Execute bootstrap in main thread

Bootstrap in a separate thread was introduced in 746f0b3b7 to workaround
OS/2 small stack size. OS/2 support was discontinued in 2006 and modern
operating systems have default stack size a few times larger than
default thread_stack and it is tunable.

Aim is to reduce usage of LOCK_thread_count and COND_thread_count.
Part of MDEV-15135.

sql/mysqld.cc

@@ -400,20 +400,6 @@ uint volatile global_disable_checkpoint;
 #if defined(_WIN32) && !defined(EMBEDDED_LIBRARY)
 ulong slow_start_timeout;
 #endif
-/*
-  True if the bootstrap thread is running. Protected by LOCK_start_thread.
-  Used in bootstrap() function to determine if the bootstrap thread
-  has completed. Note, that we can't use 'thread_count' instead,
-  since in 5.1, in presence of the Event Scheduler, there may be
-  event threads running in parallel, so it's impossible to know
-  what value of 'thread_count' is a sign of completion of the
-  bootstrap thread.
-
-  At the same time, we can't start the event scheduler after
-  bootstrap either, since we want to be able to process event-related
-  SQL commands in the init file and in --bootstrap mode.
-*/
-bool volatile in_bootstrap= FALSE;
 /**
    @brief 'grant_option' is used to indicate if privileges needs
    to be checked, in which case the lock, LOCK_grant, is used
@@ -663,7 +649,6 @@ Lt_creator lt_creator;
 Ge_creator ge_creator;
 Le_creator le_creator;
 
-MYSQL_FILE *bootstrap_file;
 int bootstrap_error;
 
 I_List<THD> threads;
@@ -736,7 +721,6 @@ mysql_mutex_t LOCK_thread_count;
   other threads.
 
   It also protects these variables:
-  in_bootstrap
   select_thread_in_use
   slave_init_thread_running
   check_temp_dir() call
@@ -1542,7 +1526,6 @@ void handle_connections_sockets();
 #endif
 
 pthread_handler_t kill_server_thread(void *arg);
-static void bootstrap(MYSQL_FILE *file);
 static bool read_init_file(char *file_name);
 pthread_handler_t handle_slave(void *arg);
 static void clean_up(bool print_message);
@@ -6320,54 +6303,6 @@ int mysqld_main(int argc, char **argv)
 #endif
 
 
-/**
-  Execute all commands from a file. Used by the mysql_install_db script to
-  create MySQL privilege tables without having to start a full MySQL server
-  and by read_init_file() if mysqld was started with the option --init-file.
-*/
-
-static void bootstrap(MYSQL_FILE *file)
-{
-  DBUG_ENTER("bootstrap");
-
-  THD *thd= new THD(next_thread_id());
-#ifdef WITH_WSREP
-  thd->variables.wsrep_on= 0;
-#endif
-  thd->bootstrap=1;
-  my_net_init(&thd->net,(st_vio*) 0, thd, MYF(0));
-  thd->max_client_packet_length= thd->net.max_packet;
-  thd->security_ctx->master_access= ~(ulong)0;
-  in_bootstrap= TRUE;
-
-  bootstrap_file=file;
-#ifndef EMBEDDED_LIBRARY			// TODO:  Enable this
-  int error;
-  if ((error= mysql_thread_create(key_thread_bootstrap,
-                                  &thd->real_id, &connection_attrib,
-                                  handle_bootstrap,
-                                  (void*) thd)))
-  {
-    sql_print_warning("Can't create thread to handle bootstrap (errno= %d)",
-                      error);
-    bootstrap_error=-1;
-    delete thd;
-    DBUG_VOID_RETURN;
-  }
-  /* Wait for thread to die */
-  mysql_mutex_lock(&LOCK_thread_count);
-  while (in_bootstrap)
-    mysql_cond_wait(&COND_thread_count, &LOCK_thread_count);
-  mysql_mutex_unlock(&LOCK_thread_count);
-#else
-  thd->mysql= 0;
-  do_handle_bootstrap(thd);
-#endif
-
-  DBUG_VOID_RETURN;
-}
-
-
 static bool read_init_file(char *file_name)
 {
   MYSQL_FILE *file;

sql/mysqld.h

@@ -128,7 +128,6 @@ extern bool opt_ignore_builtin_innodb;
 extern my_bool opt_character_set_client_handshake;
 extern my_bool debug_assert_on_not_freed_memory;
 extern bool volatile abort_loop;
-extern bool volatile in_bootstrap;
 extern uint connection_count;
 extern my_bool opt_safe_user_create;
 extern my_bool opt_safe_show_db, opt_local_infile, opt_myisam_use_mmap;
@@ -297,7 +296,6 @@ extern int mysqld_server_started, mysqld_server_initialized;
 extern "C" MYSQL_PLUGIN_IMPORT int orig_argc;
 extern "C" MYSQL_PLUGIN_IMPORT char **orig_argv;
 extern pthread_attr_t connection_attrib;
-extern MYSQL_FILE *bootstrap_file;
 extern my_bool old_mode;
 extern LEX_STRING opt_init_connect, opt_init_slave;
 extern int bootstrap_error;

sql/sql_acl.cc

@@ -3318,7 +3318,7 @@ static int check_alter_user(THD *thd, const char *host, const char *user)
 
   if (IF_WSREP((!WSREP(thd) || !thd->wsrep_applier), 1) &&
       !thd->slave_thread && !thd->security_ctx->priv_user[0] &&
-      !in_bootstrap)
+      !thd->bootstrap)
   {
     my_message(ER_PASSWORD_ANONYMOUS_USER,
                ER_THD(thd, ER_PASSWORD_ANONYMOUS_USER),

sql/sql_db.cc

@@ -882,7 +882,7 @@ mysql_rm_db_internal(THD *thd, const LEX_CSTRING *db, bool if_exists, bool silen
       lock_db_routines(thd, dbnorm))
     goto exit;
 
