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mariadb/sql/event_queue.cc
Michael Widenius 32f81bab7d WL#3262 add mutex lock order checking to safemutex (also called safe_mutex_deadlock_detector) 
This writes a warning on stderr if one uses mutex in different order,
like if one in one case would lock mutex in the order A,B and in another case
would lock mutex in the order B,A
This is inspired by and loosely based on the LOCKDEP patch by Jonas
Wrong mutex order is either fixed or mutex are marked with MYF_NO_DEADLOCK_DETECTION
if used inconsistently (need to be fixed by server team)

KNOWN_BUGS.txt:
  Added information that one need to dump and restore Maria tables
include/hash.h:
  Added prototype function for walking over all elements in a hash
include/my_pthread.h:
  Added my_pthread_mutex_init() and my_pthread_mutex_lock(); These should be used if one wants to disable mutex order checking.
  Changed names of the nonposix mutex_init functions to not conflict with my_phread_mutex_init()
  Added and extended structures for mutex deadlock detection.
  New arguments to sage_mutex_init() and safe_mutex_lock() to allow one to disable mutex order checking.
  Added variable 'safe_mutex_deadlock_detector' to enable/disable deadlock detection for all pthread_mutex_init()
mysys/Makefile.am:
  Added cleaning of test files
  Added test_thr_mutex
mysys/hash.c:
  Added hash_iterate() to iterate over all elements in a hash
  More comments
mysys/my_init.c:
  Added calls to destory all mutex uses by mysys()
  Added waiting for threads to end before calling TERMINATE() to list not freed memory
mysys/my_pthread.c:
  Changed names to free my_pthread_mutex_init() for mutex-lock-order-checking
mysys/my_sleep.c:
  Fixed too long wait if using 1000000L as argument
mysys/my_thr_init.c:
  Mark THR_LOCK_threads and THR_LOCK_malloc to not have mutex deadlock detection.
  (We can't have it enabled for this as these are internal mutex used by the detector  
  Call my_thread_init() early as we need thread specific variables enabled for the following pthread_mutex_init()
  Move code to wait for threads to end to my_wait_for_other_threads_to_die()
  Don't destroy mutex and conditions unless all threads have died
  Added my_thread_destroy_mutex() to destroy all mutex used by the mysys thread system
  Name the thread specific mutex as "mysys_var->mutex"
  Added my_thread_var_mutex_in_use() to return pointer to mutex in use or 0 if thread variables are not initialized
mysys/mysys_priv.h:
  Added prototypes for functions used internally with mutex-wrong-usage detection
mysys/thr_mutex.c:
  Added runtime detection of mutex used in conflicting order
  See WL#3262 or test_thr_mutex.c for examples
  The base idea is for each mutex have two hashes:
  - mutex->locked_mutex points to all mutex used after this one
  - mutex->used_mutex points to all mutex which has this mutex in it's mutex->locked_mutex
  There is a wrong mutex order if any mutex currently locked before this mutex is in the mutex->locked_mutex hash
sql/event_queue.cc:
  Mark mutex used inconsistently (need to be fixed by server team)
sql/event_scheduler.cc:
  Declare the right order to take the mutex
sql/events.cc:
  Mark mutex used inconsistently (need to be fixed by server team)
sql/ha_ndbcluster_binlog.cc:
  Mark mutex used inconsistently (need to be fixed by server team)
sql/log.cc:
  Mark mutex used inconsistently (need to be fixed by server team)
sql/mysqld.cc:
  Use pthread_mutex_trylock instead of pthread_mutex_unlock() when sending kill signal to thread
  This is needed to avoid wrong mutex order as normally one takes 'current_mutex' before mysys_var->mutex.
  Added call to free sp cache.
  Add destruction of LOCK_server_started and COND_server_started.
  Added register_mutex_order() function to register in which order mutex should be taken
  (to initiailize mutex_deadlock_detector).
  Added option to turn off safe_mutex_deadlock_detector
sql/protocol.cc:
  Fixed wrong argument to DBUG_PRINT (found by valgrind)
sql/rpl_mi.cc:
  Mark mutex used inconsistently (need to be fixed by server team)
sql/set_var.cc:
  Remove wrong locking of LOCK_global_system_variables when reading and setting log variables
  (would cause inconsistent mutex order).
