Fix for Bug#33507: Event scheduler creates more threads
than max_connections -- which results in user lockout. The problem was that the variable thread_count that contains the number of active threads was interpreted as a number of active connections. The fix is to introduce a new counter for active connections.
This commit is contained in:
anozdrin/alik@quad.
parent
e57679c204
commit
18125abf93
@ -115,3 +115,61 @@ create temporary table t2(id integer not null auto_increment primary key);
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set @id := 1;
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delete from t1 where id like @id;
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drop table t1;
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# ------------------------------------------------------------------
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# -- End of 4.1 tests
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# ------------------------------------------------------------------
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# -- Bug#33507: Event scheduler creates more threads than max_connections
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# -- which results in user lockout.
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GRANT USAGE ON *.* TO mysqltest_u1@localhost;
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SET GLOBAL max_connections = 3;
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SET GLOBAL event_scheduler = ON;
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# -- Waiting for old connections to close...
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# -- Disconnecting default connection...
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# -- Check that we allow exactly three user connections, no matter how
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# -- many threads are running.
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# -- Connecting (1)...
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# -- Waiting for root connection to close...
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# -- Connecting (2)...
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# -- Connecting (3)...
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# -- Connecting (4)...
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ERROR 08004: Too many connections
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# -- Waiting for the last connection to close...
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# -- Check that we allow one extra SUPER-user connection.
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# -- Connecting super (1)...
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# -- Connecting super (2)...
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ERROR 00000: Too many connections
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SELECT user FROM information_schema.processlist ORDER BY id;
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user
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event_scheduler
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mysqltest_u1
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mysqltest_u1
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mysqltest_u1
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root
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# -- Resetting variables...
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SET GLOBAL max_connections = 151;
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SET GLOBAL event_scheduler = OFF;
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# -- That's it. Closing connections...
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# -- Restoring default connection...
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# -- End of Bug#33507.
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# ------------------------------------------------------------------
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# -- End of 5.1 tests
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# ------------------------------------------------------------------
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@ -102,4 +102,129 @@ disconnect con7;
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connection default;
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drop table t1;
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# End of 4.1 tests
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--disconnect con1
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--disconnect con2
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--disconnect con3
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--disconnect con4
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--disconnect con5
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--disconnect con6
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--disconnect con10
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--echo # ------------------------------------------------------------------
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--echo # -- End of 4.1 tests
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--echo # ------------------------------------------------------------------
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--echo
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--echo # -- Bug#33507: Event scheduler creates more threads than max_connections
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--echo # -- which results in user lockout.
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--echo
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GRANT USAGE ON *.* TO mysqltest_u1@localhost;
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# NOTE: if the test case fails sporadically due to spurious connections,
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# consider disabling all users.
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--echo
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let $saved_max_connections = `SELECT @@global.max_connections`;
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SET GLOBAL max_connections = 3;
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SET GLOBAL event_scheduler = ON;
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--echo
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--echo # -- Waiting for old connections to close...
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let $wait_condition =
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SELECT COUNT(*) = 1
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FROM information_schema.processlist
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WHERE db = 'test';
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--source include/wait_condition.inc
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--echo
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let $wait_condition =
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SELECT COUNT(*) = 1
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FROM information_schema.processlist
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WHERE user = 'event_scheduler';
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--source include/wait_condition.inc
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--echo
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--echo # -- Disconnecting default connection...
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--disconnect default
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--echo
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--echo # -- Check that we allow exactly three user connections, no matter how
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--echo # -- many threads are running.
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--echo
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--echo # -- Connecting (1)...
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--connect (con_1,localhost,mysqltest_u1)
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--echo
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--echo # -- Waiting for root connection to close...
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let $wait_condition =
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SELECT COUNT(*) = 1
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FROM information_schema.processlist
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WHERE db = 'test';
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--source include/wait_condition.inc
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--echo
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--echo # -- Connecting (2)...
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--connect (con_2,localhost,mysqltest_u1)
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--echo # -- Connecting (3)...
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--connect (con_3,localhost,mysqltest_u1)
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--echo # -- Connecting (4)...
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--disable_query_log
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--error ER_CON_COUNT_ERROR
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--connect (con_4,localhost,mysqltest_u1)
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--enable_query_log
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--echo
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--echo # -- Waiting for the last connection to close...
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let $wait_condition =
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SELECT COUNT(*) = 3
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FROM information_schema.processlist
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WHERE db = 'test';
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--source include/wait_condition.inc
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--echo
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--echo # -- Check that we allow one extra SUPER-user connection.
