Simpler arena swapping code

Now thd->mem_root is a pointer to thd->main_mem_root and THR_MALLOC is a pointer to thd->mem_root.
This gives us the following benefits:
- Allow us to easily detect if arena has already been swapped before (this fixes a bug in setup_conds() where arena was swaped twice in some cases)
- Faster swaps of arenas (as we don't have to copy the whole MEM_ROOT)
- We don't anymore have to call my_pthread_setspecific_ptr(THR_MALLOC,...) to change where memory is alloced. Now it's enough to set thd->mem_root

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/sql_db.cc b/sql/sql_db.cc
index eb851e79d2e..e50796f2a33 100644
--- a/sql/sql_db.cc
+++ b/sql/sql_db.cc
@@ -725,7 +725,7 @@ static long mysql_rm_known_files(THD *thd, MY_DIR *dirp, const char *db,
 	if ((mysql_rm_known_files(thd, new_dirp, NullS, newpath,1)) < 0)
 	  goto err;
 	if (!(copy_of_path= thd->memdup(newpath, length+1)) ||
-	    !(dir= new (&thd->mem_root) String(copy_of_path, length,
+	    !(dir= new (thd->mem_root) String(copy_of_path, length,
 					       &my_charset_bin)) ||
 	    raid_dirs.push_back(dir))
 	  goto err;