
  Made maximum number of connections per hour to be independant on the
  value of global max_user_connections variable.
sql/sql_yacc.yy:
  Added support of new MAX_USER_CONNECTIONS limit to grammar.
  Renamed USER_RESOURCES::connections member to conn_per_hour and bits
  member to specified_limits. Also enum is used instead of naked numbers
  when we are working with specified_limits.
sql/structs.h:
  USER_RESOURCES struct:
   - Added user_conn member to store the maximum number of concurrent 
     connections for an account. Renamed connections member to 
     conn_per_hour for less ambiguity.
   - Renamed member 'bits' to 'specified_limits' for the sake of clarity.
     The member was used as a flag indicating which limits were mentioned
     in GRANT clause.
   - Added comments.
  USER_CONN struct:
   - Removed unused user_len member.
   - Added comments.

1 files changed, 153 insertions, 0 deletions

diff --git a/mysql-test/t/user_limits.test b/mysql-test/t/user_limits.test
new file mode 100644
index 00000000000..e911e1741c9
--- /dev/null
+++ b/mysql-test/t/user_limits.test
@@ -0,0 +1,153 @@
+#
+# Test behavior of various per-account limits (aka quotas)
+#
+
+# Prepare play-ground 
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+create table t1 (i int);
+# Just be sure that nothing will bother us
+delete from mysql.user where user like 'mysqltest\_%';
+delete from mysql.db where user like 'mysqltest\_%';
+delete from mysql.tables_priv where user like 'mysqltest\_%';
+delete from mysql.columns_priv where user like 'mysqltest\_%';
+flush privileges;
+
+# Test of MAX_QUERIES_PER_HOUR limit
+grant usage on *.* to mysqltest_1@localhost with max_queries_per_hour 2;
+connect (mqph, localhost, mysqltest_1,,);
+connection mqph;
+select * from t1;
+select * from t1;
+--error 1226
+select * from t1;
+connect (mqph2, localhost, mysqltest_1,,);
+connection mqph2;
+--error 1226
+select * from t1;
+# cleanup
+connection default;
+drop user mysqltest_1@localhost;
+disconnect mqph;
+disconnect mqph2;
+
+# Test of MAX_UPDATES_PER_HOUR limit
+grant usage on *.* to mysqltest_1@localhost with max_updates_per_hour 2;
+connect (muph, localhost, mysqltest_1,,);
+connection muph;
+select * from t1;
+select * from t1;
+select * from t1;
+delete from t1;
+delete from t1;
+--error 1226
+delete from t1;
+select * from t1;
+connect (muph2, localhost, mysqltest_1,,);
+connection muph2;
+--error 1226
+delete from t1;
+select * from t1;
+# Cleanup
+connection default;
+drop user mysqltest_1@localhost;
+disconnect muph;
+disconnect muph2;
+
+# Test of MAX_CONNECTIONS_PER_HOUR limit
+grant usage on *.* to mysqltest_1@localhost with max_connections_per_hour 2;
+connect (mcph1, localhost, mysqltest_1,,);
+connection mcph1;
+select * from t1;
+connect (mcph2, localhost, mysqltest_1,,);
+connection mcph2;
+select * from t1;
+--replace_result $MASTER_MYPORT MYSQL_PORT $MASTER_MYSOCK MYSQL_SOCK
+--error 1226
+connect (mcph3, localhost, mysqltest_1,,);
+# Old connection is still ok
+select * from t1;
+# Let us try to close old connections and try again. This will also test that
+# counters are not thrown away if there are no connections for this user.
+disconnect mcph1;
+disconnect mcph2;
+--error 1226
+connect (mcph3, localhost, mysqltest_1,,);
+# Cleanup
+connection default;
+drop user mysqltest_1@localhost;
+
+# Test of MAX_USER_CONNECTIONS limit
+# We need this to reset internal mqh_used variable
+flush privileges;
+grant usage on *.* to mysqltest_1@localhost with max_user_connections 2;
+connect (muc1, localhost, mysqltest_1,,);
+connection muc1;
+select * from t1;
+connect (muc2, localhost, mysqltest_1,,);
+connection muc2;
+select * from t1;
+--replace_result $MASTER_MYPORT MYSQL_PORT $MASTER_MYSOCK MYSQL_SOCK
+--error 1226
+connect (muc3, localhost, mysqltest_1,,);
+# Closing of one of connections should help
+disconnect muc1;
+connect (muc3, localhost, mysqltest_1,,);
+select * from t1;
+# Changing of limit should also help (and immediately) 
+connection default;
+grant usage on *.* to mysqltest_1@localhost with max_user_connections 3;
+connect (muc4, localhost, mysqltest_1,,);
+connection muc4;
+select * from t1;
+--replace_result $MASTER_MYPORT MYSQL_PORT $MASTER_MYSOCK MYSQL_SOCK
+--error 1226
+connect (muc5, localhost, mysqltest_1,,);
+# Clean up
+connection default;
+disconnect muc2;
+disconnect muc3;
+disconnect muc4;
+drop user mysqltest_1@localhost;
+
+# Now let us test interaction between global and per-account
+# max_user_connections limits
+select @@session.max_user_connections, @@global.max_user_connections;
+# Local max_user_connections variable can't be set directly
+# since this limit is per-account
+--error 1229
+set session max_user_connections= 2; 
+# But it is ok to set global max_user_connections
+set global max_user_connections= 2; 
+select @@session.max_user_connections, @@global.max_user_connections;
+# Let us check that global limit works
+grant usage on *.* to mysqltest_1@localhost;
+connect (muca1, localhost, mysqltest_1,,);
+connection muca1;
+select @@session.max_user_connections, @@global.max_user_connections;
+connect (muca2, localhost, mysqltest_1,,);
+connection muca2;
+select * from t1;
+--replace_result $MASTER_MYPORT MYSQL_PORT $MASTER_MYSOCK MYSQL_SOCK
+--error 1203
+connect (muca3, localhost, mysqltest_1,,);
+# Now we are testing that per-account limit prevails over gloabl limit
+connection default;
+grant usage on *.* to mysqltest_1@localhost with max_user_connections 3;
+connect (muca3, localhost, mysqltest_1,,);
+connection muca3;
+select @@session.max_user_connections, @@global.max_user_connections;
+--replace_result $MASTER_MYPORT MYSQL_PORT $MASTER_MYSOCK MYSQL_SOCK
+--error 1226
+connect (muca4, localhost, mysqltest_1,,);
+# Cleanup
+connection default;
+disconnect muca1;
+disconnect muca2;
+disconnect muca3;
+set global max_user_connections= 0; 
+drop user mysqltest_1@localhost;
+
+# Final cleanup
+drop table t1;