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--echo
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--echo # -- Connecting super (1)...
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--connect (con_super_1,localhost,root)
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--echo # -- Connecting super (2)...
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--disable_query_log
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--error ER_CON_COUNT_ERROR
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--connect (con_super_2,localhost,root)
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--enable_query_log
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--echo
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# Ensure that we have Event Scheduler thread, 3 ordinary user connections and
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# one extra super-user connection.
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SELECT user FROM information_schema.processlist ORDER BY id;
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--echo
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--echo # -- Resetting variables...
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--eval SET GLOBAL max_connections = $saved_max_connections
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SET GLOBAL event_scheduler = OFF;
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--echo
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--echo # -- That's it. Closing connections...
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--disconnect con_1
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--disconnect con_2
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--disconnect con_super_1
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--echo
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--echo # -- Restoring default connection...
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--connect (default,localhost,root,,test)
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--echo
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--echo # -- End of Bug#33507.
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--echo
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--echo # ------------------------------------------------------------------
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--echo # -- End of 5.1 tests
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--echo # ------------------------------------------------------------------
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@ -974,8 +974,6 @@ void time_out_user_resource_limits(THD *thd, USER_CONN *uc);
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void decrease_user_connections(USER_CONN *uc);
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void thd_init_client_charset(THD *thd, uint cs_number);
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bool setup_connection_thread_globals(THD *thd);
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bool login_connection(THD *thd);
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void end_connection(THD *thd);
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bool mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create, bool silent);
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bool mysql_alter_db(THD *thd, const char *db, HA_CREATE_INFO *create);
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@ -1895,6 +1893,7 @@ extern bool opt_disable_networking, opt_skip_show_db;
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extern my_bool opt_character_set_client_handshake;
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extern bool volatile abort_loop, shutdown_in_progress;
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extern uint volatile thread_count, thread_running, global_read_lock;
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extern uint connection_count;
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extern my_bool opt_sql_bin_update, opt_safe_user_create, opt_no_mix_types;
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extern my_bool opt_safe_show_db, opt_local_infile, opt_myisam_use_mmap;
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extern my_bool opt_slave_compressed_protocol, use_temp_pool;
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@ -1933,7 +1932,7 @@ extern pthread_mutex_t LOCK_mysql_create_db,LOCK_Acl,LOCK_open, LOCK_lock_db,
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LOCK_slave_list, LOCK_active_mi, LOCK_manager, LOCK_global_read_lock,
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LOCK_global_system_variables, LOCK_user_conn,
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LOCK_prepared_stmt_count,
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LOCK_bytes_sent, LOCK_bytes_received;
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LOCK_bytes_sent, LOCK_bytes_received, LOCK_connection_count;
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#ifdef HAVE_OPENSSL
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extern pthread_mutex_t LOCK_des_key_file;
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#endif
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@ -584,7 +584,8 @@ pthread_mutex_t LOCK_mysql_create_db, LOCK_Acl, LOCK_open, LOCK_thread_count,
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LOCK_delayed_insert, LOCK_delayed_status, LOCK_delayed_create,
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LOCK_crypt, LOCK_bytes_sent, LOCK_bytes_received,
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LOCK_global_system_variables,
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LOCK_user_conn, LOCK_slave_list, LOCK_active_mi;
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LOCK_user_conn, LOCK_slave_list, LOCK_active_mi,
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LOCK_connection_count;
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/**
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The below lock protects access to two global server variables:
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max_prepared_stmt_count and prepared_stmt_count. These variables
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@ -720,6 +721,11 @@ char *des_key_file;
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struct st_VioSSLFd *ssl_acceptor_fd;
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#endif /* HAVE_OPENSSL */
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/**
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Number of currently active user connections. The variable is protected by
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LOCK_connection_count.
