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Initial threadpool implementation for MariaDB 5.5

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This commit is contained in:
Vladislav Vaintroub
2011-12-08 19:17:49 +01:00
parent 5e7b949e61
commit e91bbca5fb
24 changed files with 2553 additions and 190 deletions
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37
sql/sql_class.cc
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@@ -1536,35 +1536,10 @@ void THD::awake(killed_state state_to_set)
if (state_to_set >= KILL_CONNECTION || state_to_set == NOT_KILLED)
{
#ifdef SIGNAL_WITH_VIO_CLOSE
if (this != current_thd)
if (this != current_thd)
{
/*
Before sending a signal, let's close the socket of the thread
that is being killed ("this", which is not the current thread).
This is to make sure it does not block if the signal is lost.
This needs to be done only on platforms where signals are not
a reliable interruption mechanism.
Note that the downside of this mechanism is that we could close
the connection while "this" target thread is in the middle of
sending a result to the application, thus violating the client-
server protocol.
On the other hand, without closing the socket we have a race
condition. If "this" target thread passes the check of
thd->killed, and then the current thread runs through
THD::awake(), sets the 'killed' flag and completes the
signaling, and then the target thread runs into read(), it will
block on the socket. As a result of the discussions around
Bug#37780, it has been decided that we accept the race
condition. A second KILL awakes the target from read().
If we are killing ourselves, we know that we are not blocked.
We also know that we will check thd->killed before we go for
reading the next statement.
*/
close_active_vio();
if(active_vio)
vio_shutdown(active_vio, SHUT_RDWR);
}
#endif
@@ -1668,7 +1643,7 @@ void THD::disconnect()
/* Disconnect even if a active vio is not associated. */
if (net.vio != vio)
vio_close(net.vio);
vio_close(net.vio);
mysql_mutex_unlock(&LOCK_thd_data);
}
@@ -1740,6 +1715,10 @@ bool THD::store_globals()
mysys_var->stack_ends_here= thread_stack + // for consistency, see libevent_thread_proc
STACK_DIRECTION * (long)my_thread_stack_size;
#ifdef _WIN32
if (net.vio)
net.vio->thread_id= real_id; /* Required to support IO cancelation on XP */
#endif
/*
We have to call thr_lock_info_init() again here as THD may have been
created in another thread