SET DEBUG_SYNC= 'RESET';
drop table if exists t1,t2,t3;
create table t1 (i int);
create table t2 (i int);
connection: default
lock tables t2 read;
connection: con1
set debug_sync='mdl_upgrade_lock SIGNAL parked WAIT_FOR go';
alter table t1 rename t3;
connection: default
set debug_sync= 'now WAIT_FOR parked';
connection: con2
set debug_sync='mdl_acquire_lock_wait SIGNAL go';
drop table t1,t2;
connection: con1
connection: default
unlock tables;
connection: con2
ERROR 42S02: Unknown table 'test.t1'
drop table t3;
SET DEBUG_SYNC= 'RESET';
#
# Basic test coverage for type-of-operation aware metadata locks.
#
drop table if exists t1, t2, t3;
set debug_sync= 'RESET';
create table t1 (c1 int);
# 
# A) First let us check compatibility rules between differend kinds of
#    type-of-operation aware metadata locks.
#    Of course, these rules are already covered by the tests scattered
#    across the test suite. But it still makes sense to have one place
#    which covers all of them.
#
# 1) Acquire S (simple shared) lock on the table (by using HANDLER):
#
handler t1 open;
# 
# Switching to connection 'mdl_con1'.
# Check that S, SH, SR and SW locks are compatible with it.
handler t1 open t;
handler t close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
select count(*) from t1;
count(*)
0
insert into t1 values (1), (1);
# Check that SU lock is compatible with it. To do this use ALTER TABLE
# which will fail when constructing .frm and thus obtaining SU metadata
# lock.
alter table t1 add index (not_exist);
ERROR 42000: Key column 'not_exist' doesn't exist in table
# Check that SNW lock is compatible with it. To do this use ALTER TABLE
# which will fail during copying the table and thus obtaining SNW metadata
# lock.
alter table t1 add primary key (c1);
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# Check that SNRW lock is compatible with S lock.
lock table t1 write;
insert into t1 values (1);
unlock tables;
# Check that X lock is incompatible with S lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above RENAME is blocked because of S lock.
# 
# Switching to connection 'default'.
# Unblock RENAME TABLE.
handler t1 close;
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME TABLE.
# Restore the original state of the things.
rename table t2 to t1;
# 
# Switching to connection 'default'.
handler t1 open;
# 
# Switching to connection 'mdl_con1'.
# Check that upgrade from SNW to X is blocked by presence of S lock.
# Sending:
alter table t1 add column c2 int;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above ALTER TABLE is blocked because of S lock.
# 
# Switching to connection 'default'.
# Unblock ALTER TABLE.
handler t1 close;
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
# Restore the original state of the things.
alter table t1 drop column c2;
# 
# Switching to connection 'default'.
handler t1 open;
# 
# Switching to connection 'mdl_con1'.
# Check that upgrade from SNRW to X is blocked by presence of S lock.
lock table t1 write;
# Sending:
alter table t1 add column c2 int;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above upgrade of SNRW to X in ALTER TABLE is blocked
# because of S lock.
# 
# Switching to connection 'default'.
# Unblock ALTER TABLE.
handler t1 close;
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
# Restore the original state of the things.
alter table t1 drop column c2;
unlock tables;
# 
# Switching to connection 'default'.
#
# 2) Acquire SH (shared high-priority) lock on the table.
#    We have to involve DEBUG_SYNC facility for this as usually
#    such kind of locks are short-lived.
#
set debug_sync= 'after_open_table_mdl_shared SIGNAL locked WAIT_FOR finish';
# Sending:
select table_name, table_type, auto_increment, table_comment from information_schema.tables where table_schema='test' and table_name='t1';;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that S, SH, SR and SW locks are compatible with it.
handler t1 open;
handler t1 close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
select count(*) from t1;
count(*)
3
insert into t1 values (1);
# Check that SU lock is compatible with it. To do this use ALTER TABLE
# which will fail when constructing .frm and thus obtaining SU metadata
# lock.
alter table t1 add index (not_exist);
ERROR 42000: Key column 'not_exist' doesn't exist in table
# Check that SNW lock is compatible with it. To do this use ALTER TABLE
# which will fail during copying the table and thus obtaining SNW metadata
# lock.
alter table t1 add primary key (c1);
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# Check that SNRW lock is compatible with SH lock.
lock table t1 write;
delete from t1 limit 1;
unlock tables;
# Check that X lock is incompatible with SH lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above RENAME is blocked because of SH lock.
