#
# Bug #18451287 REDUNDANT DELETE MARKING AFTER DB_LOCK_WAIT
#
create table t1 (f1 int primary key, f2 blob) engine=innodb;
create table t2 (f1 int primary key, f2 int,
foreign key (f2) references t1(f1) on update cascade) engine=innodb;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`f1` int(11) NOT NULL,
`f2` blob DEFAULT NULL,
PRIMARY KEY (`f1`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`f1` int(11) NOT NULL,
`f2` int(11) DEFAULT NULL,
PRIMARY KEY (`f1`),
KEY `f2` (`f2`),
CONSTRAINT `1` FOREIGN KEY (`f2`) REFERENCES `t1` (`f1`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
insert into t1 values (1, repeat('+', 20000));
insert into t1 values (2, repeat('-', 20000));
insert into t1 values (3, repeat('=', 20000));
insert into t2 values (1, 2);
select f1, right(f2, 20) as p2 from t1;
f1 p2 1 ++++++++++++++++++++ 2 -------------------- 3 ====================
select f1, f2 from t2;
f1 f2 12
connect con1,localhost,root,,test;
start transaction;
select f1, f2 from t2 for update;
f1 f2 12
connection default; set debug_sync='lock_wait_start SIGNAL upd_waiting WAIT_FOR go_upd';
update t1 set f1 = 10 where f1 = 2;
connection con1; set debug_sync='now WAIT_FOR upd_waiting';
rollback; set debug_sync='now SIGNAL go_upd';
connection default;
# reap: update t1 set f1 = 10 where f1 = 2;
select f1, right(f2, 20) as p2 from t1;
f1 p2 1 ++++++++++++++++++++ 3 ==================== 10 --------------------
select f1, f2 from t2;
f1 f2 110
drop table t2, t1; set debug_sync = reset;
#
# Test Scenario: Two tables t1 -> t2 are involved in update cascade.
# If DB_LOCK_WAIT happens when t1 is being updated and FK constraints
# are being checked in t2, then retry must happen on t1. The update
# cascade happens in secondary index. For secondary index testing,
# blobs are not needed.
#
create table t1 (f1 int primary key, f2 int, key k1(f2)) engine=innodb;
create table t2 (f1 int primary key, f2 int,
foreign key (f2) references t1(f2) on update cascade) engine=innodb;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`f1` int(11) NOT NULL,
`f2` int(11) DEFAULT NULL,
PRIMARY KEY (`f1`),
KEY `k1` (`f2`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`f1` int(11) NOT NULL,
`f2` int(11) DEFAULT NULL,
PRIMARY KEY (`f1`),
KEY `f2` (`f2`),
CONSTRAINT `1` FOREIGN KEY (`f2`) REFERENCES `t1` (`f2`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
insert into t1 values (1, 91);
insert into t2 values (1, 91);
select f1, f2 from t1;
f1 f2 191
select f1, f2 from t2;
f1 f2 191
connection con1;
start transaction;
select f1, f2 from t2 for update;
f1 f2 191
connection default; set debug_sync='lock_wait_start SIGNAL upd_waiting WAIT_FOR go_upd';
update t1 set f2 = 28 where f2 = 91;
connection con1; set debug_sync='now WAIT_FOR upd_waiting';
rollback; set debug_sync='now SIGNAL go_upd';
connection default;
# reap: update t1 set f1 = 10 where f1 = 2;
select f1, f2 from t1;
f1 f2 128
select f1, f2 from t2;
f1 f2 128
drop table t2, t1; set debug_sync = reset;
