Fix for BUG#8325 "Deadlock in replication thread stops replication":

in slave SQL thread: if a transaction fails because of InnoDB deadlock or innodb_lock_wait_timeout exceeded,
optionally retry the transaction a certain number of times (new variable --slave_transaction_retries).

mysql-test/r/rpl_deadlock.result

+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+create table t1 (a int not null, key(a)) engine=innodb;
+create table t2 (a int not null, key(a)) engine=innodb;
+create table t3 (a int) engine=innodb;
+create table t4 (a int) engine=innodb;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) NOT NULL default '0',
+  KEY `a` (`a`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `a` int(11) NOT NULL default '0',
+  KEY `a` (`a`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+stop slave;
+begin;
+insert into t3 select * from t2 for update;
+insert into t1 values(1);
+commit;
+begin;
+select * from t1 for update;
+a
+start slave;
+insert into t2 values(22);
+commit;
+select * from t1;
+a
+1
+select * from t2;
+a
+22
+show slave status;
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+#	127.0.0.1	root	MASTER_MYPORT	1	master-bin.000001	13110	#	#	master-bin.000001	Yes	Yes							0		0	13110	#	None		0	No						#
+stop slave;
+change master to master_log_pos=401;
+begin;
+select * from t2 for update;
+a
+22
+start slave;
+commit;
+select * from t1;
+a
+1
+1
+select * from t2;
+a
+22
+show slave status;
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+#	127.0.0.1	root	MASTER_MYPORT	1	master-bin.000001	13110	#	#	master-bin.000001	Yes	Yes							0		0	13110	#	None		0	No						#
+set global max_relay_log_size=0;
+stop slave;
+change master to master_log_pos=401;
+begin;
+select * from t2 for update;
+a
+22
+start slave;
+commit;
+select * from t1;
+a
+1
+1
+1
+select * from t2;
+a
+22
+show slave status;
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+#	127.0.0.1	root	MASTER_MYPORT	1	master-bin.000001	13110	#	#	master-bin.000001	Yes	Yes							0		0	13110	#	None		0	No						#
+drop table t1,t2;

mysql-test/t/rpl_deadlock-slave.opt

+--innodb --loose-innodb_lock_wait_timeout=4 --slave-transaction-retries=2 --max-relay-log-size=4096

mysql-test/t/rpl_deadlock.test

+# See if slave restarts the transaction after failing on an InnoDB deadlock error.
+
+# Note: testing what happens when too many retries is possible, but
+# needs large waits when running with --debug, so we don't do it.
+# The same way, this test may not test what is expected when run
+# under Valgrind, timings are too short then (with --valgrind I
+# (Guilhem) have seen the test manage to provoke lock wait timeout
+# error but not deadlock error; that is ok as code deals with the two
+# errors in exactly the same way.
+
+source include/have_innodb.inc;
+source include/master-slave.inc;
+
+connection master;
+create table t1 (a int not null, key(a)) engine=innodb;
+create table t2 (a int not null, key(a)) engine=innodb;
+create table t3 (a int) engine=innodb;
+create table t4 (a int) engine=innodb;
+sync_slave_with_master;
+
+show create table t1;
+show create table t2;
+stop slave;
+
+# 1) Test deadlock
+
+connection master;
+begin;
+# Let's keep BEGIN and the locked statement in two different relay logs.
+let $1=200;
+disable_query_log;
+while ($1)
+{
+ eval insert into t3 values( $1 );
+ dec $1;
+}
+enable_query_log;
+insert into t3 select * from t2 for update;
+insert into t1 values(1);
+commit;
+save_master_pos;
+
+connection slave;
+begin;
+# Let's make our transaction large so that it's slave who is chosen as
+# victim
+let $1=1000;
+disable_query_log;
+while ($1)
+{
+ eval insert into t4 values( $1 );
+ dec $1;
+}
+enable_query_log;
+select * from t1 for update;
+start slave;
+--sleep 3; # hope that slave is blocked now
+insert into t2 values(22); # provoke deadlock, slave should be victim
+commit;
+sync_with_master;
+select * from t1; # check that slave succeeded finally
+select * from t2;
+# check that no error is reported
+--replace_column 1 # 8 # 9 # 23 # 33 #
+--replace_result $MASTER_MYPORT MASTER_MYPORT
+show slave status;
+
+# 2) Test lock wait timeout
+
+stop slave;
+change master to master_log_pos=401; # the BEGIN log event
+begin;
+select * from t2 for update; # hold lock
+start slave;
+--sleep 10; # slave should have blocked, and be retrying
+commit;
+sync_with_master;
+select * from t1; # check that slave succeeded finally
+select * from t2;
+# check that no error is reported
+--replace_column 1 # 8 # 9 # 23 # 33 #
+--replace_result $MASTER_MYPORT MASTER_MYPORT
+show slave status;
+
+# Now we repeat 2), but with BEGIN in the same relay log as
+# COMMIT (to see if seeking into hot log is ok).
+
+set global max_relay_log_size=0;
+
+# This is really copy-paste of 2) of above
+stop slave;
+change master to master_log_pos=401;
+begin;
+select * from t2 for update;
+start slave;
+--sleep 10;
+commit;
+sync_with_master;
+select * from t1;
+select * from t2;
+--replace_column 1 # 8 # 9 # 23 # 33 #
+--replace_result $MASTER_MYPORT MASTER_MYPORT
+show slave status;
+
+connection master;
+drop table t1,t2;
+sync_slave_with_master;

