mariadb/mysql-test/r/lock_multi.result
davi@mysql.com/endora.local 137e90ed55 Bug#32395 Alter table under a impending global read lock causes a server crash
The problem is that some DDL statements (ALTER TABLE, CREATE
TRIGGER, FLUSH TABLES, ...) when under LOCK TABLES need to
momentarily drop the lock, reopen the table and grab the write
lock again (using reopen_tables). When grabbing the lock again,
reopen_tables doesn't pass a flag to mysql_lock_tables in
order to ignore the impending global read lock, which causes a
assertion because LOCK_open is being hold. Also dropping the
lock must not signal to any threads that the table has been
relinquished (related to the locking/flushing protocol).

The solution is to correct the way the table is reopenned
and the locks grabbed. When reopening the table and under
LOCK TABLES, the table version should be set to 0 so other
threads have to wait for the table. When grabbing the lock,
any other flush should be ignored because it's theoretically
a atomic operation. The chosen solution also fixes a potential
discrepancy between binlog and GRL (global read lock) because
table placeholders were being ignored, now a FLUSH TABLES WITH
READ LOCK will properly for table with open placeholders.

It's also important to mention that this patch doesn't fix
a potential deadlock if one uses two GRLs under LOCK TABLES
concurrently.
2007-12-12 19:44:14 -02:00

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drop table if exists t1,t2;
create table t1(n int);
insert into t1 values (1);
lock tables t1 write;
update low_priority t1 set n = 4;
select n from t1;
unlock tables;
n
4
drop table t1;
create table t1(n int);
insert into t1 values (1);
lock tables t1 read;
update low_priority t1 set n = 4;
select n from t1;
n
1
unlock tables;
drop table t1;
create table t1 (a int, b int);
create table t2 (c int, d int);
insert into t1 values(1,1);
insert into t1 values(2,2);
insert into t2 values(1,2);
lock table t1 read;
update t1,t2 set c=a where b=d;
select c from t2;
c
2
drop table t1;
drop table t2;
create table t1 (a int);
create table t2 (a int);
lock table t1 write, t2 write;
insert t1 select * from t2;
drop table t2;
ERROR 42S02: Table 'test.t2' doesn't exist
drop table t1;
create table t1 (a int);
create table t2 (a int);
lock table t1 write, t2 write, t1 as t1_2 write, t2 as t2_2 write;
insert t1 select * from t2;
drop table t2;
ERROR 42S02: Table 'test.t2' doesn't exist
drop table t1;
End of 4.1 tests
create table t1(a int);
lock tables t1 write;
show columns from t1;
Field Type Null Key Default Extra
a int(11) YES NULL
unlock tables;
drop table t1;
use mysql;
LOCK TABLES columns_priv WRITE, db WRITE, host WRITE, user WRITE;
FLUSH TABLES;
use mysql;
SELECT user.Select_priv FROM user, db WHERE user.user = db.user LIMIT 1;
OPTIMIZE TABLES columns_priv, db, host, user;
Table Op Msg_type Msg_text
mysql.columns_priv optimize status OK
mysql.db optimize status OK
mysql.host optimize status OK
mysql.user optimize status OK
UNLOCK TABLES;
Select_priv
N
use test;
use test;
CREATE TABLE t1 (c1 int);
LOCK TABLE t1 WRITE;
FLUSH TABLES WITH READ LOCK;
CREATE TABLE t2 (c1 int);
UNLOCK TABLES;
UNLOCK TABLES;
DROP TABLE t1, t2;
CREATE TABLE t1 (c1 int);
LOCK TABLE t1 WRITE;
FLUSH TABLES WITH READ LOCK;
CREATE TABLE t2 AS SELECT * FROM t1;
ERROR HY000: Table 't2' was not locked with LOCK TABLES
UNLOCK TABLES;
UNLOCK TABLES;
DROP TABLE t1;
CREATE DATABASE mysqltest_1;
FLUSH TABLES WITH READ LOCK;
DROP DATABASE mysqltest_1;
DROP DATABASE mysqltest_1;
ERROR HY000: Can't execute the query because you have a conflicting read lock
UNLOCK TABLES;
DROP DATABASE mysqltest_1;
ERROR HY000: Can't drop database 'mysqltest_1'; database doesn't exist
create table t1 (f1 int(12) unsigned not null auto_increment, primary key(f1)) engine=innodb;
lock tables t1 write;
alter table t1 auto_increment=0;
alter table t1 auto_increment=0;
unlock tables;
drop table t1;
End of 5.0 tests
create table t1 (i int);
lock table t1 read;
update t1 set i= 10;;
select * from t1;;
kill query ID;
i
ERROR 70100: Query execution was interrupted
unlock tables;
drop table t1;
drop table if exists t1;
create table t1 (a int) ENGINE=MEMORY;
--> client 2
handler t1 open;
ERROR HY000: Table storage engine for 't1' doesn't have this option
--> client 1
drop table t1;
drop table if exists t1;
create table t1 (i int);
connection: default
lock tables t1 write;
connection: flush
flush tables with read lock;;
connection: default
alter table t1 add column j int;
connection: insert
insert into t1 values (1,2);;
connection: default
unlock tables;
connection: flush
select * from t1;
i j
unlock tables;
select * from t1;
i j
1 2
drop table t1;
drop table if exists t1;
create table t1 (i int);
connection: default
lock tables t1 write;
connection: flush
flush tables with read lock;;
connection: default
flush tables;
unlock tables;
drop table t1;
End of 5.1 tests