mysql-show_slave_status_nolock.patch

   1 # name       : show_slave_status_nolock.patch
   2 # introduced : 12
   3 # maintainer : Oleg
   4 #
   5 #!!! notice !!!
   6 # Any small change to this file in the main branch
   7 # should be done or reviewed by the maintainer!
   8 --- /dev/null
   9 +++ b/patch_info/show_slave_status_nolock.patch
  10 @@ -0,0 +1,6 @@
  11 +File=show_slave_status_nolock.patch
  12 +Name= SHOW SLAVE STATUS NOLOCK
  13 +Version=1.0
  14 +Author=Percona <info@percona.com>
  15 +License=GPL
  16 +Comment= Implement SHOW SLAVE STATUS without lock (STOP SLAVE lock the same mutex what lock SHOW SLAVE STATUS)
  17 --- a/sql/lex.h
  18 +++ b/sql/lex.h
  19 @@ -370,6 +370,7 @@
  20    { "NONE",            SYM(NONE_SYM)},
  21    { "NOT",             SYM(NOT_SYM)},
  22    { "NO_WRITE_TO_BINLOG",  SYM(NO_WRITE_TO_BINLOG)},
  23 +  { "NOLOCK",           SYM(NOLOCK_SYM)},
  24    { "NULL",            SYM(NULL_SYM)},
  25    { "NUMERIC",         SYM(NUMERIC_SYM)},
  26    { "NVARCHAR",                SYM(NVARCHAR_SYM)},
  27 --- a/sql/mysqld.cc
  28 +++ b/sql/mysqld.cc
  29 @@ -3278,6 +3278,7 @@
  30    {"show_profiles",        (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_PROFILES]), SHOW_LONG_STATUS},
  31    {"show_slave_hosts",     (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_SLAVE_HOSTS]), SHOW_LONG_STATUS},
  32    {"show_slave_status",    (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_SLAVE_STAT]), SHOW_LONG_STATUS},
  33 +  {"show_slave_status_nolock", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_SLAVE_NOLOCK_STAT]), SHOW_LONG_STATUS},
  34    {"show_status",          (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_STATUS]), SHOW_LONG_STATUS},
  35    {"show_storage_engines", (char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_STORAGE_ENGINES]), SHOW_LONG_STATUS},
  36    {"show_table_statistics",(char*) offsetof(STATUS_VAR, com_stat[(uint) SQLCOM_SHOW_TABLE_STATS]), SHOW_LONG_STATUS},
  37 --- a/sql/sql_lex.h
  38 +++ b/sql/sql_lex.h
  39 @@ -121,7 +121,8 @@
  40    SQLCOM_ALTER_DB_UPGRADE, SQLCOM_SHOW_TEMPORARY_TABLES,
  41    SQLCOM_SHOW_PROFILE, SQLCOM_SHOW_PROFILES,
  42    SQLCOM_SHOW_PATCHES,
  43 -
  44 +  /* SHOW SLAVE STATUS NOLOCK */
  45 +  SQLCOM_SHOW_SLAVE_NOLOCK_STAT,
  46    /*
  47      When a command is added here, be sure it's also added in mysqld.cc
  48      in "struct show_var_st status_vars[]= {" ...
  49 --- a/sql/sql_parse.cc
  50 +++ b/sql/sql_parse.cc
  51 @@ -330,6 +330,7 @@
  52    sql_command_flags[SQLCOM_SHOW_CREATE]=  CF_STATUS_COMMAND;
  53    sql_command_flags[SQLCOM_SHOW_MASTER_STAT]=  CF_STATUS_COMMAND;
  54    sql_command_flags[SQLCOM_SHOW_SLAVE_STAT]=  CF_STATUS_COMMAND;
  55 +  sql_command_flags[SQLCOM_SHOW_SLAVE_NOLOCK_STAT]=  CF_STATUS_COMMAND;
  56    sql_command_flags[SQLCOM_SHOW_CREATE_PROC]=  CF_STATUS_COMMAND;
  57    sql_command_flags[SQLCOM_SHOW_CREATE_FUNC]=  CF_STATUS_COMMAND;
  58    sql_command_flags[SQLCOM_SHOW_CREATE_TRIGGER]=  CF_STATUS_COMMAND;
  59 @@ -2596,12 +2597,17 @@
  60      pthread_mutex_unlock(&LOCK_active_mi);
  61      break;
  62    }
  63 +  case SQLCOM_SHOW_SLAVE_NOLOCK_STAT:
  64    case SQLCOM_SHOW_SLAVE_STAT:
  65    {
  66      /* Accept one of two privileges */
  67      if (check_global_access(thd, SUPER_ACL | REPL_CLIENT_ACL))