sql/mysql_priv.h

@@ -890,7 +890,7 @@ extern ulong ha_read_first_count, ha_read_last_count;
 extern ulong ha_read_rnd_count, ha_read_rnd_next_count, ha_discover_count;
 extern ulong ha_commit_count, ha_rollback_count,table_cache_size;
 extern ulong max_connections,max_connect_errors, connect_timeout;
-extern ulong slave_net_timeout;
+extern ulong slave_net_timeout, slave_trans_retries;
 extern ulong max_user_connections;
 extern ulong long_query_count, what_to_log,flush_time;
 extern ulong query_buff_size, thread_stack,thread_stack_min;

sql/mysqld.cc

@@ -311,7 +311,7 @@ ulong server_id, thd_startup_options;
 ulong table_cache_size, thread_stack, thread_stack_min, what_to_log;
 ulong query_buff_size, slow_launch_time, slave_open_temp_tables;
 ulong open_files_limit, max_binlog_size, max_relay_log_size;
-ulong slave_net_timeout;
+ulong slave_net_timeout, slave_trans_retries;
 ulong thread_cache_size=0, binlog_cache_size=0, max_binlog_cache_size=0;
 ulong query_cache_size=0;
 ulong com_stat[(uint) SQLCOM_END], com_other;
@@ -4096,7 +4096,7 @@ enum options_mysqld
   OPT_QUERY_CACHE_TYPE, OPT_QUERY_CACHE_WLOCK_INVALIDATE, OPT_RECORD_BUFFER,
   OPT_RECORD_RND_BUFFER, OPT_RELAY_LOG_SPACE_LIMIT, OPT_RELAY_LOG_PURGE,
   OPT_SLAVE_NET_TIMEOUT, OPT_SLAVE_COMPRESSED_PROTOCOL, OPT_SLOW_LAUNCH_TIME,
-  OPT_READONLY, OPT_DEBUGGING,
+  OPT_SLAVE_TRANS_RETRIES, OPT_READONLY, OPT_DEBUGGING,
   OPT_SORT_BUFFER, OPT_TABLE_CACHE,
   OPT_THREAD_CONCURRENCY, OPT_THREAD_CACHE_SIZE,
   OPT_TMP_TABLE_SIZE, OPT_THREAD_STACK,
@@ -5049,7 +5049,7 @@ The minimum value for this variable is 4096.",
     (gptr*) &max_system_variables.max_length_for_sort_data, 0, GET_ULONG,
     REQUIRED_ARG, 1024, 4, 8192*1024L, 0, 1, 0},
   {"max_relay_log_size", OPT_MAX_RELAY_LOG_SIZE,
-   "If non-zero: relay log will be rotated automatically when the size exceeds this value; if zero (the default): when the size exceeds max_binlog_size. 0 expected, the minimum value for this variable is 4096.",
+   "If non-zero: relay log will be rotated automatically when the size exceeds this value; if zero (the default): when the size exceeds max_binlog_size. 0 excepted, the minimum value for this variable is 4096.",
    (gptr*) &max_relay_log_size, (gptr*) &max_relay_log_size, 0, GET_ULONG,
    REQUIRED_ARG, 0L, 0L, 1024*1024L*1024L, 0, IO_SIZE, 0},
   { "max_seeks_for_key", OPT_MAX_SEEKS_FOR_KEY,
@@ -5220,6 +5220,12 @@ The minimum value for this variable is 4096.",
    "Number of seconds to wait for more data from a master/slave connection before aborting the read.",
    (gptr*) &slave_net_timeout, (gptr*) &slave_net_timeout, 0,
    GET_ULONG, REQUIRED_ARG, SLAVE_NET_TIMEOUT, 1, LONG_TIMEOUT, 0, 1, 0},
+  {"slave_transaction_retries", OPT_SLAVE_TRANS_RETRIES,
+   "Number of times the slave SQL thread will retry a transaction in case "
+   "it failed with a deadlock or elapsed lock wait timeout, "
+   "before giving up and stopping.",
+   (gptr*) &slave_trans_retries, (gptr*) &slave_trans_retries, 0,
+   GET_ULONG, REQUIRED_ARG, 0L, 0L, (longlong) ULONG_MAX, 0, 1, 0},
 #endif /* HAVE_REPLICATION */
   {"slow_launch_time", OPT_SLOW_LAUNCH_TIME,
    "If creating the thread takes longer than this value (in seconds), the Slow_launch_threads counter will be incremented.",

