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c7e7a7d20c
and MDL". Concurrent execution of a multi-DELETE statement and ALTER TABLE statement which affected one of the tables used in the multi-DELETE sometimes led to deadlock. Similar deadlocks might have occured when one performed INSERT/UPDATE/DELETE on a view and concurrently executed ALTER TABLE for the view's underlying table, or when one concurrently executed TRUNCATE TABLE for InnoDB table and ALTER TABLE for the same table. These deadlocks were caused by a discrepancy between types of metadata and thr_lock.cc locks acquired by those statements. What happened was that multi-DELETE/TRUNCATE/DML-through-the- view statement in the first connection acquired SR lock on a table, then ALTER TABLE would come in in the second connection and acquire SNW metadata lock and TL_WRITE_ALLOW_READ thr_lock.c lock and then would start waiting for the first connection during lock upgrade. After that the statement in the first connection would try to acquire TL_WRITE lock on table and would start waiting for the second connection, creating a deadlock. This patch solves this problem by ensuring that we acquire SW metadata lock in all cases in which we acquiring write thr_lock.c lock. This guarantees that deadlocks like the one described above won't occur since all lock conflicts in such situation are resolved within MDL subsystem. This patch also adds assert which should guarantee that such situations won't arise in future.
350 lines
8.4 KiB
Text
350 lines
8.4 KiB
Text
drop table if exists t1,t2;
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create table t1(n int);
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insert into t1 values (1);
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select get_lock("mysqltest_lock", 100);
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get_lock("mysqltest_lock", 100)
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1
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update t1 set n = 2 and get_lock('mysqltest_lock', 100);
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update low_priority t1 set n = 4;
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select n from t1;
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select release_lock("mysqltest_lock");
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release_lock("mysqltest_lock")
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1
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select release_lock("mysqltest_lock");
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release_lock("mysqltest_lock")
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1
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n
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4
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drop table t1;
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create table t1(n int);
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insert into t1 values (1);
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select get_lock("mysqltest_lock", 100);
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get_lock("mysqltest_lock", 100)
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1
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select n from t1 where get_lock('mysqltest_lock', 100);
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update low_priority t1 set n = 4;
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select n from t1;
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n
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1
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select release_lock("mysqltest_lock");
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release_lock("mysqltest_lock")
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1
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n
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1
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select release_lock("mysqltest_lock");
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release_lock("mysqltest_lock")
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1
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drop table t1;
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create table t1 (a int, b int);
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create table t2 (c int, d int);
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insert into t1 values(1,1);
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insert into t1 values(2,2);
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insert into t2 values(1,2);
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lock table t1 read;
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update t1,t2 set c=a where b=d;
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select c from t2;
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c
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2
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unlock tables;
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drop table t1;
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drop table t2;
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create table t1 (a int);
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create table t2 (a int);
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lock table t1 write, t2 write;
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insert t1 select * from t2;
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drop table t2;
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unlock tables;
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ERROR 42S02: Table 'test.t2' doesn't exist
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drop table t1;
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create table t1 (a int);
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create table t2 (a int);
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lock table t1 write, t2 write, t1 as t1_2 write, t2 as t2_2 write;
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insert t1 select * from t2;
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drop table t2;
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unlock tables;
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ERROR 42S02: Table 'test.t2' doesn't exist
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drop table t1;
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End of 4.1 tests
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create table t1(a int);
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lock tables t1 write;
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show columns from t1;
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Field Type Null Key Default Extra
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a int(11) YES NULL
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unlock tables;
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drop table t1;
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USE mysql;
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LOCK TABLES columns_priv WRITE, db WRITE, host WRITE, user WRITE;
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FLUSH TABLES;
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USE mysql;
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SELECT user.Select_priv FROM user, db WHERE user.user = db.user LIMIT 1;
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OPTIMIZE TABLES columns_priv, db, host, user;
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Table Op Msg_type Msg_text
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mysql.columns_priv optimize status OK
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mysql.db optimize status OK
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mysql.host optimize status OK
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mysql.user optimize status OK
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UNLOCK TABLES;
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Select_priv
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N
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USE test;
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use test;
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CREATE TABLE t1 (c1 int);
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LOCK TABLE t1 WRITE;
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FLUSH TABLES WITH READ LOCK;
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CREATE TABLE t2 (c1 int);
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ERROR HY000: Table 't2' was not locked with LOCK TABLES
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UNLOCK TABLES;
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UNLOCK TABLES;
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DROP TABLE t1;
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CREATE TABLE t1 (c1 int);
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LOCK TABLE t1 WRITE;
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FLUSH TABLES WITH READ LOCK;
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CREATE TABLE t2 AS SELECT * FROM t1;
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ERROR HY000: Table 't2' was not locked with LOCK TABLES
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UNLOCK TABLES;
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UNLOCK TABLES;
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DROP TABLE t1;
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CREATE DATABASE mysqltest_1;
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FLUSH TABLES WITH READ LOCK;
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DROP DATABASE mysqltest_1;