  68        goto error;
  69 -    pthread_mutex_lock(&LOCK_active_mi);
  70 +    bool do_lock=SQLCOM_SHOW_SLAVE_NOLOCK_STAT != lex->sql_command;
  71 +    if(do_lock)
  72 +    {
  73 +      pthread_mutex_lock(&LOCK_active_mi);
  74 +    }
  75      if (active_mi != NULL)
  76      {
  77        res = show_master_info(thd, active_mi);
  78 @@ -2612,7 +2618,19 @@
  79                     WARN_NO_MASTER_INFO, ER(WARN_NO_MASTER_INFO));
  80        my_ok(thd);
  81      }
  82 -    pthread_mutex_unlock(&LOCK_active_mi);
  83 +    if(do_lock)
  84 +    {
  85 +      pthread_mutex_unlock(&LOCK_active_mi);
  86 +    }
  87 +    DBUG_EXECUTE_IF("after_show_slave_status",
  88 +                    {
  89 +                      const char act[]=
  90 +                        "now "
  91 +                        "signal signal.after_show_slave_status";
  92 +                      DBUG_ASSERT(opt_debug_sync_timeout > 0);
  93 +                      DBUG_ASSERT(!debug_sync_set_action(current_thd,
  94 +                                                         STRING_WITH_LEN(act)));
  95 +                    };);
  96      break;
  97    }
  98    case SQLCOM_SHOW_MASTER_STAT:
  99 --- a/sql/sql_yacc.yy
 100 +++ b/sql/sql_yacc.yy
 101 @@ -1175,6 +1175,7 @@
 102  %token  STARTS_SYM
 103  %token  START_SYM                     /* SQL-2003-R */
 104  %token  STATUS_SYM
 105 +%token  NOLOCK_SYM                    /* SHOW SLAVE STATUS NOLOCK */
 106  %token  STDDEV_SAMP_SYM               /* SQL-2003-N */
 107  %token  STD_SYM
 108  %token  STOP_SYM
 109 @@ -10387,6 +10388,11 @@
 110            {
 111              Lex->sql_command = SQLCOM_SHOW_SLAVE_STAT;
 112            }
 113 +       /* SHOW SLAVE STATUS NOLOCK */
 114 +        | SLAVE STATUS_SYM NOLOCK_SYM
 115 +          {
 116 +           Lex->sql_command = SQLCOM_SHOW_SLAVE_NOLOCK_STAT; //SQLCOM_SHOW_SLAVE_NOLOCK_STAT;
 117 +          }
 118          | CLIENT_STATS_SYM wild_and_where
 119            {
 120             LEX *lex= Lex;
 121 --- /dev/null
 122 +++ b/mysql-test/t/percona_show_slave_status_nolock.test
 123 @@ -0,0 +1,88 @@
 124 +--source include/master-slave.inc
 125 +--source include/have_debug_sync.inc
 126 +--source include/have_binlog_format_statement.inc
 127 +
 128 +--let $rpl_connection_name=slave_lock
 129 +--let $rpl_server_number=2
 130 +--source include/rpl_connect.inc
 131 +
 132 +--let $rpl_connection_name=slave_nolock
 133 +--let $rpl_server_number=2
 134 +--source include/rpl_connect.inc
 135 +
 136 +--let $show_statement= SHOW PROCESSLIST
 137 +--let $field= Info
 138 +
 139 +connection master;
 140 +--echo [master]
 141 +--disable_warnings
 142 +DROP TABLE IF EXISTS t;
 143 +--enable_warnings
 144 +CREATE TABLE t(id INT);
 145 +sync_slave_with_master;
 146 +
 147 +connection slave;
 148 +--echo [slave]
 149 +SET DEBUG_SYNC='RESET';
 150 +SET GLOBAL DEBUG="+d,after_mysql_insert";
 151 +SET GLOBAL DEBUG="+d,after_show_slave_status";
 152 +
 153 +connection master;
 154 +--echo [master]
 155 +INSERT INTO t VALUES(0);
 156 +
 157 +connection slave;
 158 +--echo [slave]
 159 +--let $condition= 'INSERT INTO t VALUES(0)'
 160 +--source include/wait_show_condition.inc
 161 +
 162 +--echo check 'SHOW SLAVE STATUS' and 'SHOW SLAVE STATUS NOLOCK' - both should work fine
 163 +--source include/percona_show_slave_status_nolock.inc
