MDEV-5262, MDEV-5914, MDEV-5941, MDEV-6020: Deadlocks during parallel replication causing replication to fail.

Merge the patches into MariaDB 10.0 main.

With this patch, parallel replication will now automatically retry a
transaction that fails due to deadlock or other temporary error, same as
single-threaded replication.

We catch deadlocks with InnoDB transactions due to enforced commit order. If
T1 must commit before T2 in parallel replication and T1 ends up waiting for T2
inside InnoDB, we kill T2 and retry it later to resolve the deadlock
automatically.

1 files changed, 32 insertions, 8 deletions

diff --git a/sql/slave.cc b/sql/slave.cc
index 3d6809b575a..5d6ce9287f2 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -301,7 +301,10 @@ handle_slave_init(void *arg __attribute__((unused)))
   mysql_mutex_lock(&LOCK_thread_count);
   thd->thread_id= thread_id++;
   mysql_mutex_unlock(&LOCK_thread_count);
+  thd->system_thread = SYSTEM_THREAD_SLAVE_INIT;
   thd->store_globals();
+  thd->security_ctx->skip_grants();
+  thd->set_command(COM_DAEMON);
 
   thd_proc_info(thd, "Loading slave GTID position from table");
   if (rpl_load_gtid_slave_state(thd))
@@ -316,15 +319,22 @@ handle_slave_init(void *arg __attribute__((unused)))
   mysql_mutex_unlock(&LOCK_thread_count);
   my_thread_end();
 
-  mysql_mutex_lock(&LOCK_thread_count);
+  mysql_mutex_lock(&LOCK_slave_init);
   slave_init_thread_running= false;
-  mysql_cond_broadcast(&COND_thread_count);
-  mysql_mutex_unlock(&LOCK_thread_count);
+  mysql_cond_broadcast(&COND_slave_init);
+  mysql_mutex_unlock(&LOCK_slave_init);
 
   return 0;
 }
 
 
+/*
+  Start the slave init thread.
+
+  This thread is used to load the GTID state from mysql.gtid_slave_pos at
+  server start; reading from table requires valid THD, which is otherwise not
+  available during server init.
+*/
 static int
 run_slave_init_thread()
 {
@@ -338,10 +348,10 @@ run_slave_init_thread()
     return 1;
   }
 
-  mysql_mutex_lock(&LOCK_thread_count);
+  mysql_mutex_lock(&LOCK_slave_init);
   while (slave_init_thread_running)
-    mysql_cond_wait(&COND_thread_count, &LOCK_thread_count);
-  mysql_mutex_unlock(&LOCK_thread_count);
+    mysql_cond_wait(&COND_slave_init, &LOCK_slave_init);
+  mysql_mutex_unlock(&LOCK_slave_init);
 
   return 0;
 }
@@ -3094,7 +3104,8 @@ static ulong read_event(MYSQL* mysql, Master_info *mi, bool* suppress_warnings)
   that the error is temporary by pushing a warning with the error code
   ER_GET_TEMPORARY_ERRMSG, if the originating error is temporary.
 */
-static int has_temporary_error(THD *thd)
+int
+has_temporary_error(THD *thd)
 {
   DBUG_ENTER("has_temporary_error");
 
@@ -3310,7 +3321,7 @@ int apply_event_and_update_pos(Log_event* ev, THD* thd,
       Make sure we do not errorneously update gtid_slave_pos with a lingering
       GTID from this failed event group (MDEV-4906).
     */
-    rgi->gtid_sub_id= 0;
+    rgi->gtid_pending= false;
   }
 
   DBUG_RETURN(exec_res ? 1 : 0);
@@ -4466,6 +4477,7 @@ pthread_handler_t handle_slave_sql(void *arg)
   mysql_mutex_unlock(&rli->log_space_lock);
 
   serial_rgi->gtid_sub_id= 0;
+  serial_rgi->gtid_pending= false;
   if (init_relay_log_pos(rli,
                          rli->group_relay_log_name,
                          rli->group_relay_log_pos,
@@ -4476,6 +4488,9 @@ pthread_handler_t handle_slave_sql(void *arg)
                 "Error initializing relay log position: %s", errmsg);
     goto err;
   }
+  if (rli->alloc_inuse_relaylog(rli->group_relay_log_name))
+    goto err;
+
   strcpy(rli->future_event_master_log_name, rli->group_master_log_name);
   THD_CHECK_SENTRY(thd);
 #ifndef DBUG_OFF
@@ -6408,6 +6423,7 @@ static Log_event* next_event(rpl_group_info *rgi, ulonglong *event_size)
       DBUG_ASSERT(rli->cur_log_fd >= 0);
       mysql_file_close(rli->cur_log_fd, MYF(MY_WME));
       rli->cur_log_fd = -1;
+      rli->last_inuse_relaylog->completed= true;
 
       if (relay_log_purge)
       {
@@ -6536,6 +6552,12 @@ static Log_event* next_event(rpl_group_info *rgi, ulonglong *event_size)
             mysql_mutex_unlock(log_lock);
           goto err;
         }
+        if (rli->alloc_inuse_relaylog(rli->linfo.log_file_name))
+        {
+          if (!hot_log)
+            mysql_mutex_unlock(log_lock);
+          goto err;
+        }
         if (!hot_log)
           mysql_mutex_unlock(log_lock);
         continue;
@@ -6551,6 +6573,8 @@ static Log_event* next_event(rpl_group_info *rgi, ulonglong *event_size)
       if ((rli->cur_log_fd=open_binlog(cur_log,rli->linfo.log_file_name,
                                        &errmsg)) <0)
         goto err;
+      if (rli->alloc_inuse_relaylog(rli->linfo.log_file_name))
+        goto err;
     }
     else
     {