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DROP DATABASE mysqltest_1;
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ERROR HY000: Can't execute the query because you have a conflicting read lock
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UNLOCK TABLES;
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DROP DATABASE mysqltest_1;
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ERROR HY000: Can't drop database 'mysqltest_1'; database doesn't exist
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create table t1 (f1 int(12) unsigned not null auto_increment, primary key(f1)) engine=innodb;
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lock tables t1 write;
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alter table t1 auto_increment=0;
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alter table t1 auto_increment=0;
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unlock tables;
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drop table t1;
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create table t1 (a int);
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create table t2 like t1;
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# con1
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lock tables t1 write;
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# con2
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flush tables with read lock;
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# con5
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# global read lock is taken
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# con3
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select * from t2 for update;
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# waiting for release of read lock
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# con4
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# would hang and later cause a deadlock
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flush tables t2;
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# clean up
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unlock tables;
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unlock tables;
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a
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drop table t1,t2;
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#
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# Lightweight version:
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# Ensure that the wait for a GRL is done before opening tables.
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#
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create table t1 (a int);
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create table t2 like t1;
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#
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# UPDATE
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#
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# default
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flush tables with read lock;
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# con1
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update t2 set a = 1;
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# default
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# statement is waiting for release of read lock
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# con2
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flush table t2;
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# default
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unlock tables;
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# con1
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#
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# LOCK TABLES .. WRITE
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#
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# default
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flush tables with read lock;
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# con1
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lock tables t2 write;
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# default
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# statement is waiting for release of read lock
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# con2
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flush table t2;
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# default
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unlock tables;
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# con1
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unlock tables;
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drop table t1,t2;
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End of 5.0 tests
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create table t1 (i int);
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lock table t1 read;
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update t1 set i= 10;
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select * from t1;
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kill query ID;
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i
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ERROR 70100: Query execution was interrupted
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unlock tables;
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drop table t1;
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drop table if exists t1;
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create table t1 (a int) ENGINE=MEMORY;
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--> client 2
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handler t1 open;
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ERROR HY000: Table storage engine for 't1' doesn't have this option
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--> client 1
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drop table t1;
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drop table if exists t1;
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create table t1 (i int);
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connection: default
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lock tables t1 write;
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connection: flush
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flush tables with read lock;;
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connection: default
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alter table t1 add column j int;
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connection: insert
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insert into t1 values (1,2);;
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connection: default
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unlock tables;
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connection: flush
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select * from t1;
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i j
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unlock tables;
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select * from t1;
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i j
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1 2
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drop table t1;
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drop table if exists t1;
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create table t1 (i int);
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connection: default
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lock tables t1 write;
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connection: flush
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flush tables with read lock;;
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connection: default
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flush tables;
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unlock tables;
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drop table t1;
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drop table if exists t1,t2;
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create table t1 (a int);
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flush status;
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lock tables t1 read;
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insert into t1 values(1);
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unlock tables;
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drop table t1;
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select @tlwa < @tlwb;
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@tlwa < @tlwb
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1
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End of 5.1 tests
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drop table if exists t1;
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create table t1 (i int);
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connection: default
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lock tables t1 write;
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connection: flush
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flush tables with read lock;;
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connection: default
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flush tables;
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drop table t1;
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#
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# Test for bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock".