 164 +
 165 +connection master;
 166 +--echo [master]
 167 +INSERT INTO t VALUES(1);
 168 +
 169 +connection slave;
 170 +--echo [slave]
 171 +--let $condition= 'INSERT INTO t VALUES(1)'
 172 +--source include/wait_show_condition.inc
 173 +
 174 +--let $rpl_connection_name=slave_stop
 175 +--let $rpl_server_number=2
 176 +--source include/rpl_connect.inc
 177 +
 178 +connection slave_stop;
 179 +--echo [slave_stop]
 180 +send STOP SLAVE;
 181 +
 182 +connection slave;
 183 +--echo [slave]
 184 +--let $condition= 'STOP SLAVE'
 185 +--source include/wait_show_condition.inc
 186 +
 187 +--echo check 'SHOW SLAVE STATUS' and 'SHOW SLAVE STATUS NOLOCK' - just NOLOCK version should works fine
 188 +--source include/percona_show_slave_status_nolock.inc
 189 +
 190 +
 191 +connection slave_stop;
 192 +--echo [slave_stop]
 193 +reap;
 194 +--source include/wait_for_slave_to_stop.inc
 195 +START SLAVE;
 196 +--source include/wait_for_slave_to_start.inc
 197 +
 198 +connection master;
 199 +--echo [master]
 200 +SET DEBUG_SYNC='RESET';
 201 +
 202 +connection slave;
 203 +--echo [slave]
 204 +SET GLOBAL DEBUG='';
 205 +SET DEBUG_SYNC='RESET';
 206 +
 207 +connection master;
 208 +DROP TABLE t;
 209 +sync_slave_with_master;
 210 +
 211 +--source include/rpl_end.inc
 212 --- /dev/null
 213 +++ b/mysql-test/r/percona_show_slave_status_nolock.result
 214 @@ -0,0 +1,68 @@
 215 +include/master-slave.inc
 216 +[connection master]
 217 +include/rpl_connect.inc [creating slave_lock]
 218 +include/rpl_connect.inc [creating slave_nolock]
 219 +[master]
 220 +DROP TABLE IF EXISTS t;
 221 +CREATE TABLE t(id INT);
 222 +[slave]
 223 +SET DEBUG_SYNC='RESET';
 224 +SET GLOBAL DEBUG="+d,after_mysql_insert";
 225 +SET GLOBAL DEBUG="+d,after_show_slave_status";
 226 +[master]
 227 +INSERT INTO t VALUES(0);
 228 +[slave]
 229 +check 'SHOW SLAVE STATUS' and 'SHOW SLAVE STATUS NOLOCK' - both should work fine
 230 +
 231 +[slave_lock]
 232 +SHOW SLAVE STATUS;
 233 +SET DEBUG_SYNC='now WAIT_FOR signal.after_show_slave_status TIMEOUT 1';
 234 +SIGNAL after SHOW SLAVE STATUS is 'signal.after_show_slave_status'
 235 +[slave]
 236 +SET DEBUG_SYNC='now SIGNAL signal.empty';
 237 +[slave_nolock]
 238 +SHOW SLAVE STATUS NOLOCK;
 239 +SET DEBUG_SYNC='now WAIT_FOR signal.after_show_slave_status TIMEOUT 1';
 240 +# should be 'signal.after_show_slave_status'
 241 +SIGNAL after SHOW SLAVE STATUS NOLOCK is 'signal.after_show_slave_status'
 242 +[slave]
 243 +SET DEBUG_SYNC='now SIGNAL signal.continue';
 244 +[slave]
 245 +SET DEBUG_SYNC='now SIGNAL signal.empty';
 246 +
 247 +[master]
 248 +INSERT INTO t VALUES(1);
 249 +[slave]
 250 +include/rpl_connect.inc [creating slave_stop]
 251 +[slave_stop]
 252 +STOP SLAVE;
 253 +[slave]
 254 +check 'SHOW SLAVE STATUS' and 'SHOW SLAVE STATUS NOLOCK' - just NOLOCK version should works fine
 255 +
 256 +[slave_lock]
 257 +SHOW SLAVE STATUS;
 258 +SET DEBUG_SYNC='now WAIT_FOR signal.after_show_slave_status TIMEOUT 1';
 259 +SIGNAL after SHOW SLAVE STATUS is 'signal.empty'
 260 +[slave]
 261 +SET DEBUG_SYNC='now SIGNAL signal.empty';
 262 +[slave_nolock]
 263 +SHOW SLAVE STATUS NOLOCK;
 264 +SET DEBUG_SYNC='now WAIT_FOR signal.after_show_slave_status TIMEOUT 1';
 265 +# should be 'signal.after_show_slave_status'
 266 +SIGNAL after SHOW SLAVE STATUS NOLOCK is 'signal.after_show_slave_status'