  Update global variables outside of logger.unlock() as LOCK_global_system_variables has to be taken before logger locks
  Reviewed by gluh
sql/sp_cache.cc:
  Added function to destroy mutex used by sp cache
sql/sp_cache.h:
  Added function to destroy mutex used by sp cache
sql/sql_class.cc:
  Use pthread_mutex_trylock instead of pthread_mutex_unlock() when sending kill signal to thread
  This is needed to avoid wrong mutex order as normally one takes 'current_mutex' before mysys_var->mutex.
  Register order in which LOCK_delete and mysys_var->mutex is taken
sql/sql_insert.cc:
  Give a name for Delayed_insert::mutex
  Mark mutex used inconsistently (need to be fixed by server team)
  Move closing of tables outside of di->mutex (to avoid wrong mutex order)
sql/sql_show.cc:
  Don't keep LOCK_global_system_variables locked over value->show_type() as this leads to wrong mutex order
storage/innobase/handler/ha_innodb.cc:
  Disable safe_muted_deadlock_detector for innobase intern mutex (to speed up page cache initialization)
storage/maria/ha_maria.cc:
  Added flag to ha_maria::info() to signal if we need to lock table share or not.
  This is needed to avoid locking mutex in wrong order
storage/maria/ha_maria.h:
  Added flag to ha_maria::info() to signal if we need to lock table share or not.
storage/maria/ma_close.c:
  Destroy key_del_lock
  Simplify freeing ftparser_param
storage/maria/ma_key.c:
  Better comment
storage/maria/ma_loghandler.c:
  Mark mutex used inconsistently (need to be fixed by sanja)
storage/maria/ma_state.c:
  More comments
storage/maria/ma_test1.c:
  Ensure that safe_mutex_deadlock_detector is always on (should be, this is just for safety)
storage/maria/ma_test2.c:
  Ensure that safe_mutex_deadlock_detector is always on (should be, this is just for safety)
2008-12-03 00:02:52 +02:00

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/* Copyright (C) 2004-2006 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include "mysql_priv.h"
#include "event_queue.h"
#include "event_data_objects.h"
/**
@addtogroup Event_Scheduler
@{
*/
#define EVENT_QUEUE_INITIAL_SIZE 30
#define EVENT_QUEUE_EXTENT 30
#ifdef __GNUC__
#if __GNUC__ >= 2
#define SCHED_FUNC __FUNCTION__
#endif
#else
#define SCHED_FUNC "<unknown>"
#endif
#define LOCK_QUEUE_DATA() lock_data(SCHED_FUNC, __LINE__)
#define UNLOCK_QUEUE_DATA() unlock_data(SCHED_FUNC, __LINE__)
/*
Compares the execute_at members of two Event_queue_element instances.
Used as callback for the prioritized queue when shifting
elements inside.
SYNOPSIS
event_queue_element_data_compare_q()
vptr Not used (set it to NULL)
a First Event_queue_element object
b Second Event_queue_element object
RETURN VALUE
-1 a->execute_at < b->execute_at
0 a->execute_at == b->execute_at
1 a->execute_at > b->execute_at
NOTES
execute_at.second_part is not considered during comparison
*/
extern "C" int event_queue_element_compare_q(void *, uchar *, uchar *);
int event_queue_element_compare_q(void *vptr, uchar* a, uchar *b)
{
Event_queue_element *left = (Event_queue_element *)a;
Event_queue_element *right = (Event_queue_element *)b;
my_time_t lhs = left->execute_at;
my_time_t rhs = right->execute_at;
if (left->status == Event_parse_data::DISABLED)
return right->status != Event_parse_data::DISABLED;
if (right->status == Event_parse_data::DISABLED)
return 1;
return (lhs < rhs ? -1 : (lhs > rhs ? 1 : 0));
}
/*
Constructor of class Event_queue.
