slave.cc try_to_reconnect remove retry_counter

`try_to_reconnect()` wraps `safe_reconnect()` with logging, but the latter already loops reconnection attempts up to `master_retry_count` times with `mi->connect_retry`-msec sleeps inbetween. This means `try_to_reconnect()` has been counting disconnects of the replication session (since it doesn’t loop) while `safe_reconnect()` was counting actual tries (which may be multiple per disconnect). In practice, this outer counter’s only benefit was to override the edge case `--master-retry-count=0` that the inner loop doesn’t cover with 1.

Author: ParadoxV5

sql/slave.cc

@@ -112,38 +112,29 @@ enum enum_slave_reconnect_actions
 
 enum enum_slave_reconnect_messages
 {
- SLAVE_RECON_MSG_WAIT= 0,
- SLAVE_RECON_MSG_KILLED_WAITING= 1,
- SLAVE_RECON_MSG_AFTER= 2,
- SLAVE_RECON_MSG_FAILED= 3,
- SLAVE_RECON_MSG_COMMAND= 4,
- SLAVE_RECON_MSG_KILLED_AFTER= 5,
+ SLAVE_RECON_MSG_AFTER,
+ SLAVE_RECON_MSG_FAILED,
+ SLAVE_RECON_MSG_COMMAND,
+ SLAVE_RECON_MSG_KILLED_AFTER,
  SLAVE_RECON_MSG_MAX
 };
 
 static const char *reconnect_messages[SLAVE_RECON_ACT_MAX][SLAVE_RECON_MSG_MAX]=
 {
  {
- "Waiting to reconnect after a failed registration on master",
- "Slave I/O thread killed while waiting to reconnect after a failed \
-registration on master",
  "Reconnecting after a failed registration on master",
  "failed registering on master, reconnecting to try again, \
 log '%s' at position %llu%s",
  "COM_REGISTER_SLAVE",
  "Slave I/O thread killed during or after reconnect"
  },
  {
- "Waiting to reconnect after a failed binlog dump request",
- "Slave I/O thread killed while retrying master dump",
  "Reconnecting after a failed binlog dump request",
  "failed dump request, reconnecting to try again, log '%s' at position %llu%s",
  "COM_BINLOG_DUMP",
  "Slave I/O thread killed during or after reconnect"
  },
  {
- "Waiting to reconnect after a failed master event read",
- "Slave I/O thread killed while waiting to reconnect after a failed read",
  "Reconnecting after a failed master event read",
  "Slave I/O thread: Failed reading log event, reconnecting to retry, \
 log '%s' at position %llu%s",
@@ -4396,20 +4387,18 @@ static bool check_io_slave_killed(Master_info *mi, const char *info)
 /**
  @brief Try to reconnect slave IO thread.
 
- @details Terminates current connection to master, sleeps for
- @c mi->connect_retry msecs and initiates new connection with
- @c safe_reconnect(). Variable pointed by @c retry_count is increased -
+ @details Terminates current connection to master
+ and initiates new connection with safe_reconnect(), which sleeps for
+ @c mi->connect_retry msecs and increases @c mi->TODO for each attempt -
  if it exceeds @c master_retry_count then connection is not re-established
  and function signals error.
  Unless @c suppres_warnings is TRUE, a warning is put in the server error log
  when reconnecting. The warning message and messages used to report errors
- are taken from @c messages array. In case @c master_retry_count is exceeded,
- no messages are added to the log.
+ are taken from @c messages array.
 
  @param[in] thd Thread context.
  @param[in] mysql MySQL connection.
  @param[in] mi Master connection information.
- @param[in,out] retry_count Number of attempts to reconnect.
  @param[in] suppress_warnings TRUE when a normal net read timeout
  has caused to reconnecting.
  @param[in] messages Messages to print/log, see 
@@ -4420,23 +4409,14 @@ static bool check_io_slave_killed(Master_info *mi, const char *info)
 */
 
 static int try_to_reconnect(THD *thd, MYSQL *mysql, Master_info *mi,
- uint *retry_count, bool suppress_warnings,
+ bool suppress_warnings,
  const char *messages[SLAVE_RECON_MSG_MAX])
 {
  mi->slave_running= MYSQL_SLAVE_RUN_NOT_CONNECT;
- thd->proc_info= messages[SLAVE_RECON_MSG_WAIT];
 #ifdef SIGNAL_WITH_VIO_CLOSE 
  thd->clear_active_vio();
 #endif
  end_server(mysql);
- if ((*retry_count)++)
- {
- if (*retry_count > master_retry_count)
- return 1; // Don't retry forever
- slave_sleep(thd, mi->connect_retry, io_slave_killed, mi);
- }
- if (check_io_slave_killed(mi, messages[SLAVE_RECON_MSG_KILLED_WAITING]))
- return 1;
  thd->proc_info = messages[SLAVE_RECON_MSG_AFTER];
  if (!suppress_warnings) 
  {
@@ -4497,7 +4477,6 @@ pthread_handler_t handle_slave_io(void *arg)
  MYSQL *mysql;
  Master_info *mi = (Master_info*)arg;
  Relay_log_info *rli= &mi->rli;
- uint retry_count;
  bool suppress_warnings;
  int ret;
  rpl_io_thread_info io_info;
@@ -4511,7 +4490,6 @@ pthread_handler_t handle_slave_io(void *arg)
 
  DBUG_ASSERT(mi->inited);
  mysql= NULL ;
- retry_count= 0;
 
  thd= new THD(next_thread_id()); // note that contructor of THD uses DBUG_ !
 
@@ -4661,7 +4639,7 @@ pthread_handler_t handle_slave_io(void *arg)
  Try to reconnect because the error was caused by a transient network
  problem
  */
- if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
+ if (try_to_reconnect(thd, mysql, mi, suppress_warnings,
  reconnect_messages[SLAVE_RECON_ACT_REG]))
  goto err;
 
@@ -4678,7 +4656,7 @@ pthread_handler_t handle_slave_io(void *arg)
  "while registering slave on master"))
  {
  sql_print_error("Slave I/O thread couldn't register on master");
- if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
+ if (try_to_reconnect(thd, mysql, mi, suppress_warnings,
  reconnect_messages[SLAVE_RECON_ACT_REG]))
  goto err;
  }
@@ -4705,7 +4683,7 @@ pthread_handler_t handle_slave_io(void *arg)
  {
  sql_print_error("Failed on request_dump()");
  if (check_io_slave_killed(mi, NullS) ||
- try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
+ try_to_reconnect(thd, mysql, mi, suppress_warnings,
  reconnect_messages[SLAVE_RECON_ACT_DUMP]))
  goto err;
  goto connected;
@@ -4764,13 +4742,12 @@ Stopping slave I/O thread due to out-of-memory error from master");
  "%s", ER_THD(thd, ER_OUT_OF_RESOURCES));
  goto err;
  }
- if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
+ if (try_to_reconnect(thd, mysql, mi, suppress_warnings,
  reconnect_messages[SLAVE_RECON_ACT_EVENT]))
  goto err;
  goto connected;
  } // if (event_len == packet_error)
 
- retry_count=0; // ok event, reset retry counter
  thd->set_time_for_next_stage();
  THD_STAGE_INFO(thd, stage_queueing_master_event_to_the_relay_log);
  event_buf= mysql->net.read_pos + 1;