# Unblock RENAME TABLE.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping SELECT ... FROM I_S.
table_name	table_type	auto_increment	table_comment
t1	BASE TABLE	NULL	
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME TABLE.
# Restore the original state of the things.
rename table t2 to t1;
# 
# Switching to connection 'default'.
set debug_sync= 'after_open_table_mdl_shared SIGNAL locked WAIT_FOR finish';
# Sending:
select table_name, table_type, auto_increment, table_comment from information_schema.tables where table_schema='test' and table_name='t1';;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that upgrade from SNW to X is blocked by presence of SH lock.
# Sending:
alter table t1 add column c2 int;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above ALTER TABLE is blocked because of SH lock.
# Unblock RENAME TABLE.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping SELECT ... FROM I_S.
table_name	table_type	auto_increment	table_comment
t1	BASE TABLE	NULL	
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
# Restore the original state of the things.
alter table t1 drop column c2;
# 
# Switching to connection 'default'.
set debug_sync= 'after_open_table_mdl_shared SIGNAL locked WAIT_FOR finish';
select table_name, table_type, auto_increment, table_comment from information_schema.tables where table_schema='test' and table_name='t1';;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that upgrade from SNRW to X is blocked by presence of S lock.
lock table t1 write;
# Sending:
alter table t1 add column c2 int;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above upgrade of SNRW to X in ALTER TABLE is blocked
# because of S lock.
# Unblock RENAME TABLE.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping SELECT ... FROM I_S.
table_name	table_type	auto_increment	table_comment
t1	BASE TABLE	NULL	
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
# Restore the original state of the things.
alter table t1 drop column c2;
unlock tables;
# 
# Switching to connection 'default'.
#
#
# 3) Acquire SR lock on the table.
#
#
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Check that S, SH, SR and SW locks are compatible with it.
handler t1 open;
handler t1 close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
select count(*) from t1;
count(*)
3
insert into t1 values (1);
# Check that SU lock is compatible with it. To do this use ALTER TABLE
# which will fail when constructing .frm and thus obtaining SU metadata
# lock.
alter table t1 add index (not_exist);
ERROR 42000: Key column 'not_exist' doesn't exist in table
# Check that SNW lock is compatible with it. To do this use ALTER TABLE
# which will fail during copying the table and thus obtaining SNW metadata
# lock.
alter table t1 add primary key (c1);
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# Check that SNRW lock is not compatible with SR lock.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'default'.
# Check that the above LOCK TABLES is blocked because of SR lock.
# Unblock LOCK TABLES.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reaping LOCK TABLES.
delete from t1 limit 1;
unlock tables;
# 
# Switching to connection 'default'.
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Check that X lock is incompatible with SR lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above RENAME is blocked because of SR lock.
# 
# Switching to connection 'default'.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME TABLE.
# Restore the original state of the things.
rename table t2 to t1;
# 
# Switching to connection 'default'.
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Check that upgrade from SNW to X is blocked by presence of SR lock.
# Sending:
alter table t1 add column c2 int;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above ALTER TABLE is blocked because of SR lock.
# 
# Switching to connection 'default'.
# Unblock ALTER TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
# Restore the original state of the things.
alter table t1 drop column c2;
#
# There is no need to check that upgrade from SNRW to X is blocked
# by presence of SR lock because SNRW is incompatible with SR anyway.
# 
# 
# Switching to connection 'default'.
#
#
# 4) Acquire SW lock on the table.
#
#
begin;
insert into t1 values (1);
# 
# Switching to connection 'mdl_con1'.
# Check that S, SH, SR and SW locks are compatible with it.
handler t1 open;
handler t1 close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
# Disable result log to make test robust against
# effects of concurrent insert.
select * from t1;
insert into t1 values (1);
# Check that SU lock is compatible with it. To do this use ALTER TABLE
# which will fail when constructing .frm and thus obtaining SU metadata
# lock.
alter table t1 add index (not_exist);
ERROR 42000: Key column 'not_exist' doesn't exist in table
# Check that SNW lock is not compatible with SW lock.
# Again we use ALTER TABLE which fails during copying
# the table to avoid upgrade of SNW -> X.
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'default'.
