maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Nirbhay!

On Aug 19, Nirbhay Choubey wrote:
> revision-id: 8bf23efc914f18c687067e9314cadf4f36a85eec
> parent(s): 71d1f35847a575239deff856590bf6f13afd74ed
> committer: Nirbhay Choubey
> branch nick: 5.5-galera.b8208
> timestamp: 2015-08-19 17:17:56 -0400
> message:
> 
> MDEV-8208: Sporadic SEGFAULT on startup

A couple of questions:

> diff --git a/sql/mysqld.cc b/sql/mysqld.cc
> index 2008fc5..4c05999 100644
> --- a/sql/mysqld.cc
> +++ b/sql/mysqld.cc
> @@ -4584,6 +4579,29 @@ static int init_server_components()
>    }
>    plugins_are_initialized= TRUE;  /* Don't separate from init function */
>  
> +#ifdef WITH_WSREP
> +  /* Wait for wsrep threads to get created. */
> +  if (wsrep_creating_startup_threads == 1) {
> +    mysql_mutex_lock(&LOCK_thread_count);
> +    while (wsrep_running_threads < 2)
> +    {
> +      mysql_cond_wait(&COND_thread_count, &LOCK_thread_count);
> +    }
> +
> +    /* Now is the time to initialize threads for queries. */
> +    THD *tmp;
> +    I_List_iterator<THD> it(threads);
> +    while ((tmp= it++))
> +      if (tmp->wsrep_applier == true)
> +        tmp->init_for_queries();

Do you really need to iterate over all THD's? There is only one applier
thread, right? And it's THD is not stored anywhere, only in the global
list?

> +    mysql_mutex_unlock(&LOCK_thread_count);
> +  }
> +#endif
> +
>    have_csv= plugin_status(STRING_WITH_LEN("csv"),
>                            MYSQL_STORAGE_ENGINE_PLUGIN);
>    have_ndbcluster= plugin_status(STRING_WITH_LEN("ndbcluster"),
> @@ -4890,12 +4902,21 @@ pthread_handler_t start_wsrep_THD(void *arg)
>    //thd->version= refresh_version;
>    thd->proc_info= 0;
>    thd->command= COM_SLEEP;
> -  thd->set_time();
> -  thd->init_for_queries();
> +
> +  if (plugins_are_initialized)
> +  {
> +    thd->init_for_queries();
> +  }

What happens if plugins are not initialized yet?
thd->init_for_queries() will be done in that THD loop above?
In that case why do you need to do it here?

Regards,
Sergei