Reuse THD for new user connections

- To ensure that mallocs are marked for the correct THD, even if it's
  allocated in another thread, I added the thread_id to the THD constructor
- Added st_my_thread_var to thr_lock_info_init() to avoid a call to my_thread_var
- Moved things from THD::THD() to THD::init()
- Moved some things to THD::cleanup()
- Added THD::free_connection() and THD::reset_for_reuse()
- Added THD to CONNECT::create_thd()
- Added THD::thread_dbug_id and st_my_thread_var->dbug_id. These are needed
  to ensure that we have a constant thread_id used for debugging with a THD,
  even if it changes thread_id (=connection_id)
- Set variables.pseudo_thread_id in constructor. Removed not needed sets.

1 files changed, 1 insertions, 1 deletions

diff --git a/include/my_pthread.h b/include/my_pthread.h
index de1f0af070a..3459180b9b2 100644
--- a/include/my_pthread.h
+++ b/include/my_pthread.h
@@ -691,7 +691,7 @@ struct st_my_thread_var
   mysql_mutex_t * volatile current_mutex;
   mysql_cond_t * volatile current_cond;
   pthread_t pthread_self;
-  my_thread_id id;
+  my_thread_id id, dbug_id;
   int volatile abort;
   my_bool init;
   struct st_my_thread_var *next,**prev;