# Check that the above ALTER TABLE is blocked because of SW lock.
# Unblock ALTER TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'default'.
begin;
insert into t1 values (1);
# 
# Switching to connection 'mdl_con1'.
# Check that SNRW lock is not compatible with SW lock.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'default'.
# Check that the above LOCK TABLES is blocked because of SW lock.
# Unblock LOCK TABLES.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reaping LOCK TABLES.
delete from t1 limit 2;
unlock tables;
# 
# Switching to connection 'default'.
begin;
insert into t1 values (1);
# 
# Switching to connection 'mdl_con1'.
# Check that X lock is incompatible with SW lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above RENAME is blocked because of SW lock.
# 
# Switching to connection 'default'.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME TABLE.
# Restore the original state of the things.
rename table t2 to t1;
#
# There is no need to check that upgrade from SNW/SNRW to X is
# blocked by presence of SW lock because SNW/SNRW is incompatible
# with SW anyway.
# 
# 
# Switching to connection 'default'.
#
#
# 5) Acquire SU lock on the table. We have to use DEBUG_SYNC for
#    this, to prevent SU from being immediately upgraded to X.
#
set debug_sync= 'alter_opened_table SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that S, SH, SR and SW locks are compatible with it.
handler t1 open;
handler t1 close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
select count(*) from t1;
count(*)
5
delete from t1 limit 1;
# Check that SU lock is incompatible with SU lock.
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above ALTER is blocked because of SU lock.
# Unblock ALTERs.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping first ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con1'.
# Reaping another ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'default'.
set debug_sync= 'alter_opened_table SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that SNRW lock is incompatible with SU lock.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above LOCK TABLES is blocked because of SU lock.
# Unblock ALTER and thus LOCK TABLES.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con1'.
# Reaping LOCK TABLES
insert into t1 values (1);
unlock tables;
# 
# Switching to connection 'default'.
set debug_sync= 'alter_opened_table SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that X lock is incompatible with SU lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above RENAME is blocked because of SU lock.
# Unblock ALTER and thus RENAME TABLE.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Now we have ALTER TABLE with SU->SNW and RENAME TABLE with pending
# X-lock. In this case ALTER TABLE should be chosen as victim.
# Reaping ALTER TABLE.
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME TABLE
# Revert back to original state of things.
rename table t2 to t1;
#
# There is no need to check that upgrade from SNW/SNRW to X is
# blocked by presence of another SU lock because SNW/SNRW is
# incompatible with SU anyway.
# 
# Switching to connection 'default'.
#
#
# 6) Acquire SNW lock on the table. We have to use DEBUG_SYNC for
#    this, to prevent SNW from being immediately upgraded to X.
#
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1), lock=shared, algorithm=copy;;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that S, SH and SR locks are compatible with it.
handler t1 open;
handler t1 close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
select count(*) from t1;
count(*)
5
# Check that SW lock is incompatible with SNW lock.
# Sending:
delete from t1 limit 2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above DELETE is blocked because of SNW lock.
# Unblock ALTER and thus DELETE.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con1'.
# Reaping DELETE.
# 
# Switching to connection 'default'.
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1), lock=shared, algorithm=copy;;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that SU lock is incompatible with SNW lock.
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above ALTER is blocked because of SNW lock.
# Unblock ALTERs.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping first ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con1'.
# Reaping another ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Note that we can't easily check SNW vs SNW locks since
# SNW is only used by ALTER TABLE after upgrading from SU
# and SU is also incompatible with SNW.
#
# Switching to connection 'default'.
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1), lock=shared, algorithm=copy;;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that SNRW lock is incompatible with SNW lock.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above LOCK TABLES is blocked because of SNW lock.
