fix memory during MYSQL_BIN_LOG::open_existing_binlog

Summary:
asandebug complain there are memory leaks during MYSQL_BIN_LOG open

Direct leak of 50 byte(s) in 1 object(s) allocated from:
    #0 0x67460ef in malloc
    #1 0x93f0777 in my_raw_malloc(unsigned long, int)
    #2 0x93f064a in my_malloc(unsigned int, unsigned long, int)
    #3 0x93f0eb0 in my_strdup(unsigned int, char const*, int)
    #4 0x8af01a6 in MYSQL_BIN_LOG::open(unsigned int, char const*, char const*, unsigned int)
    #5 0x8af8064 in MYSQL_BIN_LOG::open_binlog(char const*, char const*, unsigned long, bool, bool, bool, Format_description_log_event*, unsigned int, RaftRotateInfo*, bool)
    #6 0x8b00c00 in MYSQL_BIN_LOG::new_file_impl(bool, Format_description_log_event*, RaftRotateInfo*)
    #7 0x8d65e47 in rotate_relay_log(Master_info*, bool, bool, bool, RaftRotateInfo*)
    #8 0x8d661c0 in rotate_relay_log_for_raft(RaftRotateInfo*)
    #9 0x8c7696a in process_raft_queue
    #10 0xa0fa1fd in pfs_spawn_thread(void*)
    #11 0x7f8c9a12b20b in start_thread

release these memory before assign them

Reviewed By: Pushapgl

Differential Revision: D28819752

fbshipit-source-id: ed57cea875c

sql/binlog.cc

@@ -6342,8 +6342,8 @@ bool MYSQL_BIN_LOG::open_existing_binlog(const char *log_name,
     DBUG_RETURN(1);
   }
 
-  if (!(this->name =
-            my_strdup(key_memory_MYSQL_LOG_name, log_name, MYF(MY_WME)))) {
+  my_free(name);
+  if (!(name = my_strdup(key_memory_MYSQL_LOG_name, log_name, MYF(MY_WME)))) {
     // NO_LINT_DEBUG
     sql_print_error("Could not allocate name %s (error %d)", log_name, errno);
     DBUG_RETURN(1);
@@ -6353,6 +6353,8 @@ bool MYSQL_BIN_LOG::open_existing_binlog(const char *log_name,
       Binlog_ofile::open_existing(m_key_file_log, existing_file, MYF(MY_WME));
   if (!binlog_file) goto err;
 
+  // release current point before assign
+  delete m_binlog_file;
   m_binlog_file = binlog_file.release();
 
   file = mysql_file_open(m_key_file_log, existing_file, O_CREAT | O_WRONLY,

sql/log_event.cc

@@ -4731,17 +4731,15 @@ int Query_log_event::do_apply_event(Relay_log_info const *rli) {
 }
 
 int Query_log_event::do_apply_event_worker(Slave_worker *w) {
-  if (ends_group()) {
-    // Note: We're using event's future_event_relay_log_pos instead of
-    // rli->get_event_relay_log_pos() because rli is only updated in
-    // do_update_pos() which is called after applying the event and we might
-    // need to use this pos during application (e.g. during commit)
-    Slave_job_group *ptr_g = w->c_rli->gaq->get_job_group(mts_group_idx);
-    thd->set_trans_relay_log_pos(ptr_g->group_relay_log_name
-                                     ? ptr_g->group_relay_log_name
-                                     : w->get_group_relay_log_name(),
-                                 future_event_relay_log_pos);
-  }
+  // Note: We're using event's future_event_relay_log_pos instead of
+  // rli->get_event_relay_log_pos() because rli is only updated in
+  // do_update_pos() which is called after applying the event and we might
+  // need to use this pos during application (e.g. during commit)
+  Slave_job_group *ptr_g = w->c_rli->gaq->get_job_group(mts_group_idx);
+  thd->set_trans_relay_log_pos(ptr_g->group_relay_log_name
+                                   ? ptr_g->group_relay_log_name
+                                   : w->get_group_relay_log_name(),
+                               future_event_relay_log_pos);
   return do_apply_event(w, query, q_len);
 }