diff options
Diffstat (limited to 'sql/slave.cc')
| -rw-r--r-- | sql/slave.cc | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/sql/slave.cc b/sql/slave.cc index be95cc16d90..21674d9ece2 100644 --- a/sql/slave.cc +++ b/sql/slave.cc @@ -1388,9 +1388,7 @@ static bool wait_for_relay_log_space(RELAY_LOG_INFO* rli) while (rli->log_space_limit < rli->log_space_total && !(slave_killed=io_slave_killed(thd,mi)) && !rli->ignore_log_space_limit) - { pthread_cond_wait(&rli->log_space_cond, &rli->log_space_lock); - } thd->proc_info = save_proc_info; pthread_mutex_unlock(&rli->log_space_lock); DBUG_RETURN(slave_killed); @@ -2101,7 +2099,11 @@ static int exec_relay_log_event(THD* thd, RELAY_LOG_INFO* rli) Log_event * ev = next_event(rli); DBUG_ASSERT(rli->sql_thd==thd); if (sql_slave_killed(thd,rli)) + { + /* do not forget to free ev ! */ + if (ev) delete ev; return 1; + } if (ev) { int type_code = ev->get_type_code(); @@ -2376,6 +2378,18 @@ reconnect done to recover from failed read"); goto err; } flush_master_info(mi); + /* + See if the relay logs take too much space. + We don't lock mi->rli.log_space_lock here; this dirty read saves time + and does not introduce any problem: + - if mi->rli.ignore_log_space_limit is 1 but becomes 0 just after (so + the clean value is 0), then we are reading only one more event as we + should, and we'll block only at the next event. No big deal. + - if mi->rli.ignore_log_space_limit is 0 but becomes 1 just after (so + the clean value is 1), then we are going into wait_for_relay_log_space() + for no reason, but this function will do a clean read, notice the clean + value and exit immediately. + */ if (mi->rli.log_space_limit && mi->rli.log_space_limit < mi->rli.log_space_total && !mi->rli.ignore_log_space_limit) @@ -2489,7 +2503,9 @@ slave_begin: pthread_cond_broadcast(&rli->start_cond); //tell the I/O thread to take relay_log_space_limit into account from now on + pthread_mutex_lock(&rli->log_space_lock); rli->ignore_log_space_limit= 0; + pthread_mutex_unlock(&rli->log_space_lock); if (init_relay_log_pos(rli, rli->group_relay_log_name, @@ -3221,7 +3237,12 @@ Log_event* next_event(RELAY_LOG_INFO* rli) pthread_mutex_lock(&rli->log_space_lock); // prevent the I/O thread from blocking next times rli->ignore_log_space_limit= 1; - // If the I/O thread is blocked, unblock it + /* + If the I/O thread is blocked, unblock it. + Ok to broadcast after unlock, because the mutex is only destroyed in + ~st_relay_log_info(), i.e. when rli is destroyed, and rli will not be + destroyed before we exit the present function. + */ pthread_mutex_unlock(&rli->log_space_lock); pthread_cond_broadcast(&rli->log_space_cond); // Note that wait_for_update unlocks lock_log ! |