Added DBUG_ASSERT_AS_PRINTF compile flag

If compiling a non DBUG binary with
-DDBUG_ASSERT_AS_PRINTF asserts will be
changed to printf + stack trace (of stack
trace are enabled).

- Changed #ifndef DBUG_OFF to
  #ifdef DBUG_ASSERT_EXISTS
  for those DBUG_OFF that was just used to enable
  assert
- Assert checking that could greatly impact
  performance where changed to DBUG_ASSERT_SLOW which
  is not affected by DBUG_ASSERT_AS_PRINTF
- Added one extra option to my_print_stacktrace() to
  get more silent in case of stack trace printing as
  part of assert.

1 files changed, 1 insertions, 1 deletions

diff --git a/mysys/thr_lock.c b/mysys/thr_lock.c
index 6cb9d6af13d..56ac5298da7 100644
--- a/mysys/thr_lock.c
+++ b/mysys/thr_lock.c
@@ -1541,7 +1541,7 @@ void thr_downgrade_write_lock(THR_LOCK_DATA *in_data,
                               enum thr_lock_type new_lock_type)
 {
   THR_LOCK *lock=in_data->lock;
-#ifndef DBUG_OFF
+#ifdef DBUG_ASSERT_EXISTS
   enum thr_lock_type old_lock_type= in_data->type;
 #endif
   DBUG_ENTER("thr_downgrade_write_only_lock");