SYNOPSIS
Event_queue::Event_queue()
*/
Event_queue::Event_queue()
:next_activation_at(0),
mutex_last_locked_at_line(0),
mutex_last_unlocked_at_line(0),
mutex_last_attempted_lock_at_line(0),
mutex_last_locked_in_func("n/a"),
mutex_last_unlocked_in_func("n/a"),
mutex_last_attempted_lock_in_func("n/a"),
mutex_queue_data_locked(FALSE),
mutex_queue_data_attempting_lock(FALSE),
waiting_on_cond(FALSE)
{
/*
Inconsisent usage between LOCK_event_queue and LOCK_scheduler_state and
LOCK_open
*/
my_pthread_mutex_init(&LOCK_event_queue, MY_MUTEX_INIT_FAST,
"LOCK_event_queue", MYF_NO_DEADLOCK_DETECTION);
pthread_cond_init(&COND_queue_state, NULL);
}
Event_queue::~Event_queue()
{
deinit_queue();
pthread_mutex_destroy(&LOCK_event_queue);
pthread_cond_destroy(&COND_queue_state);
}
/*
This is a queue's constructor. Until this method is called, the
queue is unusable. We don't use a C++ constructor instead in
order to be able to check the return value. The queue is
initialized once at server startup. Initialization can fail in
case of a failure reading events from the database or out of
memory.
SYNOPSIS
Event_queue::init()
RETURN VALUE
FALSE OK
TRUE Error
*/
bool
Event_queue::init_queue(THD *thd)
{
DBUG_ENTER("Event_queue::init_queue");
DBUG_PRINT("enter", ("this: 0x%lx", (long) this));
LOCK_QUEUE_DATA();
if (init_queue_ex(&queue, EVENT_QUEUE_INITIAL_SIZE , 0 /*offset*/,
0 /*max_on_top*/, event_queue_element_compare_q,
NULL, EVENT_QUEUE_EXTENT))
{
sql_print_error("Event Scheduler: Can't initialize the execution queue");
goto err;
}
UNLOCK_QUEUE_DATA();
DBUG_RETURN(FALSE);
err:
UNLOCK_QUEUE_DATA();
DBUG_RETURN(TRUE);
}
/*
Deinits the queue. Remove all elements from it and destroys them
too.
SYNOPSIS
Event_queue::deinit_queue()
*/
void
Event_queue::deinit_queue()
{
DBUG_ENTER("Event_queue::deinit_queue");
LOCK_QUEUE_DATA();
empty_queue();
delete_queue(&queue);
UNLOCK_QUEUE_DATA();
DBUG_VOID_RETURN;
}
/**
Adds an event to the queue.
Compute the next execution time for an event, and if it is still
active, add it to the queue. Otherwise delete it.
The object is left intact in case of an error. Otherwise
the queue container assumes ownership of it.
@param[in] thd thread handle
@param[in] new_element a new element to add to the queue
@param[out] created set to TRUE if no error and the element is
added to the queue, FALSE otherwise
@retval TRUE an error occured. The value of created is undefined,
the element was not deleted.
@retval FALSE success
*/
bool
Event_queue::create_event(THD *thd, Event_queue_element *new_element,
bool *created)
{
DBUG_ENTER("Event_queue::create_event");
DBUG_PRINT("enter", ("thd: 0x%lx et=%s.%s", (long) thd,
new_element->dbname.str, new_element->name.str));
/* Will do nothing if the event is disabled */
new_element->compute_next_execution_time();
if (new_element->status != Event_parse_data::ENABLED)
{
delete new_element;
*created= FALSE;
DBUG_RETURN(FALSE);
}
DBUG_PRINT("info", ("new event in the queue: 0x%lx", (long) new_element));
LOCK_QUEUE_DATA();
*created= (queue_insert_safe(&queue, (uchar *) new_element) == FALSE);
dbug_dump_queue(thd->query_start());
pthread_cond_broadcast(&COND_queue_state);
UNLOCK_QUEUE_DATA();
DBUG_RETURN(!*created);
}
/*
Updates an event from the scheduler queue
SYNOPSIS
Event_queue::update_event()
thd Thread
dbname Schema of the event
name Name of the event
new_schema New schema, in case of RENAME TO, otherwise NULL
new_name New name, in case of RENAME TO, otherwise NULL
*/
void
Event_queue::update_event(THD *thd, LEX_STRING dbname, LEX_STRING name,
Event_queue_element *new_element)
{
DBUG_ENTER("Event_queue::update_event");
DBUG_PRINT("enter", ("thd: 0x%lx et=[%s.%s]", (long) thd, dbname.str, name.str));
if ((new_element->status == Event_parse_data::DISABLED) ||
(new_element->status == Event_parse_data::SLAVESIDE_DISABLED))
{
DBUG_PRINT("info", ("The event is disabled."));
/*
Destroy the object but don't skip to end: because we may have to remove
object from the cache.