# Unblock ALTER and thus LOCK TABLES.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con1'.
# Reaping LOCK TABLES
insert into t1 values (1);
unlock tables;
# 
# Switching to connection 'default'.
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1), algorithm=copy, lock=shared;;
# 
# Switching to connection 'mdl_con1'.
set debug_sync= 'now WAIT_FOR locked';
# Check that X lock is incompatible with SNW lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above RENAME is blocked because of SNW lock.
# Unblock ALTER and thus RENAME TABLE.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'default'.
# Reaping ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME TABLE
# Revert back to original state of things.
rename table t2 to t1;
#
# There is no need to check that upgrade from SNW/SNRW to X is
# blocked by presence of another SNW lock because SNW/SNRW is
# incompatible with SNW anyway.
# 
# Switching to connection 'default'.
#
#
# 7) Acquire SNRW lock on the table. 
#
#
lock table t1 write;
# 
# Switching to connection 'mdl_con1'.
# Check that S and SH locks are compatible with it.
handler t1 open;
handler t1 close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
# Check that SR lock is incompatible with SNRW lock.
# Sending:
select count(*) from t1;;
# 
# Switching to connection 'default'.
# Check that the above SELECT is blocked because of SNRW lock.
# Unblock SELECT.
unlock tables;
# 
# Switching to connection 'mdl_con1'.
# Reaping SELECT.
count(*)
4
# 
# Switching to connection 'default'.
lock table t1 write;
# 
# Switching to connection 'mdl_con1'.
# Check that SW lock is incompatible with SNRW lock.
# Sending:
delete from t1 limit 1;;
# 
# Switching to connection 'default'.
# Check that the above DELETE is blocked because of SNRW lock.
# Unblock DELETE.
unlock tables;
# 
# Switching to connection 'mdl_con1'.
# Reaping DELETE.
# 
# Switching to connection 'default'.
lock table t1 write;
# 
# Switching to connection 'mdl_con1'.
# Check that SU lock is incompatible with SNRW lock.
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'default'.
# Check that the above ALTER is blocked because of SNRW lock.
# Unblock ALTER.
unlock tables;
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Note that we can't easily check SNW vs SNRW locks since
# SNW is only used by ALTER TABLE after upgrading from SU
# and SU is also incompatible with SNRW.
#
# Switching to connection 'default'.
lock table t1 write;
# 
# Switching to connection 'mdl_con1'.
# Check that SNRW lock is incompatible with SNRW lock.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'default'.
# Check that the above LOCK TABLES is blocked because of SNRW lock.
# Unblock waiting LOCK TABLES.
unlock tables;
# 
# Switching to connection 'mdl_con1'.
# Reaping LOCK TABLES
insert into t1 values (1);
unlock tables;
# 
# Switching to connection 'default'.
lock table t1 write;
# 
# Switching to connection 'mdl_con1'.
# Check that X lock is incompatible with SNRW lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'default'.
# Check that the above RENAME is blocked because of SNRW lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME TABLE
# Revert back to original state of things.
rename table t2 to t1;
#
# There is no need to check that upgrade from SNW/SNRW to X is
# blocked by presence of another SNRW lock because SNW/SNRW is
# incompatible with SNRW anyway.
# 
# Switching to connection 'default'.
#
#
# 8) Now do the same round of tests for X lock. We use additional
#    table to get long-lived lock of this type.
#
create table t2 (c1 int);
# 
# Switching to connection 'mdl_con2'.
# Take a lock on t2, so RENAME TABLE t1 TO t2 will get blocked
# after acquiring X lock on t1.
lock tables t2 read;
# 
# Switching to connection 'default'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME has acquired X lock on t1 and is waiting for t2.
# Check that S lock in incompatible with X lock.
# Sending:
handler t1 open;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above HANDLER statement is blocked because of X lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping HANDLER.
handler t1 close;
# 
# Switching to connection 'mdl_con2'.
# Prepare for blocking RENAME TABLE.
lock tables t2 read;
# 
# Switching to connection 'default'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME has acquired X lock on t1 and is waiting for t2.
# Check that SH lock in incompatible with X lock.
# Sending:
select column_name from information_schema.columns where table_schema='test' and table_name='t1';;
# 
# Switching to connection 'mdl_con2'.
# Check that the above SELECT ... FROM I_S ... statement is blocked
# because of X lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping SELECT ... FROM I_S.
column_name
c1
# 
# Switching to connection 'mdl_con2'.
# Prepare for blocking RENAME TABLE.
lock tables t2 read;
# 
# Switching to connection 'default'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME has acquired X lock on t1 and is waiting for t2.
