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Bug #10600

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remove_table_from_cache fails to signal other thread and gets
blocked when other thread also gets blocked


include/thr_lock.h:
  Report if any threads was signalled
mysys/thr_lock.c:
  Report if any threads was signalled
sql/lock.cc:
  Report if any threads was signalled
  Use new interface for remove_table_from_cache
sql/mysql_priv.h:
  New interface for remove_table_from_cache
  + mysql_lock_abort_for_thread
sql/sql_base.cc:
  Use new interface of remove_table_cache
  Rewrote remove_table_from_cache to fix bug
sql/sql_table.cc:
  Use new interface of remove_table_from_cache
This commit is contained in:
unknown
2005-07-19 00:29:19 +02:00
parent 5c27ff06c7
commit 6d29b23b15
6 changed files with 133 additions and 77 deletions
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132
sql/sql_base.cc
View File

@ -370,7 +370,9 @@ bool close_cached_tables(THD *thd, bool if_wait_for_refresh,
bool found=0;
for (TABLE_LIST *table=tables ; table ; table=table->next)
{
if (remove_table_from_cache(thd, table->db, table->real_name, 1))
uint flags= OWNED_BY_THD_FLAG;
if (remove_table_from_cache(thd, table->db, table->real_name,
flags))
found=1;
}
if (!found)
@ -2407,62 +2409,106 @@ void flush_tables()
*/
bool remove_table_from_cache(THD *thd, const char *db, const char *table_name,
bool return_if_owned_by_thd)
uint flags)
{
char key[MAX_DBKEY_LENGTH];
uint key_length;
TABLE *table;
bool result=0;
bool result=0, signalled= 0;
bool return_if_owned_by_thd= flags & OWNED_BY_THD_FLAG;
bool wait_for_other_thread= flags & WAIT_OTHER_THREAD_FLAG;
bool check_killed_flag= flags & CHECK_KILLED_FLAG;
DBUG_ENTER("remove_table_from_cache");
key_length=(uint) (strmov(strmov(key,db)+1,table_name)-key)+1;
for (table=(TABLE*) hash_search(&open_cache,(byte*) key,key_length) ;
table;
table = (TABLE*) hash_next(&open_cache,(byte*) key,key_length))
do
{
THD *in_use;
table->version=0L; /* Free when thread is ready */
if (!(in_use=table->in_use))
result= signalled= 0;
for (table=(TABLE*) hash_search(&open_cache,(byte*) key,key_length) ;
table;
table = (TABLE*) hash_next(&open_cache,(byte*) key,key_length))
{
DBUG_PRINT("info",("Table was not in use"));
relink_unused(table);
}
else if (in_use != thd)
{
in_use->some_tables_deleted=1;
if (table->db_stat)
result=1;
/* Kill delayed insert threads */
if ((in_use->system_thread & SYSTEM_THREAD_DELAYED_INSERT) &&
! in_use->killed)
THD *in_use;
table->version=0L; /* Free when thread is ready */
if (!(in_use=table->in_use))
{
in_use->killed=1;
pthread_mutex_lock(&in_use->mysys_var->mutex);
if (in_use->mysys_var->current_cond)
{
pthread_mutex_lock(in_use->mysys_var->current_mutex);
pthread_cond_broadcast(in_use->mysys_var->current_cond);
pthread_mutex_unlock(in_use->mysys_var->current_mutex);
}
pthread_mutex_unlock(&in_use->mysys_var->mutex);
DBUG_PRINT("info",("Table was not in use"));
relink_unused(table);
}
/*
Now we must abort all tables locks used by this thread
as the thread may be waiting to get a lock for another table
*/
for (TABLE *thd_table= in_use->open_tables;
thd_table ;
thd_table= thd_table->next)
else if (in_use != thd)
{
if (thd_table->db_stat) // If table is open
mysql_lock_abort_for_thread(thd, thd_table);
in_use->some_tables_deleted=1;
if (table->db_stat)
result=1;
/* Kill delayed insert threads */
if ((in_use->system_thread & SYSTEM_THREAD_DELAYED_INSERT) &&
! in_use->killed)
{
in_use->killed=1;
pthread_mutex_lock(&in_use->mysys_var->mutex);
if (in_use->mysys_var->current_cond)
{
pthread_mutex_lock(in_use->mysys_var->current_mutex);
signalled= 1;
pthread_cond_broadcast(in_use->mysys_var->current_cond);
pthread_mutex_unlock(in_use->mysys_var->current_mutex);
}
pthread_mutex_unlock(&in_use->mysys_var->mutex);
}
/*
Now we must abort all tables locks used by this thread
as the thread may be waiting to get a lock for another table
*/
for (TABLE *thd_table= in_use->open_tables;
thd_table ;
thd_table= thd_table->next)
{
if (thd_table->db_stat) // If table is open
{
bool found;
found= mysql_lock_abort_for_thread(thd, thd_table);
signalled|= found;
}
}
}
else
result= result || return_if_owned_by_thd;
}
while (unused_tables && !unused_tables->version)
VOID(hash_delete(&open_cache,(byte*) unused_tables));
if (result && wait_for_other_thread)
{
if (!check_killed_flag || !thd->killed)
{
if (likely(signalled))
{
dropping_tables++;
(void) pthread_cond_wait(&COND_refresh, &LOCK_open);
dropping_tables--;
continue;
}
else
{
/*
It can happen that another thread has opened the
table but has not yet locked any table at all. Since
it can be locked waiting for a table that our thread
has done LOCK TABLE x WRITE on previously, we need to
ensure that the thread actually hears our signal
before we go to sleep. Thus we wait for a short time
and then we retry another loop in the
remove_table_from_cache routine.
*/
pthread_mutex_unlock(&LOCK_open);
my_sleep(10);
pthread_mutex_lock(&LOCK_open);
continue;
}
}
}
else
result= result || return_if_owned_by_thd;
}
while (unused_tables && !unused_tables->version)
VOID(hash_delete(&open_cache,(byte*) unused_tables));
break;
} while (1);
DBUG_RETURN(result);
}