Re: Out of threads

[christos%astron.com@localhost (Christos Zoulas)]

In article <1m40q40.be9cjllegby3M%manu%netbsd.org@localhost>,
Emmanuel Dreyfus <manu%netbsd.org@localhost> wrote:
>Hello
>
>I have a problem with Apache, that sometimes horribly dies with this
>message:
>Can't initialize threads: error 35
>
>The strings is from libmysqlclient. In MySQL source, we have:
>mysql-5.6.23/mysys/my_thr_init.c
>  if ((pth_ret= pthread_key_create(&THR_KEY_mysys, NULL)) != 0)
>  {
>    fprintf(stderr, "Can't initialize threads: error %d\n", pth_ret);
>    return 1; 
>  }
>
>In NetBSD, src/lib/libpthread/pthread_tsd.c
>        for (i = nextkey; i < PTHREAD_KEYS_MAX; i++)
>                if (pthread__tsd_alloc[i] == NULL)
>                        break;
>
>        if (i == PTHREAD_KEYS_MAX) {
>                /* 2. If that didn't work, search from the start
>                 *    of the list back to "nextkey".
>                 */
>                for (i = 0; i < nextkey; i++)
>                        if (pthread__tsd_alloc[i] == NULL)
>                                break;
>
>                if (i == nextkey) {
>                        /* If we didn't find one here, there isn't one
>                         * to be found.
>                         */
>                        pthread_mutex_unlock(&tsd_mutex);
>                        return EAGAIN;
>
>We hit a hardcoded value here, which is set to 256 in <limits.h>. Anyone
>encountered this? Is there other workarounds than rebuilding libpthread
>with a higher PTHREAD_KEYS_MAX? In an ideal world, we could throttle on
>failure, instead of exitting.

The throttling needs to be done by the application; we return EAGAIN.
I think you need to compile with a larger PTHREAD_KEYS_MAX. Perhaps
we can make this more flexible by dynamically allocating the array,
so one does not need to recompile (and provide PTHREAD_USER_KEYS_MAX
like: http://docstore.mik.ua/manuals/hp-ux/en/B2355-60130/pthread_key_create.3T.html).

christos