# Check that SR lock in incompatible with X lock.
# Sending:
select count(*) from t1;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above SELECT statement is blocked
# because of X lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping SELECT.
count(*)
4
# 
# Switching to connection 'mdl_con2'.
# Prepare for blocking RENAME TABLE.
lock tables t2 read;
# 
# Switching to connection 'default'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME has acquired X lock on t1 and is waiting for t2.
# Check that SW lock in incompatible with X lock.
# Sending:
delete from t1 limit 1;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above DELETE statement is blocked
# because of X lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping DELETE.
# 
# Switching to connection 'mdl_con2'.
# Prepare for blocking RENAME TABLE.
lock tables t2 read;
# 
# Switching to connection 'default'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME has acquired X lock on t1 and is waiting for t2.
# Check that SU lock is incompatible with X lock.
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above ALTER statement is blocked
# because of X lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
#
# Note that we can't easily check SNW vs X locks since
# SNW is only used by ALTER TABLE after upgrading from SU
# and SU is also incompatible with X.
#
# Switching to connection 'mdl_con2'.
# Prepare for blocking RENAME TABLE.
lock tables t2 read;
# 
# Switching to connection 'default'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME has acquired X lock on t1 and is waiting for t2.
# Check that SNRW lock is incompatible with X lock.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above LOCK TABLE statement is blocked
# because of X lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping LOCK TABLE.
unlock tables;
# 
# Switching to connection 'mdl_con2'.
# Prepare for blocking RENAME TABLE.
lock tables t2 read;
# 
# Switching to connection 'default'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME has acquired X lock on t1 and is waiting for t2.
# Check that X lock is incompatible with X lock.
# Sending:
rename table t1 to t3;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above RENAME statement is blocked
# because of X lock.
# Unblock RENAME TABLE
unlock tables;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping RENAME.
rename table t3 to t1;
#
# B) Now let us test compatibility in cases when both locks
#    are pending. I.e. let us test rules for priorities between
#    different types of metadata locks.
#
#    Note: No tests for pending SU lock as this lock requires
#          even stronger active or pending lock.
#
# 
# Switching to connection 'mdl_con2'.
#
# 1) Check compatibility for pending SNW lock.
#
# Acquire SW lock in order to create pending SNW lock later.
begin;
insert into t1 values (1);
# 
# Switching to connection 'default'.
# Add pending SNW lock.
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con1'.
# Check that ALTER TABLE is waiting with pending SNW lock.
# Check that S, SH and SR locks are compatible with pending SNW
handler t1 open t;
handler t close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
select count(*) from t1;
count(*)
4
# Check that SW is incompatible with pending SNW
# Sending:
delete from t1 limit 1;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above DELETE is blocked because of pending SNW lock.
# Unblock ALTER TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping ALTER.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con1'.
# Reaping DELETE.
#
# We can't do similar check for SNW, SNRW and X locks because
# they will also be blocked by active SW lock.
#
# 
# Switching to connection 'mdl_con2'.
#
# 2) Check compatibility for pending SNRW lock.
#
# Acquire SR lock in order to create pending SNRW lock.
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'default'.
# Add pending SNRW lock.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'mdl_con1'.
# Check that LOCK TABLE is waiting with pending SNRW lock.
# Check that S and SH locks are compatible with pending SNRW
handler t1 open t;
handler t close;
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
# Check that SR is incompatible with pending SNRW
# Sending:
select count(*) from t1;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above SELECT is blocked because of pending SNRW lock.
# Unblock LOCK TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping LOCK TABLE.
unlock tables;
# 
# Switching to connection 'mdl_con1'.
# Reaping SELECT.
count(*)
3
# Restore pending SNRW lock.
# 
# Switching to connection 'mdl_con2'.
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'default'.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'mdl_con1'.
# Check that LOCK TABLE is waiting with pending SNRW lock.
# Check that SW is incompatible with pending SNRW
# Sending:
insert into t1 values (1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above INSERT is blocked because of pending SNRW lock.
