Hi, 김경남! You need to call my_thread_init() as early as possible in your new thread. And my_thread_end() Just before your thread ends. Regards, Sergei On Mar 30, 김경남 wrote:
Hi, I'm writing mariadb daemon type plugin. I hava a question.
In a daemon thread, I want to use THD instance. for example,
------------------------------------------------------------------------ ----------- class THD; static int plugin_init() { ... pthread_create(&id,&attr,my_func,...); }
void my_func(void* p) { THD* thd = new THD; thd->thread_stack= (char*) &thd; thd->store_globals(); tables.init_one_table("performance_schema", 18, "events_statements_current", 25, "events_statements_current", TL_READ); open_and_lock_tables(thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT); ... }
------------------------------------------------------------------------ -------------------- but In my_func(), new THD cause error. I guess thread problem.
So I moved that code to plugin_init() for test as below
-------------------------------------------------------------- class THD; static int plugin_init() { ... pthread_create(&id,&attr,my_func,...); THD* thd = new THD; thd->thread_stack= (char*) &thd; thd->store_globals(); tables.init_one_table("performance_schema", 18, "events_statements_current", 25, "events_statements_current", TL_READ); open_and_lock_tables(thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT); ... } ------------------------------------------------------------------------ ----- and then there is no problem. but I need a daemon thread. I think that the reason of this error is assertion of thread. So I changed my code as below.
------------------------------------------------------------------------ --------- class THD; THD* thd; static int plugin_init() { ... pthread_create(&id,&attr,my_func,...); THD* thd = new THD; // moved here from my_func() for avoiding error. }
void my_func(void* p) { thd->thread_stack= (char*) &thd; thd->store_globals(); tables.init_one_table("performance_schema", 18, "events_statements_current", 25, "events_statements_current", TL_READ); open_and_lock_tables(thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT); ...
} ------------------------------------------------------------------------ ----------------- At this time, thd->store_globals() cause error. In sql_class.cc , mysys_var->id= thread_id cause error because mysys_var is null.
Let me know how to use THD instance in daemon thread.
Regards, Kyungnam