*/
delete new_element;
new_element= NULL;
}
else
new_element->compute_next_execution_time();
LOCK_QUEUE_DATA();
find_n_remove_event(dbname, name);
/* If not disabled event */
if (new_element)
{
DBUG_PRINT("info", ("new event in the queue: 0x%lx", (long) new_element));
queue_insert_safe(&queue, (uchar *) new_element);
pthread_cond_broadcast(&COND_queue_state);
}
dbug_dump_queue(thd->query_start());
UNLOCK_QUEUE_DATA();
DBUG_VOID_RETURN;
}
/*
Drops an event from the queue
SYNOPSIS
Event_queue::drop_event()
thd Thread
dbname Schema of the event to drop
name Name of the event to drop
*/
void
Event_queue::drop_event(THD *thd, LEX_STRING dbname, LEX_STRING name)
{
DBUG_ENTER("Event_queue::drop_event");
DBUG_PRINT("enter", ("thd: 0x%lx db :%s name: %s", (long) thd,
dbname.str, name.str));
LOCK_QUEUE_DATA();
find_n_remove_event(dbname, name);
dbug_dump_queue(thd->query_start());
UNLOCK_QUEUE_DATA();
/*
We don't signal here because the scheduler will catch the change
next time it wakes up.
*/
DBUG_VOID_RETURN;
}
/*
Drops all events from the in-memory queue and disk that match
certain pattern evaluated by a comparator function
SYNOPSIS
Event_queue::drop_matching_events()
thd THD
pattern A pattern string
comparator The function to use for comparing
RETURN VALUE
>=0 Number of dropped events
NOTE
Expected is the caller to acquire lock on LOCK_event_queue
*/
void
Event_queue::drop_matching_events(THD *thd, LEX_STRING pattern,
bool (*comparator)(LEX_STRING, Event_basic *))
{
uint i= 0;
DBUG_ENTER("Event_queue::drop_matching_events");
DBUG_PRINT("enter", ("pattern=%s", pattern.str));
while (i < queue.elements)
{
Event_queue_element *et= (Event_queue_element *) queue_element(&queue, i);
DBUG_PRINT("info", ("[%s.%s]?", et->dbname.str, et->name.str));
if (comparator(pattern, et))
{
/*
The queue is ordered. If we remove an element, then all elements
after it will shift one position to the left, if we imagine it as
an array from left to the right. In this case we should not
increment the counter and the (i < queue.elements) condition is ok.
*/
queue_remove(&queue, i);
delete et;
}
else
i++;
}
/*
We don't call pthread_cond_broadcast(&COND_queue_state);
If we remove the top event:
1. The queue is empty. The scheduler will wake up at some time and
realize that the queue is empty. If create_event() comes inbetween
it will signal the scheduler
2. The queue is not empty, but the next event after the previous top,
won't be executed any time sooner than the element we removed. Hence,
we may not notify the scheduler and it will realize the change when it
wakes up from timedwait.
*/
DBUG_VOID_RETURN;
}
/*
Drops all events from the in-memory queue and disk that are from
certain schema.
