Don't reset StringBuffers in loops when not needed

- Moved out creating StringBuffers in loops and instead create them
  outside and just reset the buffer if it was not allocated (to avoid
  a possible malloc/free for every entry)

Other things related to set_buffer_if_not_allocated()
- Changed Valuebuffer to not call set_buffer_if_not_allocated() when
  it is created.
- Fixed geometry functions to reset string length before calling
  String::reserve().  This is because one should not access length()
  of an undefined.
- Added Item_func_conv_charset::save_in_field() as the item is using
  str_value to store cached values, which conflicts with
  Item::save_str_in_field().
- Changed Item_proc_string to not store the string value in sql_string
  as this clashes with Item::save_str_in_field().
- Locally store value of full_name_cstring() in analyse::end_of_records()
  as Item::save_str_in_field() may overwrite it.
- Marked some strings as set_thread_specific()
- Added String::free_buffer() to be used internally in String functions
  to just free the buffer but not reset other String values.
- Fixed uses_buffer_owned_by() to check for allocated length instead of
  strlength, which could be marked MEM_UNDEFINED().

1 files changed, 1 insertions, 0 deletions

diff --git a/sql/sp.cc b/sql/sp.cc
index 12fb7e79cde..0b34d75cfec 100644
--- a/sql/sp.cc
+++ b/sql/sp.cc
@@ -960,6 +960,7 @@ Sp_handler::db_load_routine(THD *thd, const Database_qualified_name *name,
   newlex.current_select= NULL;
 
   defstr.set_charset(creation_ctx->get_client_cs());
+  defstr.set_thread_specific();
 
   /*
     We have to add DEFINER clause and provide proper routine characterstics in