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Code Activity

Move thread re-initialisation out of cache_thread

Browse Source 
It mostly duplicates code of do_handle_one_connection(). Move it there,
so that it is easier to simplify it in future.

Moved PSI_CALL_delete_current_thread()/_db_pop_() out of mutex. Call them
consistently in all cases, unlike before:
- called for reused threads
- called for flushed threads
- called for threads that go down after 5 minutes timeout
- not called for threads attempting to cache themselves during flush
- not called for threads attempting to cache themselves when cache is full

Part of MDEV-19515 - Improve connect speed
This commit is contained in:
Sergey Vojtovich
2019-05-18 23:01:44 +04:00
parent ebc55c8577
commit 34dfcbe3a6
3 changed files with 43 additions and 44 deletions
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55
sql/mysqld.cc
View File

@ -2663,31 +2663,30 @@ void unlink_thd(THD *thd)
*/
bool cache_thread(THD *thd)
CONNECT *cache_thread(THD *thd)
{
struct timespec abstime;
DBUG_ENTER("cache_thread");
DBUG_ASSERT(thd);
set_timespec(abstime, THREAD_CACHE_TIMEOUT);
/*
Delete the instrumentation for the job that just completed,
before parking this pthread in the cache (blocked on COND_thread_cache).
*/
PSI_CALL_delete_current_thread();
#ifndef DBUG_OFF
while (_db_is_pushed_())
_db_pop_();
#endif
mysql_mutex_lock(&LOCK_thread_cache);
if (cached_thread_count < thread_cache_size && !kill_cached_threads)
{
/* Don't kill the thread, just put it in cache for reuse */
DBUG_PRINT("info", ("Adding thread to cache"));
cached_thread_count++;
/*
Delete the instrumentation for the job that just completed,
before parking this pthread in the cache (blocked on COND_thread_cache).
*/
PSI_CALL_delete_current_thread();
#ifndef DBUG_OFF
while (_db_is_pushed_())
_db_pop_();
#endif
while (!wake_thread)
{
int error= mysql_cond_timedwait(&COND_thread_cache, &LOCK_thread_cache,
@ -2712,35 +2711,7 @@ bool cache_thread(THD *thd)
{
wake_thread--;
mysql_mutex_unlock(&LOCK_thread_cache);
if (!(connect->create_thd(thd)))
{
/* Out of resources. Free thread to get more resources */
connect->close_and_delete();
DBUG_RETURN(0);
}
delete connect;
/*
We have to call store_globals to update mysys_var->id and lock_info
with the new thread_id
*/
thd->store_globals();
/*
Create new instrumentation for the new THD job,
and attach it to this running pthread.
*/
PSI_CALL_set_thread(PSI_CALL_new_thread(key_thread_one_connection,
thd, thd->thread_id));
/* reset abort flag for the thread */
thd->mysys_var->abort= 0;
thd->thr_create_utime= microsecond_interval_timer();
thd->start_utime= thd->thr_create_utime;
server_threads.insert(thd);
DBUG_RETURN(1);
DBUG_RETURN(connect);
}
}
mysql_mutex_unlock(&LOCK_thread_cache);

2
sql/mysqld.h
View File

@ -79,7 +79,7 @@ void close_connection(THD *thd, uint sql_errno= 0);
void handle_connection_in_main_thread(CONNECT *thd);
void create_thread_to_handle_connection(CONNECT *connect);
void unlink_thd(THD *thd);
bool cache_thread(THD *thd);
CONNECT *cache_thread(THD *thd);
void flush_thread_cache();
void refresh_status(THD *thd);
bool is_secure_file_path(char *path);

30
sql/sql_connect.cc
View File

@ -1426,8 +1426,36 @@ end_thread:
unlink_thd(thd);
if (IF_WSREP(thd->wsrep_applier, false) || !put_in_cache ||
!cache_thread(thd))
!(connect= cache_thread(thd)))
break;
if (!(connect->create_thd(thd)))
{
/* Out of resources. Free thread to get more resources */
connect->close_and_delete();
break;
}
delete connect;
/*
We have to call store_globals to update mysys_var->id and lock_info
with the new thread_id
*/
thd->store_globals();
/*
Create new instrumentation for the new THD job,
and attach it to this running pthread.
*/
PSI_CALL_set_thread(PSI_CALL_new_thread(key_thread_one_connection,
thd, thd->thread_id));
/* reset abort flag for the thread */
thd->mysys_var->abort= 0;
thd->thr_create_utime= microsecond_interval_timer();
thd->start_utime= thd->thr_create_utime;
server_threads.insert(thd);
}
delete thd;
}