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/sql/tztime.cc b/sql/tztime.cc
index ce0272d996d..a9db91668bb 100644
--- a/sql/tztime.cc
+++ b/sql/tztime.cc
@@ -1620,7 +1620,7 @@ my_tz_init(THD *org_thd, const char *default_tzname, my_bool bootstrap)
   /*
     To be able to run this from boot, we allocate a temporary THD
   */
-  if (!(thd= new THD))
+  if (!(thd= new THD(0)))
     DBUG_RETURN(1);
   thd->thread_stack= (char*) &thd;
   thd->store_globals();