MDEV-11713 Optimize DBUG_PRINT and introduce DBUG_LOG

MariaDB Server is unnecessarily evaluating the arguments of
DBUG_PRINT() macros when the label is not defined.

The macro DBUG_LOG() for C++ operator<< output which was added for
InnoDB diagnostics in MySQL 5.7 is missing from MariaDB. Unlike the
MySQL 5.7 implementation, MariaDB will avoid allocating and
initializing the output string when the label is not defined.

Introduce DBUG_OUT("crypt") and DBUG_OUT("checksum") for some InnoDB
diagnostics, replacing some use of ib::info().

1 files changed, 17 insertions, 18 deletions

diff --git a/dbug/dbug.c b/dbug/dbug.c
index b2b298beb09..048e4803b1a 100644
--- a/dbug/dbug.c
+++ b/dbug/dbug.c
@@ -1213,7 +1213,7 @@ void _db_return_(struct _db_stack_frame_ *_stack_frame_)
  *
  *  SYNOPSIS
  *
- *      VOID _db_pargs_(_line_, keyword)
+ *      int _db_pargs_(_line_, keyword)
  *      int _line_;
  *      char *keyword;
  *
@@ -1226,12 +1226,14 @@ void _db_return_(struct _db_stack_frame_ *_stack_frame_)
  *
  */
 
-void _db_pargs_(uint _line_, const char *keyword)
+int _db_pargs_(uint _line_, const char *keyword)
 {
   CODE_STATE *cs;
-  get_code_state_or_return;
+  get_code_state_or_return 0;
   cs->u_line= _line_;
   cs->u_keyword= keyword;
+
+  return DEBUGGING && _db_keyword_(cs, cs->u_keyword, 0);
 }
 
 
@@ -1265,27 +1267,24 @@ void _db_doprnt_(const char *format,...)
 {
   va_list args;
   CODE_STATE *cs;
+  int save_errno;
+
   get_code_state_or_return;
 
   va_start(args,format);
 
   if (!cs->locked)
     pthread_mutex_lock(&THR_LOCK_dbug);
-  if (_db_keyword_(cs, cs->u_keyword, 0))
-  {
-    int save_errno=errno;
-    DoPrefix(cs, cs->u_line);
-    if (TRACING)
-      Indent(cs, cs->level + 1);
-    else
-      (void) fprintf(cs->stack->out_file->file, "%s: ", cs->func);
-    (void) fprintf(cs->stack->out_file->file, "%s: ", cs->u_keyword);
-    DbugVfprintf(cs->stack->out_file->file, format, args);
-    DbugFlush(cs);
-    errno=save_errno;
-  }
-  else if (!cs->locked)
-    pthread_mutex_unlock(&THR_LOCK_dbug);
+  save_errno=errno;
+  DoPrefix(cs, cs->u_line);
+  if (TRACING)
+    Indent(cs, cs->level + 1);
+  else
+    (void) fprintf(cs->stack->out_file->file, "%s: ", cs->func);
+  (void) fprintf(cs->stack->out_file->file, "%s: ", cs->u_keyword);
+  DbugVfprintf(cs->stack->out_file->file, format, args);
+  DbugFlush(cs);
+  errno=save_errno;
 
   va_end(args);
 }