 267 +[slave]
 268 +SET DEBUG_SYNC='now SIGNAL signal.continue';
 269 +[slave]
 270 +SET DEBUG_SYNC='now SIGNAL signal.empty';
 271 +
 272 +[slave_stop]
 273 +include/wait_for_slave_to_stop.inc
 274 +START SLAVE;
 275 +include/wait_for_slave_to_start.inc
 276 +[master]
 277 +SET DEBUG_SYNC='RESET';
 278 +[slave]
 279 +SET GLOBAL DEBUG='';
 280 +SET DEBUG_SYNC='RESET';
 281 +DROP TABLE t;
 282 +include/rpl_end.inc
 283 --- /dev/null
 284 +++ b/mysql-test/include/percona_show_slave_status_nolock.inc
 285 @@ -0,0 +1,56 @@
 286 +--echo
 287 +--disable_result_log
 288 +connection slave_lock;
 289 +--echo [slave_lock]
 290 +send SHOW SLAVE STATUS;
 291 +
 292 +connection slave;
 293 +--let $condition= 'SHOW SLAVE STATUS'
 294 +--source include/wait_show_condition.inc
 295 +
 296 +--disable_warnings
 297 +SET DEBUG_SYNC='now WAIT_FOR signal.after_show_slave_status TIMEOUT 1';
 298 +--enable_warnings
 299 +
 300 +--let current=`SELECT SUBSTR(Variable_value FROM 22) FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE Variable_name = 'DEBUG_SYNC'`
 301 +--echo SIGNAL after SHOW SLAVE STATUS is $current
 302 +
 303 +connection slave;
 304 +--echo [slave]
 305 +SET DEBUG_SYNC='now SIGNAL signal.empty';
 306 +
 307 +connection slave_nolock;
 308 +--echo [slave_nolock]
 309 +send SHOW SLAVE STATUS NOLOCK;
 310 +
 311 +connection slave;
 312 +--let $condition= 'SHOW SLAVE STATUS NOLOCK'
 313 +--source include/wait_show_condition.inc
 314 +
 315 +--disable_warnings
 316 +SET DEBUG_SYNC='now WAIT_FOR signal.after_show_slave_status TIMEOUT 1';
 317 +--enable_warnings
 318 +
 319 +--echo # should be 'signal.after_show_slave_status'
 320 +--let current=`SELECT SUBSTR(Variable_value FROM 22) FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE Variable_name = 'DEBUG_SYNC'`
 321 +--echo SIGNAL after SHOW SLAVE STATUS NOLOCK is $current
 322 +
 323 +connection slave;
 324 +--echo [slave]
 325 +SET DEBUG_SYNC='now SIGNAL signal.continue';
 326 +
 327 +connection slave_lock;
 328 +--disable_result_log
 329 +reap;
 330 +--enable_result_log
 331 +
 332 +connection slave_nolock;
 333 +--disable_result_log
 334 +reap;
 335 +--enable_result_log
 336 +
 337 +connection slave;
 338 +--echo [slave]
 339 +SET DEBUG_SYNC='now SIGNAL signal.empty';
 340 +--enable_result_log
 341 +--echo
 342 --- a/sql/slave.cc
 343 +++ b/sql/slave.cc
 344 @@ -1641,6 +1641,7 @@
 345
 346    if (mi->host[0])
 347    {
 348 +    bool do_lock=SQLCOM_SHOW_SLAVE_NOLOCK_STAT != thd->lex->sql_command;
 349      DBUG_PRINT("info",("host is set: '%s'", mi->host));
 350      String *packet= &thd->packet;
 351      protocol->prepare_for_resend();
 352 @@ -1649,9 +1650,15 @@
 353        slave_running can be accessed without run_lock but not other
 354        non-volotile members like mi->io_thd, which is guarded by the mutex.
 355      */
 356 -    pthread_mutex_lock(&mi->run_lock);
 357 +    if (do_lock)
 358 +    {
 359 +      pthread_mutex_lock(&mi->run_lock);
 360 +    }
 361      protocol->store(mi->io_thd ? mi->io_thd->proc_info : "", &my_charset_bin);
 362 -    pthread_mutex_unlock(&mi->run_lock);
 363 +    if (do_lock)
 364 +    {
 365 +      pthread_mutex_unlock(&mi->run_lock);
 366 +    }
 367
 368      pthread_mutex_lock(&mi->data_lock);
 369      pthread_mutex_lock(&mi->rli.data_lock);