mirror of
https://github.com/MariaDB/server.git
synced 2025-01-17 20:42:30 +01:00
cd8054d431
in a deadlock-free manner. This splits locking the global read lock in two steps. This fixes a consequence of this bug, known as: BUG#4953 'mysqldump --master-data may report incorrect binlog position if using InnoDB' And a test. sql/handler.cc: making COMMIT wait if FLUSH TABLES WITH READ LOCK happened. sql/lock.cc: an additional stage so that FLUSH TABLES WITH READ LOCK blocks COMMIT: make_global_read_lock_block_commit(): taking the global read lock is TWO steps (2nd step is optional; without it, COMMIT of existing transactions will be allowed): lock_global_read_lock() THEN make_global_read_lock_block_commit(). sql/mysql_priv.h: new argument to wait_if_global_read_lock() sql/sql_class.h: THD::global_read_lock now an uint to reflect the 2 steps of global read lock (does not block COMMIT / does) sql/sql_db.cc: update for new prototype sql/sql_parse.cc: implementing the two steps of global read lock so that FLUSH TABLES WITH READ LOCK can block COMMIT without deadlocking with COMMITs.
49 lines
1,019 B
Text
49 lines
1,019 B
Text
# Let's see if FLUSH TABLES WITH READ LOCK blocks COMMIT of existing
|
|
# transactions.
|
|
# We verify that we did not introduce a deadlock.
|
|
|
|
-- source include/have_innodb.inc
|
|
|
|
connect (con1,localhost,root,,);
|
|
connect (con2,localhost,root,,);
|
|
connect (con3,localhost,root,,);
|
|
connection con1;
|
|
drop table if exists t1;
|
|
create table t1 (a int) type=innodb;
|
|
|
|
# blocks COMMIT ?
|
|
|
|
begin;
|
|
insert into t1 values(1);
|
|
connection con2;
|
|
flush tables with read lock;
|
|
select * from t1;
|
|
connection con1;
|
|
send commit; # blocked by con2
|
|
sleep 1;
|
|
connection con2;
|
|
select * from t1; # verify con1 was blocked and data did not move
|
|
unlock tables;
|
|
connection con1;
|
|
reap;
|
|
|
|
# No deadlock ?
|
|
|
|
connection con1;
|
|
begin;
|
|
select * from t1 for update;
|
|
connection con2;
|
|
begin;
|
|
send select * from t1 for update; # blocked by con1
|
|
sleep 1;
|
|
connection con3;
|
|
send flush tables with read lock; # blocked by con2
|
|
connection con1;
|
|
commit; # should not be blocked by con3
|
|
connection con2;
|
|
reap;
|
|
connection con3;
|
|
reap;
|
|
unlock tables;
|
|
connection con1;
|
|
drop table t1;
|