#
# Test Scenario: Three tables t1 -> t2 -> t3 are involved in update cascade.
# If DB_LOCK_WAIT happens when t2 is being updated, then retry must happen
# on t2.
#
create table t1 (f1 int primary key, f2 blob) engine=innodb;
create table t2 (f1 int primary key, f2 blob,
foreign key (f1) references t1(f1) on update cascade) engine=innodb;
create table t3 (f1 int primary key, f2 blob,
foreign key (f1) references t2(f1) on update cascade) engine=innodb;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`f1` int(11) NOT NULL,
`f2` blob DEFAULT NULL,
PRIMARY KEY (`f1`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`f1` int(11) NOT NULL,
`f2` blob DEFAULT NULL,
PRIMARY KEY (`f1`),
CONSTRAINT `1` FOREIGN KEY (`f1`) REFERENCES `t1` (`f1`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t3;
Table Create Table
t3 CREATE TABLE `t3` (
`f1` int(11) NOT NULL,
`f2` blob DEFAULT NULL,
PRIMARY KEY (`f1`),
CONSTRAINT `1` FOREIGN KEY (`f1`) REFERENCES `t2` (`f1`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
insert into t1 values (2, repeat('-', 20000));
insert into t2 values (2, repeat('%', 20000));
insert into t3 values (2, repeat('+', 20000));
select f1, right(f2, 20) as p2 from t1;
f1 p2 2 --------------------
select f1, right(f2, 20) as p2 from t2;
f1 p2 2 %%%%%%%%%%%%%%%%%%%%
select f1, right(f2, 20) as p2 from t3;
f1 p2 2 ++++++++++++++++++++
connection con1;
start transaction;
select f1 from t3 for update;
f1 2
connection default; set debug_sync='lock_wait_start SIGNAL upd_waiting WAIT_FOR go_upd';
update t1 set f1 = 10 where f1 = 2;
connection con1; set debug_sync='now WAIT_FOR upd_waiting';
rollback;
# The table t1 is updated.
# In t2 delete-mark happened. Retry will happen on t2.
# In t3 yet to be updated. set session transaction isolation level read uncommitted;
start transaction;
select f1, right(f2, 20) as p2 from t1;
f1 p2
select f1, right(f2, 20) as p2 from t2;
f1 p2
select f1, right(f2, 20) as p2 from t3;
f1 p2 2 ++++++++++++++++++++
commit; set debug_sync='now SIGNAL go_upd';
connection default;
# reap: update t1 set f1 = 10 where f1 = 2;
start transaction;
select f1, right(f2, 20) as p2 from t1;
f1 p2 10 --------------------
select f1, right(f2, 20) as p2 from t2;
f1 p2 10 %%%%%%%%%%%%%%%%%%%%
select f1, right(f2, 20) as p2 from t3;
f1 p2 10 ++++++++++++++++++++
commit;
drop table t3, t2, t1; set debug_sync = reset;
#
# Test Scenario: Three tables t1 -> t2 -> t3 are involved in update
# cascade. If DB_LOCK_WAIT happens when t2 is being updated, then
# retry must happen on t2. The update cascade is happening via
# secondary index (hence blobs are not needed).
#
create table t1 (f1 int primary key, f2 int, key k1(f2)) engine=innodb;
create table t2 (f1 int primary key, f2 int,
foreign key (f2) references t1(f2) on update cascade) engine=innodb;
create table t3 (f1 int primary key, f2 int,
foreign key (f2) references t2(f2) on update cascade) engine=innodb;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`f1` int(11) NOT NULL,
`f2` int(11) DEFAULT NULL,
PRIMARY KEY (`f1`),
KEY `k1` (`f2`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`f1` int(11) NOT NULL,
`f2` int(11) DEFAULT NULL,
PRIMARY KEY (`f1`),
KEY `f2` (`f2`),
CONSTRAINT `1` FOREIGN KEY (`f2`) REFERENCES `t1` (`f2`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t3;
Table Create Table
t3 CREATE TABLE `t3` (
`f1` int(11) NOT NULL,
`f2` int(11) DEFAULT NULL,
PRIMARY KEY (`f1`),
KEY `f2` (`f2`),
CONSTRAINT `1` FOREIGN KEY (`f2`) REFERENCES `t2` (`f2`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
insert into t1 values (2, 91);
insert into t2 values (2, 91);
insert into t3 values (2, 91);
select f1, f2 from t1;
f1 f2 291
select f1, f2 from t2;
f1 f2 291
select f1, f2 from t3;
f1 f2 291
connection con1;
start transaction;
select f1 from t3 for update;
f1 2
connection default; set debug_sync='lock_wait_start SIGNAL upd_waiting WAIT_FOR go_upd';
update t1 set f2 = 28 where f2 = 91;
connection con1; set debug_sync='now WAIT_FOR upd_waiting';
rollback;
# The table t1 is updated.
# In t2 delete-mark happened. Retry will happen on t2.
# In t3 yet to be updated. set session transaction isolation level read uncommitted;
start transaction;
select f1, f2 from t1;
f1 f2
select f1, f2 from t2;
f1 f2
select f1, f2 from t3;
f1 f2 291
commit; set debug_sync='now SIGNAL go_upd';
disconnect con1;
connection default;
# reap: update t1 set f2 = 28 where f2 = 91;
start transaction;
select f1, f2 from t1;
f1 f2 228
select f1, f2 from t2;
f1 f2 228
select f1, f2 from t3;
f1 f2 228
commit;
drop table t3, t2, t1; set debug_sync = reset;
Messung V0.5 in Prozent
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(vorverarbeitet am 2026-10-08)
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