SYNOPSIS
Event_queue::drop_schema_events()
thd HD
schema The schema name
*/
void
Event_queue::drop_schema_events(THD *thd, LEX_STRING schema)
{
DBUG_ENTER("Event_queue::drop_schema_events");
LOCK_QUEUE_DATA();
drop_matching_events(thd, schema, event_basic_db_equal);
UNLOCK_QUEUE_DATA();
DBUG_VOID_RETURN;
}
/*
Searches for an event in the queue
SYNOPSIS
Event_queue::find_n_remove_event()
db The schema of the event to find
name The event to find
NOTE
The caller should do the locking also the caller is responsible for
actual signalling in case an event is removed from the queue.
*/
void
Event_queue::find_n_remove_event(LEX_STRING db, LEX_STRING name)
{
uint i;
DBUG_ENTER("Event_queue::find_n_remove_event");
for (i= 0; i < queue.elements; ++i)
{
Event_queue_element *et= (Event_queue_element *) queue_element(&queue, i);
DBUG_PRINT("info", ("[%s.%s]==[%s.%s]?", db.str, name.str,
et->dbname.str, et->name.str));
if (event_basic_identifier_equal(db, name, et))
{
queue_remove(&queue, i);
delete et;
break;
}
}
DBUG_VOID_RETURN;
}
/*
Recalculates activation times in the queue. There is one reason for
that. Because the values (execute_at) by which the queue is ordered are
changed by calls to compute_next_execution_time() on a request from the
scheduler thread, if it is not running then the values won't be updated.
Once the scheduler is started again the values has to be recalculated
so they are right for the current time.
SYNOPSIS
Event_queue::recalculate_activation_times()
thd Thread
*/
void
Event_queue::recalculate_activation_times(THD *thd)
{
uint i;
DBUG_ENTER("Event_queue::recalculate_activation_times");
LOCK_QUEUE_DATA();
DBUG_PRINT("info", ("%u loaded events to be recalculated", queue.elements));
for (i= 0; i < queue.elements; i++)
{
((Event_queue_element*)queue_element(&queue, i))->compute_next_execution_time();
((Event_queue_element*)queue_element(&queue, i))->update_timing_fields(thd);
}
queue_fix(&queue);
/*
The disabled elements are moved to the end during the `fix`.
Start from the end and remove all of the elements which are
disabled. When we find the first non-disabled one we break, as we
have removed all. The queue has been ordered in a way the disabled
events are at the end.
*/
for (i= queue.elements; i > 0; i--)
{
Event_queue_element *element = (Event_queue_element*)queue_element(&queue, i - 1);
if (element->status != Event_parse_data::DISABLED)
break;
/*
This won't cause queue re-order, because we remove
always the last element.
*/
queue_remove(&queue, i - 1);
delete element;
}
UNLOCK_QUEUE_DATA();
/*
XXX: The events are dropped only from memory and not from disk
even if `drop_list[j]->dropped` is TRUE. There will be still on the
disk till next server restart.
Please add code here to do it.
*/
DBUG_VOID_RETURN;
}
/*
Empties the queue and destroys the Event_queue_element objects in the
queue.
SYNOPSIS
Event_queue::empty_queue()
NOTE
Should be called with LOCK_event_queue locked
*/
void
Event_queue::empty_queue()
{
uint i;
DBUG_ENTER("Event_queue::empty_queue");
DBUG_PRINT("enter", ("Purging the queue. %u element(s)", queue.elements));
sql_print_information("Event Scheduler: Purging the queue. %u events",
queue.elements);
/* empty the queue */
for (i= 0; i < queue.elements; ++i)
{
Event_queue_element *et= (Event_queue_element *) queue_element(&queue, i);
delete et;
}
resize_queue(&queue, 0);
DBUG_VOID_RETURN;
}
/*
Dumps the queue to the trace log.
