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



client/mysqltest.c:
  Remove some not needed defines
  (Things like this should be done in config-win.h)
include/config-win.h:
  Added popen() and pclose() compatibility macros
mysql-test/t/rpl_failed_optimize-master.opt:
  Portability fix
sql/ha_berkeley.cc:
  New thd->memroot handling
sql/item_cmpfunc.cc:
  Simpler arena swapping code
sql/item_func.cc:
  Simpler arena swapping code
sql/item_subselect.cc:
  Simpler arena swapping code
  New thd->mem_root handling
sql/item_sum.cc:
  New thd->mem_root handling
sql/item_timefunc.cc:
  Fixed not-initalized usage errors found by valgrind
sql/log_event.cc:
  New thd->mem_root handling
sql/mysql_priv.h:
  New thd->mem_root handling
sql/mysqld.cc:
  New thd->mem_root handling
sql/opt_range.cc:
  New thd->mem_root handling
sql/repl_failsafe.cc:
  New thd->mem_root handling
sql/set_var.cc:
  New thd->mem_root handling
sql/sql_acl.cc:
  New thd->mem_root handling
sql/sql_base.cc:
  Simpler arena swapping code
  New thd->mem_root handling
sql/sql_class.cc:
  New thd->mem_root handling
sql/sql_class.h:
  Simpler arena swapping code
  New thd->mem_root handling
sql/sql_db.cc:
  New thd->mem_root handling
sql/sql_error.cc:
  New thd->mem_root handling
sql/sql_help.cc:
  New thd->mem_root handling
sql/sql_insert.cc:
  New thd->mem_root handling
sql/sql_parse.cc:
  New thd->mem_root handling
  Added some extra checking of return value of new
sql/sql_prepare.cc:
  New thd->mem_root handling
sql/sql_select.cc:
  New thd->mem_root handling
sql/sql_select.h:
  New thd->mem_root handling
sql/sql_union.cc:
  Simpler arena swapping code
sql/sql_yacc.yy:
  New thd->mem_root handling
sql/table.cc:
  New thd->mem_root handling
sql/thr_malloc.cc:
  New thd->mem_root handling
tests/client_test.c:
  Added drop table to some tests
  Changed some table names to 't1'

1 files changed, 3 insertions, 4 deletions

diff --git a/sql/item_func.cc b/sql/item_func.cc
index b382dbf7bf9..bf85e5b378a 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -160,14 +160,13 @@ bool Item_func::agg_arg_charsets(DTCollation &coll,
   }
 
   THD *thd= current_thd;
-  Item_arena *arena= thd->current_arena, backup;
+  Item_arena *arena, backup;
   bool res= FALSE;
   /*
     In case we're in statement prepare, create conversion item
     in its memory: it will be reused on each execute.
   */
-  if (arena->is_stmt_prepare())
-    thd->set_n_backup_item_arena(arena, &backup);
+  arena= thd->change_arena_if_needed(&backup);
 
   for (arg= args, last= args + nargs; arg < last; arg++)
   {
@@ -193,7 +192,7 @@ bool Item_func::agg_arg_charsets(DTCollation &coll,
     conv->fix_fields(thd, 0, &conv);
     *arg= conv;
   }
-  if (arena->is_stmt_prepare())
+  if (arena)
     thd->restore_backup_item_arena(arena, &backup);
   return res;
 }