BUG#24860 (Incorrect SLAVE_TRANSACTION_RETRIES code can result in slave stuck):

If a temporary error occured inside a group on an event that was not the first
event of the group, the slave could get stuck because the retry counter is reset
whenever an event was executed successfully.

This patch only reset the retry counter when an entire group has been successfully
executed, or failed with a non-transient error.


sql/slave.cc:
  Adding debug printouts to every place where Relay_log_info::trans_retries
  is changed and to has_temporary_error() to print the error when returning.
  
  Adding debug variable all_errors_are_temporary_errors to make all errors
  for slave thread temporary errors.
  
  Adding code so that the Relay_log_info::trans_retries is only reset when
  an entire group was sucessfully executed, or a non-temporary error occured.
mysql-test/suite/rpl/r/rpl_temporary_errors.result:
  New BitKeeper file ``mysql-test/suite/rpl/r/rpl_temporary_errors.result''
mysql-test/suite/rpl/t/rpl_temporary_errors-slave.opt:
  New BitKeeper file ``mysql-test/suite/rpl/t/rpl_temporary_errors-slave.opt''
mysql-test/suite/rpl/t/rpl_temporary_errors.test:
  New BitKeeper file ``mysql-test/suite/rpl/t/rpl_temporary_errors.test''

1 files changed, 21 insertions, 5 deletions

diff --git a/sql/slave.cc b/sql/slave.cc
index 9780ae70c5b..169cf897e6a 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -1714,7 +1714,14 @@ static int has_temporary_error(THD *thd)
   DBUG_ENTER("has_temporary_error");
 
   if (thd->is_fatal_error)
+  {
+    DBUG_PRINT("info", ("thd->net.last_errno: %s", ER(thd->net.last_errno)));
     DBUG_RETURN(0);
+  }
+
+  DBUG_EXECUTE_IF("all_errors_are_temporary_errors",
+                  if (thd->net.last_errno)
+                    thd->net.last_errno= ER_LOCK_DEADLOCK;);
 
   /*
     Temporary error codes:
@@ -1723,7 +1730,10 @@ static int has_temporary_error(THD *thd)
   */
   if (thd->net.last_errno == ER_LOCK_DEADLOCK ||
       thd->net.last_errno == ER_LOCK_WAIT_TIMEOUT)
+  {
+    DBUG_PRINT("info", ("thd->net.last_errno: %s", ER(thd->net.last_errno)));
     DBUG_RETURN(1);
+  }
 
 #ifdef HAVE_NDB_BINLOG
   /*
@@ -1905,7 +1915,8 @@ static int exec_relay_log_event(THD* thd, Relay_log_info* rli)
     }
     if (slave_trans_retries)
     {
-      if (exec_res && has_temporary_error(thd))
+      int temp_err;
+      if (exec_res && (temp_err= has_temporary_error(thd)))
       {
         const char *errmsg;
         /*
@@ -1953,15 +1964,19 @@ static int exec_relay_log_event(THD* thd, Relay_log_info* rli)
                           "the slave_transaction_retries variable.",
                           slave_trans_retries);
       }
-      else if (!((thd->options & OPTION_BEGIN) && opt_using_transactions))
+      else if (exec_res && !temp_err ||
+               (opt_using_transactions &&
+                rli->group_relay_log_pos == rli->event_relay_log_pos))
       {
         /*
-          Only reset the retry counter if the event succeeded or
-          failed with a non-transient error.  On a successful event,
-          the execution will proceed as usual; in the case of a
+          Only reset the retry counter if the entire group succeeded
+          or failed with a non-transient error.  On a successful
+          event, the execution will proceed as usual; in the case of a
           non-transient error, the slave will stop with an error.
          */
         rli->trans_retries= 0; // restart from fresh
+        DBUG_PRINT("info", ("Resetting retry counter, rli->trans_retries: %d",
+                            rli->trans_retries));
       }
     }
     DBUG_RETURN(exec_res);
@@ -2450,6 +2465,7 @@ pthread_handler_t handle_slave_sql(void *arg)
   rli->ignore_log_space_limit= 0;
   pthread_mutex_unlock(&rli->log_space_lock);
   rli->trans_retries= 0; // start from "no error"
+  DBUG_PRINT("info", ("rli->trans_retries: %d", rli->trans_retries));
 
   if (init_relay_log_pos(rli,
                          rli->group_relay_log_name,