# Unblock LOCK TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping LOCK TABLE.
unlock tables;
# 
# Switching to connection 'mdl_con1'.
# Reaping INSERT.
# Restore pending SNRW lock.
# 
# Switching to connection 'mdl_con2'.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'default'.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'mdl_con1'.
# Check that LOCK TABLE is waiting with pending SNRW lock.
# Check that SNW is compatible with pending SNRW
# So ALTER TABLE statements are not starved by LOCK TABLEs.
alter table t1 add primary key (c1);
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'mdl_con2'.
# Unblock LOCK TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping LOCK TABLE.
unlock tables;
#
# We can't do similar check for SNRW and X locks because
# they will also be blocked by active SR lock.
#
# 
# Switching to connection 'mdl_con2'.
#
# 3) Check compatibility for pending X lock.
#
# Acquire SR lock in order to create pending X lock.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'default'.
# Add pending X lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME TABLE is waiting with pending X lock.
# Check that SH locks are compatible with pending X
select column_name from information_schema.columns where
table_schema='test' and table_name='t1';
column_name
c1
# Check that S is incompatible with pending X
# Sending:
handler t1 open;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above HANDLER OPEN is blocked because of pending X lock.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping HANDLER t1 OPEN.
handler t1 close;
# Restore pending X lock.
# 
# Switching to connection 'mdl_con2'.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'default'.
# Add pending X lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME TABLE is waiting with pending X lock.
# Check that SR is incompatible with pending X
# Sending:
select count(*) from t1;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above SELECT is blocked because of pending X lock.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping SELECT.
count(*)
4
# Restore pending X lock.
# 
# Switching to connection 'mdl_con2'.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'default'.
# Add pending X lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME TABLE is waiting with pending X lock.
# Check that SW is incompatible with pending X
# Sending:
delete from t1 limit 1;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above DELETE is blocked because of pending X lock.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping DELETE.
# Restore pending X lock.
# 
# Switching to connection 'mdl_con2'.
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'default'.
# Add pending X lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME TABLE is waiting with pending X lock.
# Check that SNW is incompatible with pending X
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above ALTER TABLE is blocked because of pending X lock.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# Restore pending X lock.
# 
# Switching to connection 'mdl_con2'.
handler t1 open;
# 
# Switching to connection 'default'.
# Add pending X lock.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that RENAME TABLE is waiting with pending X lock.
# Check that SNRW is incompatible with pending X
# Sending:
lock table t1 write;;
# 
# Switching to connection 'mdl_con3'.
# Check that the above LOCK TABLES is blocked because of pending X lock.
# 
# Switching to connection 'mdl_con2'.
# Unblock RENAME TABLE.
handler t1 close;
# 
# Switching to connection 'default'.
# Reaping RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'mdl_con1'.
# Reaping LOCK TABLES.
unlock tables;
# 
# Switching to connection 'default'.
#
#
# C) Now let us test how type-of-operation locks are handled in
#    transactional context. Obviously we are mostly interested
#    in conflicting types of locks.
#
#    Note: No tests for active/pending SU lock since
#          ALTER TABLE is in its own transaction.
#
#
# 1) Let us check how various locks used within transactional
#    context interact with active/pending SNW lock.
#
#    We start with case when we are acquiring lock on the table
#    which was not used in the transaction before.
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Create an active SNW lock on t2.
# We have to use DEBUG_SYNC facility as otherwise SNW lock
# will be immediately released (or upgraded to X lock).
insert into t2 values (1), (1);
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t2 add primary key (c1), algorithm=copy, lock=shared;;
# 
# Switching to connection 'default'.
set debug_sync= 'now WAIT_FOR locked';
# SR lock should be acquired without any waiting.
select count(*) from t2;
count(*)
2
commit;
# Now let us check that we will wait in case of SW lock.
begin;
select count(*) from t1;
count(*)
3
# Sending:
insert into t2 values (1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above INSERT is blocked.
