First part of fix for BUG#7998 "Replication should be more clever about when...

First part of fix for BUG#7998 "Replication should be more clever about when to replicate RELEASE_LOCK()"
(next part is updating test results)


sql/item_func.cc:
  no need for binlogging DO RELEASE_LOCK() anymore. Make GET_LOCK() do nothing in slave thread.
sql/log_event.cc:
  comment fixes
sql/mysqld.cc:
  warning removed
sql/slave.cc:
  fix after merge

sql/item_func.cc

@@ -2857,18 +2857,6 @@ void item_user_lock_free(void)
 void item_user_lock_release(User_level_lock *ull)
 {
   ull->locked=0;
-  if (mysql_bin_log.is_open())
-  {
-    char buf[256];
-    const char *command="DO RELEASE_LOCK(\"";
-    String tmp(buf,sizeof(buf), system_charset_info);
-    tmp.copy(command, strlen(command), tmp.charset());
-    tmp.append(ull->key,ull->key_length);
-    tmp.append("\")", 2);
-    Query_log_event qev(current_thd, tmp.ptr(), tmp.length(), 0, FALSE);
-    qev.error_code=0; // this query is always safe to run on slave
-    mysql_bin_log.write(&qev);
-  }
   if (--ull->count)
     pthread_cond_signal(&ull->cond);
   else
@@ -2992,6 +2980,16 @@ longlong Item_func_get_lock::val_int()
   User_level_lock *ull;
   int error=0;
 
+  /*
+    In slave thread no need to get locks, everything is serialized. Anyway
+    there is no way to make GET_LOCK() work on slave like it did on master
+    (i.e. make it return exactly the same value) because we don't have the
+    same other concurrent threads environment. No matter what we return here,
+    it's not guaranteed to be same as on master.
+  */
+  if (thd->slave_thread)
+    return 1;
+
   pthread_mutex_lock(&LOCK_user_locks);
 
   if (!res || !res->length())

sql/log_event.cc

@@ -1616,9 +1616,9 @@ Default database: '%s'. Query: '%s'",
     probably, so data_buf will be freed, so the thd->... listed above will be
     pointers to freed memory. 
     So we must set them to 0, so that those bad pointers values are not later
-    used. Note that "cleanup" queries (automatic DO RELEASE_LOCK() and DROP
-    TEMPORARY TABLE don't suffer from these assignments to 0 as DROP TEMPORARY
-    TABLE uses the db.table syntax).
+    used. Note that "cleanup" queries like automatic DROP TEMPORARY TABLE
+    don't suffer from these assignments to 0 as DROP TEMPORARY
+    TABLE uses the db.table syntax.
   */
   thd->db= thd->catalog= 0;	        // prevent db from being freed
   thd->query= 0;			// just to be sure
@@ -3663,8 +3663,8 @@ void Stop_log_event::print(FILE* file, bool short_form, LAST_EVENT_INFO* last_ev
 
   The master stopped.
   We used to clean up all temporary tables but this is useless as, as the
-  master has shut down properly, it has written all DROP TEMPORARY TABLE and DO
-  RELEASE_LOCK (prepared statements' deletion is TODO).
+  master has shut down properly, it has written all DROP TEMPORARY TABLE
+  (prepared statements' deletion is TODO only when we binlog prep stmts).
   We used to clean up slave_load_tmpdir, but this is useless as it has been
   cleared at the end of LOAD DATA INFILE.
   So we have nothing to do here.

sql/mysqld.cc

@@ -5799,7 +5799,7 @@ static void mysql_init_variables(void)
   opt_log= opt_update_log= opt_bin_log= opt_slow_log= 0;
   opt_disable_networking= opt_skip_show_db=0;
   opt_logname= opt_update_logname= opt_binlog_index_name= opt_slow_logname= 0;
-  opt_tc_log_file= "tc.log";      // no hostname in tc_log file name !
+  opt_tc_log_file= (char *)"tc.log";      // no hostname in tc_log file name !
   opt_secure_auth= 0;
   opt_bootstrap= opt_myisam_log= 0;
   mqh_used= 0;

sql/slave.cc

@@ -3257,7 +3257,7 @@ static int exec_relay_log_event(THD* thd, RELAY_LOG_INFO* rli)
           else if (init_relay_log_pos(rli,
                                       rli->group_relay_log_name,
                                       rli->group_relay_log_pos,
-                                      1, &errmsg))
+                                      1, &errmsg, 1))
             sql_print_error("Error initializing relay log position: %s",
                             errmsg);
           else
@@ -3273,16 +3273,7 @@ static int exec_relay_log_event(THD* thd, RELAY_LOG_INFO* rli)
                           slave_trans_retries);
       }
       if (!((thd->options & OPTION_BEGIN) && opt_using_transactions))
-      {
         rli->trans_retries= slave_trans_retries; // restart from fresh
-        /*
-          TODO: when merged into 5.0, when slave does auto-rollback if
-          corrupted binlog, this should reset the retry counter too
-          (any rollback should). In fact it will work, as here we are just out
-          of a Format_description_log_event::exec_event() which rolled back.
-          But check repl code in 5.0 for new ha_rollback calls, just in case.
-        */
-      }
     }
     return exec_res;
   }
@@ -4245,7 +4236,7 @@ int queue_event(MASTER_INFO* mi,const char* buf, ulong event_len)
       master server shutdown. The only thing this does is cleaning. But
       cleaning is already done on a per-master-thread basis (as the master
       server is shutting down cleanly, it has written all DROP TEMPORARY TABLE
-      and DO RELEASE_LOCK; prepared statements' deletion are TODO).
+      prepared statements' deletion are TODO only when we binlog prep stmts).
       
       We don't even increment mi->master_log_pos, because we may be just after
       a Rotate event. Btw, in a few milliseconds we are going to have a Start