revision-id: cb06612a9da09a7981ada84768793f2ff3ef842c
(mariadb-10.4.30-3-gcb06612a9da)
parent(s): dbe5c20b755b87f67d87990c3baabc866667e41b
author: Kristian Nielsen
committer: Kristian Nielsen
timestamp: 2023-07-11 00:31:29 +0200
message:
MDEV-31655: Parallel replication deadlock victim preference code errorneously
removed
Restore code to make InnoDB choose the second transaction as a deadlock
victim if two transactions deadlock that need to commit in-order for
parallel replication. This code was erroneously removed when VATS was
implemented in InnoDB.
Also add a test case for InnoDB choosing the right deadlock victim.
Signed-off-by: Kristian Nielsen <kniel...@knielsen-hq.org>
---
.../suite/binlog_encryption/rpl_parallel.result | 42 ++++++++++++-
mysql-test/suite/rpl/r/rpl_parallel.result | 42 ++++++++++++-
mysql-test/suite/rpl/t/rpl_parallel.test | 71 +++++++++++++++++++++-
sql/rpl_parallel.cc | 7 ++-
sql/sql_class.cc | 43 +++++++++++++
storage/innobase/lock/lock0lock.cc | 12 ++++
storage/innobase/trx/trx0trx.cc | 12 ++++
7 files changed, 225 insertions(+), 4 deletions(-)
diff --git a/mysql-test/suite/binlog_encryption/rpl_parallel.result
b/mysql-test/suite/binlog_encryption/rpl_parallel.result
index b75a66a634a..b24ff7ba53d 100644
--- a/mysql-test/suite/binlog_encryption/rpl_parallel.result
+++ b/mysql-test/suite/binlog_encryption/rpl_parallel.result
@@ -2,6 +2,7 @@ include/master-slave.inc
[connection master]
connection server_2;
SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
+SET @old_parallel_mode=@@GLOBAL.slave_parallel_mode;
SET GLOBAL slave_parallel_threads=10;
ERROR HY000: This operation cannot be performed as you have a running slave
''; run STOP SLAVE '' first
include/stop_slave.inc
@@ -1680,13 +1681,52 @@ a
2000
SELECT * FROM t2 WHERE a>=2000 ORDER BY a;
a
+MDEV-31655: Parallel replication deadlock victim preference code erroneously
removed
+connection server_1;
+CREATE TABLE t7 (a INT PRIMARY KEY, b INT) ENGINE=InnoDB;
+BEGIN;
+COMMIT;
+include/save_master_gtid.inc
+connection server_2;
+include/sync_with_master_gtid.inc
+include/stop_slave.inc
+set @@global.slave_parallel_threads= 5;
+set @@global.slave_parallel_mode= conservative;
+SET @old_dbug= @@GLOBAL.debug_dbug;
+SET GLOBAL debug_dbug= "+d,rpl_mdev31655_zero_retries";
+connection master;
+SET @old_dbug= @@SESSION.debug_dbug;
+SET SESSION debug_dbug="+d,binlog_force_commit_id";
+SET @commit_id= 1+1000;
+SET @commit_id= 2+1000;
+SET @commit_id= 3+1000;
+SET @commit_id= 4+1000;
+SET @commit_id= 5+1000;
+SET @commit_id= 6+1000;
+SET @commit_id= 7+1000;
+SET @commit_id= 8+1000;
+SET @commit_id= 9+1000;
+SET @commit_id= 10+1000;
+SET SESSION debug_dbug= @old_dbug;
+SELECT COUNT(*), SUM(a*100*b) FROM t7;
+COUNT(*) SUM(a*100*b)
+10 225000
+include/save_master_gtid.inc
+connection server_2;
+include/start_slave.inc
+include/sync_with_master_gtid.inc
+SET GLOBAL debug_dbug= @old_dbug;
+SELECT COUNT(*), SUM(a*100*b) FROM t7;
+COUNT(*) SUM(a*100*b)
+10 225000
connection server_2;
include/stop_slave.inc
SET GLOBAL slave_parallel_threads=@old_parallel_threads;
+SET GLOBAL slave_parallel_mode=@old_parallel_mode;