# Unblock ALTER TABLE and thus INSERT.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'mdl_con1'.
# Reap ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'default'.
# Reap INSERT.
commit;
#
# Now let us see what happens when we are acquiring lock on the table
# which is already used in transaction.
#
# *) First, case when transaction which has SR lock on the table also
#    locked in SNW mode acquires yet another SR lock and then tries
#    to acquire SW lock.
begin;
select count(*) from t1;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Create an active SNW lock on t1.
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL locked WAIT_FOR finish';
# Sending:
alter table t1 add primary key (c1), algorithm=copy, lock=shared;;
# 
# Switching to connection 'default'.
set debug_sync= 'now WAIT_FOR locked';
# We should still be able to get SR lock without waiting.
select count(*) from t1;
count(*)
3
# Since the above ALTER TABLE is not upgrading SNW lock to X by waiting
# for SW lock we won't create deadlock.
# So the below INSERT should not end-up with ER_LOCK_DEADLOCK error.
# Sending:
insert into t1 values (1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above INSERT is blocked.
# Unblock ALTER TABLE and thus INSERT.
set debug_sync= 'now SIGNAL finish';
# 
# Switching to connection 'mdl_con1'.
# Reap ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'default'.
# Reap INSERT.
commit;
#
# **) Now test in which transaction that has SW lock on the table
#     against which there is pending SNW lock acquires SR and SW
#     locks on this table.
#
begin;
insert into t1 values (1);
# 
# Switching to connection 'mdl_con1'.
# Create pending SNW lock on t1.
# Sending:
alter table t1 add primary key (c1);;
# 
# Switching to connection 'default'.
# Wait until ALTER TABLE starts waiting for SNW lock.
# We should still be able to get both SW and SR locks without waiting.
select count(*) from t1;
count(*)
5
delete from t1 limit 1;
# Unblock ALTER TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap ALTER TABLE.
ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
# 
# Switching to connection 'default'.
#
# 2) Now similar tests for active SNW lock which is being upgraded
#    to X lock.
#
#    Again we start with case when we are acquiring lock on the
#    table which was not used in the transaction before.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con2'.
# Start transaction which will prevent SNW -> X upgrade from
# completing immediately.
begin;
select count(*) from t2;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Create SNW lock pending upgrade to X on t2.
# Sending:
alter table t2 add column c2 int;;
# 
# Switching to connection 'default'.
# Wait until ALTER TABLE starts waiting X lock.
# Check that attempt to acquire SR lock on t2 causes waiting.
# Sending:
select count(*) from t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above SELECT is blocked.
# Unblock ALTER TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap ALTER TABLE.
# 
# Switching to connection 'default'.
# Reap SELECT.
count(*)
3
commit;
# Do similar check for SW lock.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con2'.
# Start transaction which will prevent SNW -> X upgrade from
# completing immediately.
begin;
select count(*) from t2;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Create SNW lock pending upgrade to X on t2.
# Sending:
alter table t2 drop column c2;;
# 
# Switching to connection 'default'.
# Wait until ALTER TABLE starts waiting X lock.
# Check that attempt to acquire SW lock on t2 causes waiting.
# Sending:
insert into t2 values (1);;
# 
# Switching to connection 'mdl_con2'.
# Check that the above INSERT is blocked.
# Unblock ALTER TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap ALTER TABLE.
# 
# Switching to connection 'default'.
# Reap INSERT.
commit;
#
# Test for the case in which we are acquiring lock on the table
# which is already used in transaction.
#
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con1'.
# Create SNW lock pending upgrade to X.
# Sending:
alter table t1 add column c2 int;;
# 
# Switching to connection 'default'.
# Wait until ALTER TABLE starts waiting X lock.
# Check that transaction is still able to acquire SR lock.
select count(*) from t1;
count(*)
4
# Waiting trying to acquire SW lock will cause deadlock and
# therefore should cause an error.
delete from t1 limit 1;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
# Unblock ALTER TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap ALTER TABLE.
# 
# Switching to connection 'default'.
#
# 3) Check how various locks used within transactional context
#    interact with active/pending SNRW lock.
# 
#    Once again we start with case when we are acquiring lock on
#    the table which was not used in the transaction before.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con1'.
lock table t2 write;
