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, 3 insertions, 3 deletions

diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 4ae69e40342..d81ed2cd014 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -1065,7 +1065,7 @@ static int mysql_test_select(Prepared_statement *stmt,
     DBUG_RETURN(1);
 #endif
 
-  if (!lex->result && !(lex->result= new (&stmt->mem_root) select_send))
+  if (!lex->result && !(lex->result= new (stmt->mem_root) select_send))
   {
     send_error(thd);
     goto err;
@@ -1503,7 +1503,7 @@ static bool init_param_array(Prepared_statement *stmt)
     List_iterator<Item_param> param_iterator(lex->param_list);
     /* Use thd->mem_root as it points at statement mem_root */
     stmt->param_array= (Item_param **)
-                       alloc_root(&stmt->thd->mem_root,
+                       alloc_root(stmt->thd->mem_root,
                                   sizeof(Item_param*) * stmt->param_count);
     if (!stmt->param_array)
     {
@@ -1569,7 +1569,7 @@ int mysql_stmt_prepare(THD *thd, char *packet, uint packet_length,
   if (name)
   {
     stmt->name.length= name->length;
-    if (!(stmt->name.str= memdup_root(&stmt->mem_root, (char*)name->str,
+    if (!(stmt->name.str= memdup_root(stmt->mem_root, (char*)name->str,
                                       name->length)))
     {
       delete stmt;