include/start_slave.inc
SET DEBUG_SYNC= 'RESET';
connection server_1;
DROP function foo;
-DROP TABLE t1,t2,t3,t4,t5,t6;
+DROP TABLE t1,t2,t3,t4,t5,t6,t7;
SET DEBUG_SYNC= 'RESET';
include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_parallel.result
b/mysql-test/suite/rpl/r/rpl_parallel.result
index 9b2e68d366e..ef89d954faa 100644
--- a/mysql-test/suite/rpl/r/rpl_parallel.result
+++ b/mysql-test/suite/rpl/r/rpl_parallel.result
@@ -2,6 +2,7 @@ include/master-slave.inc
[connection master]
connection server_2;
SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
+SET @old_parallel_mode=@@GLOBAL.slave_parallel_mode;
SET GLOBAL slave_parallel_threads=10;
ERROR HY000: This operation cannot be performed as you have a running slave
''; run STOP SLAVE '' first
include/stop_slave.inc
@@ -1679,13 +1680,52 @@ a
2000
SELECT * FROM t2 WHERE a>=2000 ORDER BY a;
a
+MDEV-31655: Parallel replication deadlock victim preference code erroneously
removed
+connection server_1;
+CREATE TABLE t7 (a INT PRIMARY KEY, b INT) ENGINE=InnoDB;
+BEGIN;
+COMMIT;
+include/save_master_gtid.inc
+connection server_2;
+include/sync_with_master_gtid.inc
+include/stop_slave.inc
+set @@global.slave_parallel_threads= 5;
+set @@global.slave_parallel_mode= conservative;
+SET @old_dbug= @@GLOBAL.debug_dbug;
+SET GLOBAL debug_dbug= "+d,rpl_mdev31655_zero_retries";
+connection master;
+SET @old_dbug= @@SESSION.debug_dbug;
+SET SESSION debug_dbug="+d,binlog_force_commit_id";
+SET @commit_id= 1+1000;
+SET @commit_id= 2+1000;
+SET @commit_id= 3+1000;
+SET @commit_id= 4+1000;
+SET @commit_id= 5+1000;
+SET @commit_id= 6+1000;
+SET @commit_id= 7+1000;
+SET @commit_id= 8+1000;
+SET @commit_id= 9+1000;
+SET @commit_id= 10+1000;
+SET SESSION debug_dbug= @old_dbug;
+SELECT COUNT(*), SUM(a*100*b) FROM t7;
+COUNT(*) SUM(a*100*b)
+10 225000
+include/save_master_gtid.inc
+connection server_2;
+include/start_slave.inc
+include/sync_with_master_gtid.inc
+SET GLOBAL debug_dbug= @old_dbug;
+SELECT COUNT(*), SUM(a*100*b) FROM t7;
+COUNT(*) SUM(a*100*b)
+10 225000
connection server_2;
include/stop_slave.inc
SET GLOBAL slave_parallel_threads=@old_parallel_threads;
+SET GLOBAL slave_parallel_mode=@old_parallel_mode;
include/start_slave.inc
SET DEBUG_SYNC= 'RESET';
connection server_1;
DROP function foo;
-DROP TABLE t1,t2,t3,t4,t5,t6;
+DROP TABLE t1,t2,t3,t4,t5,t6,t7;
SET DEBUG_SYNC= 'RESET';
include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_parallel.test
b/mysql-test/suite/rpl/t/rpl_parallel.test
index 9ba7a30f2eb..d43cec4df34 100644
--- a/mysql-test/suite/rpl/t/rpl_parallel.test
+++ b/mysql-test/suite/rpl/t/rpl_parallel.test
@@ -13,6 +13,7 @@
--connection server_2
SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
+SET @old_parallel_mode=@@GLOBAL.slave_parallel_mode;
--error ER_SLAVE_MUST_STOP
SET GLOBAL slave_parallel_threads=10;
--source include/stop_slave.inc
@@ -2203,16 +2204,84 @@ SELECT * FROM t1 WHERE a>=2000 ORDER BY a;
SELECT * FROM t2 WHERE a>=2000 ORDER BY a;
+--echo MDEV-31655: Parallel replication deadlock victim preference code
erroneously removed
+# The problem was that InnoDB would choose the wrong deadlock victim.