-  if (!in_bootstrap && !rm_mysql_schema)
+  if (!thd->bootstrap && !rm_mysql_schema)
   {
     for (table= tables; table; table= table->next_local)
     {

sql/sql_parse.cc

@@ -979,15 +979,28 @@ static char *fgets_fn(char *buffer, size_t size, fgets_input_t input, int *error
 }
 
 
-static void handle_bootstrap_impl(THD *thd)
+void bootstrap(MYSQL_FILE *file)
 {
-  MYSQL_FILE *file= bootstrap_file;
+  DBUG_ENTER("handle_bootstrap");
-  DBUG_ENTER("handle_bootstrap_impl");
+
+  THD *thd= new THD(next_thread_id());
+#ifdef WITH_WSREP
+  thd->variables.wsrep_on= 0;
+#endif
+  thd->bootstrap=1;
+  my_net_init(&thd->net,(st_vio*) 0, thd, MYF(0));
+  thd->max_client_packet_length= thd->net.max_packet;
+  thd->security_ctx->master_access= ~(ulong)0;
 
 #ifndef EMBEDDED_LIBRARY
-  pthread_detach_this_thread();
+  mysql_thread_set_psi_id(thd->thread_id);
+#else
+  thd->mysql= 0;
+#endif
+
+  /* The following must be called before DBUG_ENTER */
   thd->thread_stack= (char*) &thd;
-#endif /* EMBEDDED_LIBRARY */
+  thd->store_globals();
 
   thd->security_ctx->user= (char*) my_strdup("boot", MYF(MY_WME));
   thd->security_ctx->priv_user[0]= thd->security_ctx->priv_host[0]=
@@ -1095,56 +1108,8 @@ static void handle_bootstrap_impl(THD *thd)
     free_root(&thd->transaction.mem_root,MYF(MY_KEEP_PREALLOC));
     thd->lex->restore_set_statement_var();
   }
-
-  DBUG_VOID_RETURN;
-}
-
-
-/**
-  Execute commands from bootstrap_file.
-
-  Used when creating the initial grant tables.
-*/
-
-pthread_handler_t handle_bootstrap(void *arg)
-{
-  THD *thd=(THD*) arg;
-
-  mysql_thread_set_psi_id(thd->thread_id);
-
-  do_handle_bootstrap(thd);
-  return 0;
-}
-
-void do_handle_bootstrap(THD *thd)
-{
-  /* The following must be called before DBUG_ENTER */
-  thd->thread_stack= (char*) &thd;
-  if (my_thread_init() || thd->store_globals())
-  {
-#ifndef EMBEDDED_LIBRARY
-    close_connection(thd, ER_OUT_OF_RESOURCES);
-#endif
-    thd->fatal_error();
-    goto end;
-  }
-
-  handle_bootstrap_impl(thd);
-
-end:
   delete thd;
-
+  DBUG_VOID_RETURN;
-  mysql_mutex_lock(&LOCK_thread_count);
-  in_bootstrap = FALSE;
-  mysql_cond_broadcast(&COND_thread_count);
-  mysql_mutex_unlock(&LOCK_thread_count);
-
-#ifndef EMBEDDED_LIBRARY
-  my_thread_end();
-  pthread_exit(0);
-#endif
-
-  return;
 }
 
 

sql/sql_parse.h

@@ -99,10 +99,9 @@ void create_table_set_open_action_and_adjust_tables(LEX *lex);
 void mysql_init_multi_delete(LEX *lex);
 bool multi_delete_set_locks_and_link_aux_tables(LEX *lex);
 void create_table_set_open_action_and_adjust_tables(LEX *lex);
-pthread_handler_t handle_bootstrap(void *arg);
+void bootstrap(MYSQL_FILE *file);
 int mysql_execute_command(THD *thd);
 bool do_command(THD *thd);
-void do_handle_bootstrap(THD *thd);
 bool dispatch_command(enum enum_server_command command, THD *thd,
 		      char* packet, uint packet_length,
                       bool is_com_multi, bool is_next_command);

sql/sql_table.cc

@@ -2104,7 +2104,7 @@ bool mysql_rm_table(THD *thd,TABLE_LIST *tables, bool if_exists,
       }
     }
     /* We remove statistics for table last, after we have the DDL lock */
-    if (!in_bootstrap)
+    if (!thd->bootstrap)
     {
       for (table= tables; table; table= table->next_local)
       {