SYNOPSIS
Event_queue::dbug_dump_queue()
now Current timestamp
*/
void
Event_queue::dbug_dump_queue(time_t now)
{
#ifndef DBUG_OFF
Event_queue_element *et;
uint i;
DBUG_ENTER("Event_queue::dbug_dump_queue");
DBUG_PRINT("info", ("Dumping queue . Elements=%u", queue.elements));
for (i = 0; i < queue.elements; i++)
{
et= ((Event_queue_element*)queue_element(&queue, i));
DBUG_PRINT("info", ("et: 0x%lx name: %s.%s", (long) et,
et->dbname.str, et->name.str));
DBUG_PRINT("info", ("exec_at: %lu starts: %lu ends: %lu execs_so_far: %u "
"expr: %ld et.exec_at: %ld now: %ld "
"(et.exec_at - now): %d if: %d",
(long) et->execute_at, (long) et->starts,
(long) et->ends, et->execution_count,
(long) et->expression, (long) et->execute_at,
(long) now, (int) (et->execute_at - now),
et->execute_at <= now));
}
DBUG_VOID_RETURN;
#endif
}
static const char *queue_empty_msg= "Waiting on empty queue";
static const char *queue_wait_msg= "Waiting for next activation";
/*
Checks whether the top of the queue is elligible for execution and
returns an Event_job_data instance in case it should be executed.
`now` is compared against `execute_at` of the top element in the queue.
SYNOPSIS
Event_queue::get_top_for_execution_if_time()
thd [in] Thread
event_name [out] The object to execute
RETURN VALUE
FALSE No error. event_name != NULL
TRUE Serious error
*/
bool
Event_queue::get_top_for_execution_if_time(THD *thd,
Event_queue_element_for_exec **event_name)
{
bool ret= FALSE;
*event_name= NULL;
DBUG_ENTER("Event_queue::get_top_for_execution_if_time");
LOCK_QUEUE_DATA();
for (;;)
{
Event_queue_element *top= NULL;
/* Break loop if thd has been killed */
if (thd->killed)
{
DBUG_PRINT("info", ("thd->killed=%d", thd->killed));
goto end;
}
if (!queue.elements)
{
/* There are no events in the queue */
next_activation_at= 0;
/* Wait on condition until signaled. Release LOCK_queue while waiting. */
cond_wait(thd, NULL, queue_empty_msg, SCHED_FUNC, __LINE__);
continue;
}
top= ((Event_queue_element*) queue_element(&queue, 0));
thd->set_current_time(); /* Get current time */
next_activation_at= top->execute_at;
if (next_activation_at > thd->query_start())
{
/*
Not yet time for top event, wait on condition with
time or until signaled. Release LOCK_queue while waiting.
*/
struct timespec top_time;
set_timespec(top_time, next_activation_at - thd->query_start());
cond_wait(thd, &top_time, queue_wait_msg, SCHED_FUNC, __LINE__);
continue;
}
if (!(*event_name= new Event_queue_element_for_exec()) ||
(*event_name)->init(top->dbname, top->name))
{
ret= TRUE;
break;
}
DBUG_PRINT("info", ("Ready for execution"));
top->mark_last_executed(thd);
if (top->compute_next_execution_time())
top->status= Event_parse_data::DISABLED;
DBUG_PRINT("info", ("event %s status is %d", top->name.str, top->status));
top->execution_count++;
(*event_name)->dropped= top->dropped;
top->update_timing_fields(thd);
if (top->status == Event_parse_data::DISABLED)
{
DBUG_PRINT("info", ("removing from the queue"));
sql_print_information("Event Scheduler: Last execution of %s.%s. %s",
top->dbname.str, top->name.str,
top->dropped? "Dropping.":"");
delete top;
queue_remove(&queue, 0);
}
else
queue_replaced(&queue);
dbug_dump_queue(thd->query_start());
break;
}
end:
UNLOCK_QUEUE_DATA();
DBUG_PRINT("info", ("returning %d et_new: 0x%lx ",
ret, (long) *event_name));
if (*event_name)
DBUG_PRINT("info", ("db: %s name: %s",
(*event_name)->dbname.str, (*event_name)->name.str));
DBUG_RETURN(ret);
}
/*
Auxiliary function for locking LOCK_event_queue. Used by the
LOCK_QUEUE_DATA macro
