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Fix for bug #12739 "Deadlock in multithreaded environment during creating/

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droping trigger on InnoDB table".

Deadlock occured in cases when we were trying to create two triggers for
the same InnoDB table concurrently and both threads were able to reach
close_cached_table() simultaneously. Bugfix implements new approach to
table locking and table cache invalidation during creation/dropping
of trigger.

No testcase is supplied since bug was repeatable only under high concurrency.
This commit is contained in:
dlenev@mysql.com
2005-10-17 22:37:24 +04:00
parent dad1e2048d
commit ea0b89aeae
4 changed files with 99 additions and 66 deletions
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64
sql/sql_base.cc
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@@ -976,32 +976,57 @@ void wait_for_refresh(THD *thd)
}
TABLE *reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
{
DBUG_ENTER("reopen_name_locked_table");
if (thd->killed)
DBUG_RETURN(0);
TABLE *table;
TABLE_SHARE *share;
if (!(table = table_list->table))
DBUG_RETURN(0);
/*
Open table which is already name-locked by this thread.
char* db = thd->db ? thd->db : table_list->db;
char* table_name = table_list->table_name;
char key[MAX_DBKEY_LENGTH];
uint key_length;
SYNOPSIS
reopen_name_locked_table()
thd Thread handle
table_list TABLE_LIST object for table to be open, TABLE_LIST::table
member should point to TABLE object which was used for
name-locking.
NOTE
This function assumes that its caller already acquired LOCK_open mutex.
RETURN VALUE
FALSE - Success
TRUE - Error
*/
bool reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
{
TABLE *table= table_list->table;
TABLE_SHARE *share;
char *db= table_list->db;
char *table_name= table_list->table_name;
char key[MAX_DBKEY_LENGTH];
uint key_length;
TABLE orig_table;
DBUG_ENTER("reopen_name_locked_table");
safe_mutex_assert_owner(&LOCK_open);
if (thd->killed || !table)
DBUG_RETURN(TRUE);
orig_table= *table;
key_length=(uint) (strmov(strmov(key,db)+1,table_name)-key)+1;
pthread_mutex_lock(&LOCK_open);
if (open_unireg_entry(thd, table, db, table_name, table_name, 0,
thd->mem_root) ||
!(table->s->table_cache_key= memdup_root(&table->mem_root, (char*) key,
key_length)))
{
delete table->triggers;
closefrm(table);
pthread_mutex_unlock(&LOCK_open);
DBUG_RETURN(0);
intern_close_table(table);
/*
If there was an error during opening of table (for example if it
does not exist) '*table' object can be wiped out. To be able
properly release name-lock in this case we should restore this
object to its original state.
*/
*table= orig_table;
DBUG_RETURN(TRUE);
}
share= table->s;
@@ -1011,7 +1036,6 @@ TABLE *reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
share->flush_version=0;
table->in_use = thd;
check_unused();
pthread_mutex_unlock(&LOCK_open);
table->next = thd->open_tables;
thd->open_tables = table;
table->tablenr=thd->current_tablenr++;
@@ -1021,7 +1045,7 @@ TABLE *reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
table->status=STATUS_NO_RECORD;
table->keys_in_use_for_query= share->keys_in_use;
table->used_keys= share->keys_for_keyread;
DBUG_RETURN(table);
DBUG_RETURN(FALSE);
}