sql/set_var.cc

@@ -320,6 +320,8 @@ sys_var_bool_ptr	sys_slave_compressed_protocol("slave_compressed_protocol",
 #ifdef HAVE_REPLICATION
 sys_var_long_ptr	sys_slave_net_timeout("slave_net_timeout",
 					      &slave_net_timeout);
+sys_var_long_ptr	sys_slave_trans_retries("slave_transaction_retries",
+                                                &slave_trans_retries);
 #endif
 sys_var_long_ptr	sys_slow_launch_time("slow_launch_time",
 					     &slow_launch_time);
@@ -604,6 +606,7 @@ sys_var *sys_variables[]=
 #ifdef HAVE_REPLICATION
   &sys_slave_compressed_protocol,
   &sys_slave_net_timeout,
+  &sys_slave_trans_retries,
   &sys_slave_skip_counter,
 #endif
   &sys_slow_launch_time,
@@ -855,6 +858,7 @@ struct show_var_st init_vars[]= {
   {"skip_show_database",      (char*) &opt_skip_show_db,            SHOW_BOOL},
 #ifdef HAVE_REPLICATION
   {sys_slave_net_timeout.name,(char*) &sys_slave_net_timeout,	    SHOW_SYS},
+  {sys_slave_trans_retries.name,(char*) &sys_slave_trans_retries,   SHOW_SYS},
 #endif
   {sys_slow_launch_time.name, (char*) &sys_slow_launch_time,        SHOW_SYS},
 #ifdef HAVE_SYS_UN_H

sql/slave.cc

@@ -2959,6 +2959,62 @@ static int exec_relay_log_event(THD* thd, RELAY_LOG_INFO* rli)
     exec_res = ev->exec_event(rli);
     DBUG_ASSERT(rli->sql_thd==thd);
     delete ev;
+    if (slave_trans_retries)
+    {
+      if (exec_res &&
+          (thd->net.last_errno == ER_LOCK_DEADLOCK ||
+           thd->net.last_errno == ER_LOCK_WAIT_TIMEOUT) &&
+          !thd->is_fatal_error)
+      {
+        const char *errmsg;
+        /*
+          We were in a transaction which has been rolled back because of a
+          deadlock (currently, InnoDB deadlock detected by InnoDB) or lock
+          wait timeout (innodb_lock_wait_timeout exceeded); let's seek back to
+          BEGIN log event and retry it all again.
+          We have to not only seek but also
+          a) init_master_info(), to seek back to hot relay log's start for later
+          (for when we will come back to this hot log after re-processing the
+          possibly existing old logs where BEGIN is: check_binlog_magic() will
+          then need the cache to be at position 0 (see comments at beginning of
+          init_master_info()).
+          b) init_relay_log_pos(), because the BEGIN may be an older relay log.
+        */
+        if (rli->trans_retries--)
+        {
+          sql_print_information("Slave SQL thread retries transaction");
+          if (init_master_info(rli->mi, 0, 0, 0, SLAVE_SQL))
+            sql_print_error("Failed to initialize the master info structure");
+          else if (init_relay_log_pos(rli,
+                                      rli->group_relay_log_name,
+                                      rli->group_relay_log_pos,
+                                      1, &errmsg))
+            sql_print_error("Error initializing relay log position: %s",
+                            errmsg);
+          else
+          {
+            exec_res= 0;
+            sleep(2); // chance for concurrent connection to get more locks
+          }
+        }
+        else
+          sql_print_error("Slave SQL thread retried transaction %lu time(s) "
+                          "in vain, giving up. Consider raising the value of "
+                          "the slave_transaction_retries variable.",
+                          slave_trans_retries);
+      }
+      if (!((thd->options & OPTION_BEGIN) && opt_using_transactions))
+      {
+        rli->trans_retries= slave_trans_retries; // restart from fresh
+        /*
+          TODO: when merged into 5.0, when slave does auto-rollback if
+          corrupted binlog, this should reset the retry counter too
+          (any rollback should). In fact it will work, as here we are just out
+          of a Format_description_log_event::exec_event() which rolled back.
+          But check repl code in 5.0 for new ha_rollback calls, just in case.
+        */
+      }
+    }
     return exec_res;
   }
   else
@@ -3370,6 +3426,7 @@ extern "C" pthread_handler_decl(handle_slave_sql,arg)
   pthread_mutex_lock(&rli->log_space_lock);
   rli->ignore_log_space_limit= 0;
   pthread_mutex_unlock(&rli->log_space_lock);
+  rli->trans_retries= slave_trans_retries; // start from "no error"
 
   if (init_relay_log_pos(rli,
 			 rli->group_relay_log_name,

sql/slave.h

@@ -295,6 +295,8 @@ typedef struct st_relay_log_info
     UNTIL_LOG_NAMES_CMP_EQUAL= 0, UNTIL_LOG_NAMES_CMP_GREATER= 1
   } until_log_names_cmp_result;
 
+  ulong trans_retries;
+
   st_relay_log_info();
   ~st_relay_log_info();