+# Create a lot of transactions that can cause deadlocks, and use error
+# injection to check that the first transactions in each group is never
+# selected as deadlock victim.
+--let $rows= 10
+--let $transactions= 5
+--let $gcos= 10
+
+--connection server_1
+CREATE TABLE t7 (a INT PRIMARY KEY, b INT) ENGINE=InnoDB;
+BEGIN;
+--disable_query_log
+--let $i= 0
+while ($i < 10) {
+ eval INSERT INTO t7 VALUES ($i, 0);
+ inc $i;
+}
+--enable_query_log
+COMMIT;
+--source include/save_master_gtid.inc
+
+--connection server_2
+--source include/sync_with_master_gtid.inc
+--source include/stop_slave.inc
+eval set @@global.slave_parallel_threads= $transactions;
+set @@global.slave_parallel_mode= conservative;
+SET @old_dbug= @@GLOBAL.debug_dbug;
+# This error injection will allow no retries for GTIDs divisible by 1000.
+SET GLOBAL debug_dbug= "+d,rpl_mdev31655_zero_retries";
+
+--connection master
+SET @old_dbug= @@SESSION.debug_dbug;
+SET SESSION debug_dbug="+d,binlog_force_commit_id";
+
+--let $j= 1
+while ($j <= $gcos) {
+ eval SET @commit_id= $j+1000;
+ --let $i= 0
+ while ($i < $transactions) {
+ --disable_query_log
+ eval SET SESSION gtid_seq_no= 1000 + 1000*$j + $i;
+ BEGIN;
+ --let $k= 0
+ while ($k < $rows) {
+ eval UPDATE t7 SET b=b+1 WHERE a=(($i+$k) MOD $rows);
+ inc $k;
+ }
+ COMMIT;
+ --enable_query_log
+ inc $i;
+ }
+ inc $j;
+}
+
+SET SESSION debug_dbug= @old_dbug;
+SELECT COUNT(*), SUM(a*100*b) FROM t7;
+
+--source include/save_master_gtid.inc
+
+--connection server_2
+--source include/start_slave.inc
+--source include/sync_with_master_gtid.inc
+SET GLOBAL debug_dbug= @old_dbug;
+SELECT COUNT(*), SUM(a*100*b) FROM t7;
+
+
# Clean up.
--connection server_2
--source include/stop_slave.inc
SET GLOBAL slave_parallel_threads=@old_parallel_threads;
+SET GLOBAL slave_parallel_mode=@old_parallel_mode;
--source include/start_slave.inc
SET DEBUG_SYNC= 'RESET';
--connection server_1
DROP function foo;
-DROP TABLE t1,t2,t3,t4,t5,t6;
+DROP TABLE t1,t2,t3,t4,t5,t6,t7;
SET DEBUG_SYNC= 'RESET';
--source include/rpl_end.inc
diff --git a/sql/rpl_parallel.cc b/sql/rpl_parallel.cc
index b550315d69f..1aeb1257c4a 100644
--- a/sql/rpl_parallel.cc
+++ b/sql/rpl_parallel.cc
@@ -1385,8 +1385,13 @@ handle_rpl_parallel_thread(void *arg)
err= dbug_simulate_tmp_error(rgi, thd););
if (unlikely(err))
{
+ ulong max_retries= slave_trans_retries;
convert_kill_to_deadlock_error(rgi);
- if (has_temporary_error(thd) && slave_trans_retries > 0)
+ DBUG_EXECUTE_IF("rpl_mdev31655_zero_retries",
+ if ((rgi->current_gtid.seq_no % 1000) == 0)
+ max_retries= 0;
+ );
+ if (has_temporary_error(thd) && max_retries > 0)
err= retry_event_group(rgi, rpt, qev);
}
}
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 8ed3f8a9c5e..e6ed7ca1cc4 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -5247,6 +5247,49 @@ thd_need_ordering_with(const MYSQL_THD thd, const
MYSQL_THD other_thd)
return 0;
}
+
+/*
+ If the storage engine detects a deadlock, and needs to choose a victim
+ transaction to roll back, it can call this function to ask the upper
+ server layer for which of two possible transactions is prefered to be
+ aborted and rolled back.
