MDEV-27188: Suppress optimizer output when executing preparebb-10.7-mdev27188

- Do not write anything into Optimizer Trace at Prepare phase
- When the query gets an error at Prepare phase, make sure there
  is no trace written, either. This is important as we need to
  produce the same trace for "mtr --ps-protocol" and regular mtr run.
- For other kinds of errors, trace is still produced as it might be
  valuable.

(variant 3)

1 files changed, 6 insertions, 0 deletions

diff --git a/sql/opt_trace_context.h b/sql/opt_trace_context.h
index f578a0c67ec..ae77c94fdc2 100644
--- a/sql/opt_trace_context.h
+++ b/sql/opt_trace_context.h
@@ -114,6 +114,12 @@ public:
 
   bool is_enabled();
 
+  void abort_trace()
+  {
+    delete current_trace;
+    current_trace= NULL;
+  }
+
   void missing_privilege();
 
   static const char *flag_names[];