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#
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drop table if exists t1;
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create table t1 (c1 int primary key, c2 int, c3 int);
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insert into t1 values (1,1,0),(2,2,0),(3,3,0),(4,4,0),(5,5,0);
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begin;
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update t1 set c3=c3+1 where c2=3;
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#
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# Switching to connection 'con46272'.
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# The below ALTER TABLE statement should wait till transaction
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# in connection 'default' is complete and then succeed.
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# It should not deadlock or fail with ER_LOCK_DEADLOCK error.
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# Sending:
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alter table t1 add column c4 int;;
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#
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# Switching to connection 'default'.
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# Wait until the above ALTER TABLE gets blocked because this
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# connection holds SW metadata lock on table to be altered.
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# The below statement should succeed. It should not
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# deadlock or end with ER_LOCK_DEADLOCK error.
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update t1 set c3=c3+1 where c2=4;
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# Unblock ALTER TABLE by committing transaction.
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commit;
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#
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# Switching to connection 'con46272'.
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# Reaping ALTER TABLE.
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#
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# Switching to connection 'default'.
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drop table t1;
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#
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# Bug#47249 assert in MDL_global_lock::is_lock_type_compatible
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#
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DROP TABLE IF EXISTS t1;
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DROP VIEW IF EXISTS v1;
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#
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# Test 1: LOCK TABLES v1 WRITE, t1 READ;
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#
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# Thanks to the fact that we no longer allow DDL on tables
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# which are locked for write implicitly, the exact scenario
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# in which assert was failing is no longer repeatable.
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CREATE TABLE t1 ( f1 integer );
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CREATE VIEW v1 AS SELECT f1 FROM t1 ;
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LOCK TABLES v1 WRITE, t1 READ;
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FLUSH TABLE t1;
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ERROR HY000: Table 't1' was locked with a READ lock and can't be updated
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UNLOCK TABLES;
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DROP TABLE t1;
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DROP VIEW v1;
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#
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# Test 2: LOCK TABLES t1 WRITE, v1 READ;
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#
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CREATE TABLE t1 ( f1 integer );
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CREATE VIEW v1 AS SELECT f1 FROM t1 ;
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# Connection 2
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LOCK TABLES t1 WRITE, v1 READ;
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FLUSH TABLE t1;
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# Connection 1
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LOCK TABLES t1 WRITE;
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FLUSH TABLE t1;
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DROP TABLE t1;
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DROP VIEW v1;
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#
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# Test for bug #50913 "Deadlock between open_and_lock_tables_derived
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# and MDL". Also see additional coverage in mdl_sync.test.
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#
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drop table if exists t1;
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drop view if exists v1;
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create table t1 (i int);
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create view v1 as select i from t1;
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begin;
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select * from t1;
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i
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# Switching to connection 'con50913'.
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# Sending:
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alter table t1 add column j int;
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# Switching to connection 'default'.
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# Wait until ALTER TABLE gets blocked.
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# The below statement should try to acquire SW lock on 't1'
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# and therefore should get ER_LOCK_DEADLOCK error. Before
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# bug fix it acquired SR lock and hung on thr_lock.c lock.
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delete a from t1 as a where i = 1;
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ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
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# Unblock ALTER TABLE.
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commit;
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# Switching to connection 'con50913'.
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# Reaping ALTER TABLE;
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# Switching to connection 'default'.
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begin;
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select * from v1;
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i
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# Switching to connection 'con50913'.
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# Sending:
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alter table t1 drop column j;
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# Switching to connection 'default'.
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# Wait until ALTER TABLE gets blocked.
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# The below statement should try to acquire SW lock on 't1'
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# and therefore should get ER_LOCK_DEADLOCK error. Before
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# bug fix it acquired SR lock and hung on thr_lock.c lock.
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insert into v1 values (1);
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ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
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# Unblock ALTER TABLE.
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commit;
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# Switching to connection 'con50913'.
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# Reaping ALTER TABLE;
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# Switching to connection 'default'.
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drop view v1;
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drop table t1;
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