SYNOPSIS
Event_queue::lock_data()
func Which function is requesting mutex lock
line On which line mutex lock is requested
*/
void
Event_queue::lock_data(const char *func, uint line)
{
DBUG_ENTER("Event_queue::lock_data");
DBUG_PRINT("enter", ("func=%s line=%u", func, line));
mutex_last_attempted_lock_in_func= func;
mutex_last_attempted_lock_at_line= line;
mutex_queue_data_attempting_lock= TRUE;
pthread_mutex_lock(&LOCK_event_queue);
mutex_last_attempted_lock_in_func= "";
mutex_last_attempted_lock_at_line= 0;
mutex_queue_data_attempting_lock= FALSE;
mutex_last_locked_in_func= func;
mutex_last_locked_at_line= line;
mutex_queue_data_locked= TRUE;
DBUG_VOID_RETURN;
}
/*
Auxiliary function for unlocking LOCK_event_queue. Used by the
UNLOCK_QUEUE_DATA macro
SYNOPSIS
Event_queue::unlock_data()
func Which function is requesting mutex unlock
line On which line mutex unlock is requested
*/
void
Event_queue::unlock_data(const char *func, uint line)
{
DBUG_ENTER("Event_queue::unlock_data");
DBUG_PRINT("enter", ("func=%s line=%u", func, line));
mutex_last_unlocked_at_line= line;
mutex_queue_data_locked= FALSE;
mutex_last_unlocked_in_func= func;
pthread_mutex_unlock(&LOCK_event_queue);
DBUG_VOID_RETURN;
}
/*
Wrapper for pthread_cond_wait/timedwait
SYNOPSIS
Event_queue::cond_wait()
thd Thread (Could be NULL during shutdown procedure)
msg Message for thd->proc_info
abstime If not null then call pthread_cond_timedwait()
func Which function is requesting cond_wait
line On which line cond_wait is requested
*/
void
Event_queue::cond_wait(THD *thd, struct timespec *abstime, const char* msg,
const char *func, uint line)
{
DBUG_ENTER("Event_queue::cond_wait");
waiting_on_cond= TRUE;
mutex_last_unlocked_at_line= line;
mutex_queue_data_locked= FALSE;
mutex_last_unlocked_in_func= func;
thd->enter_cond(&COND_queue_state, &LOCK_event_queue, msg);
DBUG_PRINT("info", ("pthread_cond_%swait", abstime? "timed":""));
if (!abstime)
pthread_cond_wait(&COND_queue_state, &LOCK_event_queue);
else
pthread_cond_timedwait(&COND_queue_state, &LOCK_event_queue, abstime);
mutex_last_locked_in_func= func;
mutex_last_locked_at_line= line;
mutex_queue_data_locked= TRUE;
waiting_on_cond= FALSE;
/*
This will free the lock so we need to relock. Not the best thing to
do but we need to obey cond_wait()
*/
thd->exit_cond("");
lock_data(func, line);
DBUG_VOID_RETURN;
}
/*
Dumps the internal status of the queue
SYNOPSIS
Event_queue::dump_internal_status()
*/
void
Event_queue::dump_internal_status()
{
DBUG_ENTER("Event_queue::dump_internal_status");
/* element count */
puts("");
puts("Event queue status:");
printf("Element count : %u\n", queue.elements);
printf("Data locked : %s\n", mutex_queue_data_locked? "YES":"NO");
printf("Attempting lock : %s\n", mutex_queue_data_attempting_lock? "YES":"NO");
printf("LLA : %s:%u\n", mutex_last_locked_in_func,
mutex_last_locked_at_line);
printf("LUA : %s:%u\n", mutex_last_unlocked_in_func,
mutex_last_unlocked_at_line);
if (mutex_last_attempted_lock_at_line)
printf("Last lock attempt at: %s:%u\n", mutex_last_attempted_lock_in_func,
mutex_last_attempted_lock_at_line);
printf("WOC : %s\n", waiting_on_cond? "YES":"NO");
MYSQL_TIME time;
my_tz_OFFSET0->gmt_sec_to_TIME(&time, next_activation_at);
if (time.year != 1970)
printf("Next activation : %04d-%02d-%02d %02d:%02d:%02d\n",
time.year, time.month, time.day, time.hour, time.minute, time.second);
else
printf("Next activation : never");
DBUG_VOID_RETURN;
}
/**
@} (End of group Event_Scheduler)
*/
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