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*/
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uint connection_count= 0;
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/* Function declarations */
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@ -1341,6 +1347,7 @@ static void clean_up_mutexes()
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(void) pthread_mutex_destroy(&LOCK_bytes_sent);
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(void) pthread_mutex_destroy(&LOCK_bytes_received);
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(void) pthread_mutex_destroy(&LOCK_user_conn);
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(void) pthread_mutex_destroy(&LOCK_connection_count);
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Events::destroy_mutexes();
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#ifdef HAVE_OPENSSL
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(void) pthread_mutex_destroy(&LOCK_des_key_file);
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@ -1783,6 +1790,11 @@ void unlink_thd(THD *thd)
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DBUG_ENTER("unlink_thd");
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DBUG_PRINT("enter", ("thd: 0x%lx", (long) thd));
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thd->cleanup();
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pthread_mutex_lock(&LOCK_connection_count);
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--connection_count;
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pthread_mutex_unlock(&LOCK_connection_count);
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(void) pthread_mutex_lock(&LOCK_thread_count);
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thread_count--;
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delete thd;
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@ -3453,6 +3465,7 @@ static int init_thread_environment()
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(void) pthread_mutex_init(&LOCK_global_read_lock, MY_MUTEX_INIT_FAST);
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(void) pthread_mutex_init(&LOCK_prepared_stmt_count, MY_MUTEX_INIT_FAST);
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(void) pthread_mutex_init(&LOCK_uuid_generator, MY_MUTEX_INIT_FAST);
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(void) pthread_mutex_init(&LOCK_connection_count, MY_MUTEX_INIT_FAST);
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#ifdef HAVE_OPENSSL
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(void) pthread_mutex_init(&LOCK_des_key_file,MY_MUTEX_INIT_FAST);
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#ifndef HAVE_YASSL
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@ -4700,6 +4713,11 @@ void create_thread_to_handle_connection(THD *thd)
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thread_count--;
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thd->killed= THD::KILL_CONNECTION; // Safety
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(void) pthread_mutex_unlock(&LOCK_thread_count);
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pthread_mutex_lock(&LOCK_connection_count);
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--connection_count;
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pthread_mutex_unlock(&LOCK_connection_count);
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statistic_increment(aborted_connects,&LOCK_status);
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/* Can't use my_error() since store_globals has not been called. */
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my_snprintf(error_message_buff, sizeof(error_message_buff),
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@ -4739,15 +4757,31 @@ static void create_new_thread(THD *thd)
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if (protocol_version > 9)
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net->return_errno=1;
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/* don't allow too many connections */
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if (thread_count - delayed_insert_threads >= max_connections+1 || abort_loop)
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/*
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Don't allow too many connections. We roughly check here that we allow
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only (max_connections + 1) connections.
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*/
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pthread_mutex_lock(&LOCK_connection_count);
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if (connection_count >= max_connections + 1 || abort_loop)
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{
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pthread_mutex_unlock(&LOCK_connection_count);
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DBUG_PRINT("error",("Too many connections"));
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close_connection(thd, ER_CON_COUNT_ERROR, 1);
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delete thd;
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DBUG_VOID_RETURN;
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}
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++connection_count;
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pthread_mutex_unlock(&LOCK_connection_count);
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/* Start a new thread to handle connection. */
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pthread_mutex_lock(&LOCK_thread_count);
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/*
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The initialization of thread_id is done in create_embedded_thd() for
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the embedded library.
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@ -4755,13 +4789,13 @@ static void create_new_thread(THD *thd)
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*/
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thd->thread_id= thd->variables.pseudo_thread_id= thread_id++;
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/* Start a new thread to handle connection */
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thread_count++;
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if (thread_count - delayed_insert_threads > max_used_connections)
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max_used_connections= thread_count - delayed_insert_threads;
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thread_scheduler.add_connection(thd);
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DBUG_VOID_RETURN;
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}
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#endif /* EMBEDDED_LIBRARY */
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@ -402,10 +402,11 @@ check_user(THD *thd, enum enum_server_command command,
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if (check_count)
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{
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VOID(pthread_mutex_lock(&LOCK_thread_count));
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bool count_ok= thread_count <= max_connections + delayed_insert_threads
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|| (thd->main_security_ctx.master_access & SUPER_ACL);
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VOID(pthread_mutex_unlock(&LOCK_thread_count));
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pthread_mutex_lock(&LOCK_connection_count);
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bool count_ok= connection_count <= max_connections ||
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(thd->main_security_ctx.master_access & SUPER_ACL);
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VOID(pthread_mutex_unlock(&LOCK_connection_count));
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if (!count_ok)
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{ // too many connections
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my_error(ER_CON_COUNT_ERROR, MYF(0));
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@ -930,7 +931,7 @@ bool setup_connection_thread_globals(THD *thd)
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*/
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bool login_connection(THD *thd)
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static bool login_connection(THD *thd)
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{
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NET *net= &thd->net;
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int error;
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@ -968,7 +969,7 @@ bool login_connection(THD *thd)
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This mainly updates status variables
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*/
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void end_connection(THD *thd)
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static void end_connection(THD *thd)
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{
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NET *net= &thd->net;
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plugin_thdvar_cleanup(thd);
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