database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

manually merged

Browse Source
This commit is contained in:
serg@serg.mylan
2004-08-18 19:57:55 +02:00
parent 7c69afaf15 8ce92878a2
commit e1237cbc53
107 changed files with 995 additions and 258 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
sql/sql_class.cc
View File

@ -434,8 +434,18 @@ void THD::awake(bool prepare_to_die)
exits the cond in the time between read and broadcast, but that is
ok since all we want to do is to make the victim thread get out
of waiting on current_cond.
If we see a non-zero current_cond: it cannot be an old value (because
then exit_cond() should have run and it can't because we have mutex); so
it is the true value but maybe current_mutex is not yet non-zero (we're
in the middle of enter_cond() and there is a "memory order
inversion"). So we test the mutex too to not lock 0.
Note that there is a small chance we fail to kill. If victim has locked
current_mutex, and hasn't entered enter_cond(), then we don't know it's
going to wait on cond. Then victim goes into its cond "forever" (until
we issue a second KILL). True we have set its thd->killed but it may not
see it immediately and so may have time to reach the cond_wait().
*/
if (mysys_var->current_cond)
if (mysys_var->current_cond && mysys_var->current_mutex)
{
pthread_mutex_lock(mysys_var->current_mutex);
pthread_cond_broadcast(mysys_var->current_cond);