MDEV-7945 - THD::enter_stage() takes 0.48% in OLTP RO

THD::enter_stage() optimizations:
- stage backup code moved to THD::backup_stage(), saves one condition
- moved check for "new_stage" out to callers that actually need it
- remnants of enter_stage() moved to sql_class.h so it can be inlined

THD::enter_stage() overhead dropped 0.48% -> 0.07%.

PROFILING::status_change() optimizations:
- "status_arg" is now checked by QUERY_PROFILE::new_status()
- no need to check "enabled": !enabled && current is impossible
- remnants of status_change() moved to sql_profile.h so it can be inlined

PROFILING::status_change() overhead dropped 0.1% -> out of radar.

1 files changed, 8 insertions, 1 deletions

diff --git a/sql/sql_profile.h b/sql/sql_profile.h
index f8970bb162a..52eaba49181 100644
--- a/sql/sql_profile.h
+++ b/sql/sql_profile.h
@@ -278,7 +278,14 @@ public:
 
   void status_change(const char *status_arg,
                      const char *function_arg,
-                     const char *file_arg, unsigned int line_arg);
+                     const char *file_arg, unsigned int line_arg)
+  {
+    if (unlikely(current))
+    {
+      DBUG_ASSERT(enabled);
+      current->new_status(status_arg, function_arg, file_arg, line_arg);
+    }
+  }
 
   inline void set_thd(THD *thd_arg) { thd= thd_arg; };