maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Jan!

This was good! Just a few questions, see below

On Oct 24, Jan Lindström wrote:
> revision-id: 6d0c1f3ae12 (mariadb-10.2.40-114-g6d0c1f3ae12)
> parent(s): 3153cc799e2
> author: Jan Lindström
> committer: Jan Lindström
> timestamp: 2021-10-22 07:02:39 +0300
> message:
> 
> MDEV-23328 Server hang due to Galera lock conflict resolution
...
> diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
> index 3e1f248b082..5d40106d0ad 100644
> --- a/sql/sql_parse.cc
> +++ b/sql/sql_parse.cc
> @@ -2159,6 +2159,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
>      }
>      DBUG_PRINT("quit",("Got shutdown command for level %u", level));
>      general_log_print(thd, command, NullS);
> +    DBUG_EXECUTE_IF("shutdown_unireg_abort", { unireg_abort(1); });

what's the point of this test?

>      my_eof(thd);
>      kill_mysql(thd);
>      error=TRUE;
> diff --git a/sql/wsrep_mysqld.cc b/sql/wsrep_mysqld.cc
> index e60100e2e90..7466654eead 100644
> --- a/sql/wsrep_mysqld.cc
> +++ b/sql/wsrep_mysqld.cc
> @@ -835,13 +835,25 @@ void wsrep_thr_init()
>    DBUG_VOID_RETURN;
>  }
>  
> +/* This is wrapper for wsrep_break_lock in thr_lock.c */
> +static int wsrep_thr_abort_thd(void *bf_thd_ptr, void *victim_thd_ptr, my_bool signal)

When is it called? Under what conditions?

> +{
> +  THD* victim_thd= (THD *) victim_thd_ptr;
> +  /* We need to lock THD::LOCK_thd_data to protect victim
> +  from concurrent usage or disconnect or delete. */
> +  mysql_mutex_lock(&victim_thd->LOCK_thd_data);
> +  int res= wsrep_abort_thd(bf_thd_ptr, victim_thd_ptr, signal);
> +  return res;
> +}
> +
> diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
> index 73b3625b6fd..56400264245 100644
> --- a/storage/innobase/handler/ha_innodb.cc
> +++ b/storage/innobase/handler/ha_innodb.cc
> @@ -19720,46 +19716,113 @@ wsrep_innobase_kill_one_trx(
> +/*******************************************************************
> +This function is used to kill one transaction in BF. */
> +void
> +wsrep_innobase_kill_one_trx(
> +	MYSQL_THD const bf_thd,
> +	const trx_t * const bf_trx,
> +	trx_t *victim_trx,
> +	my_bool signal)
> +{
> +	ut_ad(bf_thd);
> +	ut_ad(victim_trx);
> +	ut_ad(lock_mutex_own());
> +	ut_ad(trx_mutex_own(victim_trx));
> +
> +	DBUG_ENTER("wsrep_innobase_kill_one_trx");
> +	THD *thd= (THD *) victim_trx->mysql_thd;
> +
> +	/* Here we need to lock THD::LOCK_thd_data to protect from
> +	concurrent usage or disconnect or delete. */
> +	DEBUG_SYNC(bf_thd, "wsrep_before_BF_victim_lock");
> +	my_sleep(100000);

Eh? Forgot to remove after debugging?

> +	wsrep_thd_LOCK(thd);
> +	my_sleep(100000);

and here

> +	DEBUG_SYNC(bf_thd, "wsrep_after_BF_victim_lock");
> +

Regards,
Sergei
VP of MariaDB Server Engineering
and security@xxxxxxxxxxx