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Simplified THD::current_linfo locking

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LOG_INFO::lock was useless. It could've only protect against concurrent
iterators execution, which was already protected by LOCK_thread_count.

Use LOCK_thd_data instead of LOCK_thread_count as a protection against
THD::current_linfo reset.

Aim is to reduce usage of LOCK_thread_count and COND_thread_count.
Part of MDEV-15135.
This commit is contained in:
Sergey Vojtovich 2019-01-20 12:51:20 +04:00
parent c88fd54d17
commit 891be49a36
5 changed files with 10 additions and 26 deletions
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1
mysql-test/suite/perfschema/r/setup_instruments_defaults.result
View File

@ -25,7 +25,6 @@ WHERE name IN (
AND enabled = 'yes' AND timed = 'yes'
ORDER BY name;
NAME ENABLED TIMED
wait/synch/mutex/sql/LOG_INFO::lock YES YES
wait/synch/mutex/sql/THD::LOCK_thd_data YES YES
SELECT * FROM performance_schema.setup_instruments
WHERE name = 'wait/synch/mutex/sql/hash_filo::lock'

12
sql/log.h
View File

@ -247,10 +247,6 @@ extern TC_LOG_DUMMY tc_log_dummy;
class Relay_log_info;
#ifdef HAVE_PSI_INTERFACE
extern PSI_mutex_key key_LOG_INFO_lock;
#endif
/*
Note that we destroy the lock mutex in the desctructor here.
This means that object instances cannot be destroyed/go out of scope,
@ -262,19 +258,11 @@ typedef struct st_log_info
my_off_t index_file_offset, index_file_start_offset;
my_off_t pos;
bool fatal; // if the purge happens to give us a negative offset
mysql_mutex_t lock;
st_log_info() : index_file_offset(0), index_file_start_offset(0),
pos(0), fatal(0)
{
DBUG_ENTER("LOG_INFO");
log_file_name[0] = '\0';
mysql_mutex_init(key_LOG_INFO_lock, &lock, MY_MUTEX_INIT_FAST);
DBUG_VOID_RETURN;
}
~st_log_info()
{
DBUG_ENTER("~LOG_INFO");
mysql_mutex_destroy(&lock);
DBUG_VOID_RETURN;
}
} LOG_INFO;

3
sql/mysqld.cc
View File

@ -908,7 +908,7 @@ PSI_mutex_key key_BINLOG_LOCK_index, key_BINLOG_LOCK_xid_list,
key_rpl_group_info_sleep_lock,
key_relay_log_info_log_space_lock, key_relay_log_info_run_lock,
key_structure_guard_mutex, key_TABLE_SHARE_LOCK_ha_data,
key_LOCK_error_messages, key_LOG_INFO_lock,
key_LOCK_error_messages,
key_LOCK_start_thread,
key_LOCK_thread_count, key_LOCK_thread_cache,
key_PARTITION_LOCK_auto_inc;
@ -1003,7 +1003,6 @@ static PSI_mutex_info all_server_mutexes[]=
{ &key_LOCK_after_binlog_sync, "LOCK_after_binlog_sync", PSI_FLAG_GLOBAL},
{ &key_LOCK_commit_ordered, "LOCK_commit_ordered", PSI_FLAG_GLOBAL},
{ &key_LOCK_slave_background, "LOCK_slave_background", PSI_FLAG_GLOBAL},
{ &key_LOG_INFO_lock, "LOG_INFO::lock", 0},
{ &key_LOCK_thread_count, "LOCK_thread_count", PSI_FLAG_GLOBAL},
{ &key_LOCK_thread_cache, "LOCK_thread_cache", PSI_FLAG_GLOBAL},
{ &key_PARTITION_LOCK_auto_inc, "HA_DATA_PARTITION::LOCK_auto_inc", 0},

6
sql/sql_class.h
View File

@ -4934,15 +4934,15 @@ public:
}
/*
Reset current_linfo
Setting current_linfo to 0 needs to be done with LOCK_thread_count to
Setting current_linfo to 0 needs to be done with LOCK_thd_data to
ensure that adjust_linfo_offsets doesn't use a structure that may
be deleted.
*/
inline void reset_current_linfo()
{
mysql_mutex_lock(&LOCK_thread_count);
mysql_mutex_lock(&LOCK_thd_data);
current_linfo= 0;
mysql_mutex_unlock(&LOCK_thread_count);
mysql_mutex_unlock(&LOCK_thd_data);
}

14
sql/sql_repl.cc
View File

@ -537,9 +537,9 @@ void adjust_linfo_offsets(my_off_t purge_offset)
while ((tmp=it++))
{
LOG_INFO* linfo;
mysql_mutex_lock(&tmp->LOCK_thd_data);
if ((linfo = tmp->current_linfo))
{
mysql_mutex_lock(&linfo->lock);
/*
Index file offset can be less that purge offset only if
we just started reading the index file. In that case
@ -549,8 +549,8 @@ void adjust_linfo_offsets(my_off_t purge_offset)
linfo->fatal = (linfo->index_file_offset != 0);
else
linfo->index_file_offset -= purge_offset;
mysql_mutex_unlock(&linfo->lock);
}
mysql_mutex_unlock(&tmp->LOCK_thd_data);
}
mysql_mutex_unlock(&LOCK_thread_count);
}
@ -568,14 +568,12 @@ bool log_in_use(const char* log_name)
while ((tmp=it++))
{
LOG_INFO* linfo;
mysql_mutex_lock(&tmp->LOCK_thd_data);
if ((linfo = tmp->current_linfo))
{
mysql_mutex_lock(&linfo->lock);
result = !memcmp(log_name, linfo->log_file_name, log_name_len);
mysql_mutex_unlock(&linfo->lock);
if (result)
break;
}
mysql_mutex_unlock(&tmp->LOCK_thd_data);
if (result)
break;
}
mysql_mutex_unlock(&LOCK_thread_count);