+
+ In parallel replication, if two transactions are running in parallel and
+ one is fixed to commit before the other, then the one that commits later
+ will be prefered as the victim - chosing the early transaction as a victim
+ will not resolve the deadlock anyway, as the later transaction still needs
+ to wait for the earlier to commit.
+
+ The return value is -1 if the first transaction is prefered as a deadlock
+ victim, 1 if the second transaction is prefered, or 0 for no preference (in
+ which case the storage engine can make the choice as it prefers).
+*/
+extern "C" int
+thd_deadlock_victim_preference(const MYSQL_THD thd1, const MYSQL_THD thd2)
+{
+ rpl_group_info *rgi1, *rgi2;
+
+ if (!thd1 || !thd2)
+ return 0;
+
+ /*
+ If the transactions are participating in the same replication domain in
+ parallel replication, then request to select the one that will commit
+ later (in the fixed commit order from the master) as the deadlock victim.
+ */
+ rgi1= thd1->rgi_slave;
+ rgi2= thd2->rgi_slave;
+ if (rgi1 && rgi2 &&
+ rgi1->is_parallel_exec &&
+ rgi1->rli == rgi2->rli &&
+ rgi1->current_gtid.domain_id == rgi2->current_gtid.domain_id)
+ return rgi1->gtid_sub_id < rgi2->gtid_sub_id ? 1 : -1;
+
+ /* No preferences, let the storage engine decide. */
+ return 0;
+}
+
+
extern "C" int thd_non_transactional_update(const MYSQL_THD thd)
{
return(thd->transaction.all.modified_non_trans_table);
diff --git a/storage/innobase/lock/lock0lock.cc
b/storage/innobase/lock/lock0lock.cc
index b1cf2152cd6..469d03eaa06 100644
--- a/storage/innobase/lock/lock0lock.cc
+++ b/storage/innobase/lock/lock0lock.cc
@@ -49,6 +49,8 @@ Created 5/7/1996 Heikki Tuuri
#include <mysql/service_wsrep.h>
#endif /* WITH_WSREP */
+extern "C" int thd_deadlock_victim_preference(const MYSQL_THD thd1, const
MYSQL_THD thd2);
+
/** Lock scheduling algorithm */
ulong innodb_lock_schedule_algorithm;
@@ -1538,6 +1540,16 @@ static bool has_higher_priority(lock_t *lock1, lock_t
*lock2)
} else if (!lock_get_wait(lock2)) {
return false;
}
+ // Ask the upper server layer if any of the two trx should be prefered.
+ int preference = thd_deadlock_victim_preference(lock1->trx->mysql_thd,
+ lock2->trx->mysql_thd);
+ if (preference == -1) {
+ // lock1 is preferred as a victim, so lock2 has higher priority
+ return false;
+ } else if (preference == 1) {
+ // lock2 is preferred as a victim, so lock1 has higher priority
+ return true;
+ }
return lock1->trx->start_time_micro <= lock2->trx->start_time_micro;
}
diff --git a/storage/innobase/trx/trx0trx.cc b/storage/innobase/trx/trx0trx.cc
index 7cd95878b0c..0771d764fb6 100644
--- a/storage/innobase/trx/trx0trx.cc
+++ b/storage/innobase/trx/trx0trx.cc
@@ -52,6 +52,9 @@ Created 3/26/1996 Heikki Tuuri
#include <set>
#include <new>
+extern "C"
+int thd_deadlock_victim_preference(const MYSQL_THD thd1, const MYSQL_THD thd2);
+
/** The bit pattern corresponding to TRX_ID_MAX */
const byte trx_id_max_bytes[8] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
@@ -1906,6 +1909,15 @@ trx_weight_ge(
{
ibool a_notrans_edit;
ibool b_notrans_edit;
+ int pref;
+
+ /* First ask the upper server layer if it has any preference for which
+ to prefer as a deadlock victim. */
+ pref= thd_deadlock_victim_preference(a->mysql_thd, b->mysql_thd);
+ if (pref < 0)
+ return FALSE;
+ else if (pref > 0)
+ return TRUE;
/* If mysql_thd is NULL for a transaction we assume that it has
not edited non-transactional tables. */
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