# 
# Switching to connection 'default'.
# Attempt to acquire SR should be blocked. It should
# not cause errors as it does not creates deadlock.
# Sending:
select count(*) from t2;;
# 
# Switching to connection 'mdl_con1'.
# Check that the above SELECT is blocked 
# Unblock SELECT.
unlock tables;
# 
# Switching to connection 'default'.
# Reap SELECT.
count(*)
4
commit;
# Repeat the same test for SW lock.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con1'.
lock table t2 write;
# 
# Switching to connection 'default'.
# Again attempt to acquire SW should be blocked and should
# not cause any errors.
# Sending:
delete from t2 limit 1;;
# 
# Switching to connection 'mdl_con1'.
# Check that the above DELETE is blocked 
# Unblock DELETE.
unlock tables;
# 
# Switching to connection 'default'.
# Reap DELETE.
commit;
#
# Now coverage for the case in which we are acquiring lock on
# the table which is already used in transaction and against
# which there is a pending SNRW lock request.
#
# *) Let us start with case when transaction has only a SR lock.
#
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con1'.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'default'.
# Wait until LOCK TABLE is blocked creating pending request for X lock.
# Check that another instance of SR lock is granted without waiting.
select count(*) from t1;
count(*)
4
# Attempt to wait for SW lock will lead to deadlock, thus
# the below statement should end with ER_LOCK_DEADLOCK error.
delete from t1 limit 1;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
# Unblock LOCK TABLES.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap LOCK TABLES.
unlock tables;
# 
# Switching to connection 'default'.
#
# **) Now case when transaction has a SW lock.
#
begin;
delete from t1 limit 1;
# 
# Switching to connection 'mdl_con1'.
# Sending:
lock table t1 write;;
# 
# Switching to connection 'default'.
# Wait until LOCK TABLE is blocked creating pending request for X lock.
# Check that both SR and SW locks are granted without waiting
# and errors.
select count(*) from t1;
count(*)
3
insert into t1 values (1, 1);
# Unblock LOCK TABLES.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap LOCK TABLES.
unlock tables;
# 
# Switching to connection 'default'.
#
# 4) Check how various locks used within transactional context
#    interact with active/pending X lock.
# 
#    As usual we start with case when we are acquiring lock on
#    the table which was not used in the transaction before.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con2'.
# Start transaction which will prevent X lock from going away
# immediately.
begin;
select count(*) from t2;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Create pending X lock on t2.
# Sending:
rename table t2 to t3;;
# 
# Switching to connection 'default'.
# Wait until RENAME TABLE starts waiting with pending X lock.
# Check that attempt to acquire SR lock on t2 causes waiting.
# Sending:
select count(*) from t2;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above SELECT is blocked.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap RENAME TABLE.
# 
# Switching to connection 'default'.
# Reap SELECT.
ERROR 42S02: Table 'test.t2' doesn't exist
commit;
rename table t3 to t2;
# The same test for SW lock.
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con2'.
# Start transaction which will prevent X lock from going away
# immediately.
begin;
select count(*) from t2;
count(*)
3
# 
# Switching to connection 'mdl_con1'.
# Create pending X lock on t2.
# Sending:
rename table t2 to t3;;
# 
# Switching to connection 'default'.
# Wait until RENAME TABLE starts waiting with pending X lock.
# Check that attempt to acquire SW lock on t2 causes waiting.
# Sending:
delete from t2 limit 1;;
# 
# Switching to connection 'mdl_con2'.
# Check that the above DELETE is blocked.
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap RENAME TABLE.
# 
# Switching to connection 'default'.
# Reap DELETE.
ERROR 42S02: Table 'test.t2' doesn't exist
commit;
rename table t3 to t2;
#
# Coverage for the case in which we are acquiring lock on
# the table which is already used in transaction and against
# which there is a pending X lock request.
#
# *) The first case is when transaction has only a SR lock.
#
begin;
select count(*) from t1;
count(*)
4
# 
# Switching to connection 'mdl_con1'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'default'.
# Wait until RENAME TABLE is blocked creating pending request for X lock.
# Check that another instance of SR lock is granted without waiting.
select count(*) from t1;
count(*)
4
# Attempt to wait for SW lock will lead to deadlock, thus
# the below statement should end with ER_LOCK_DEADLOCK error.
delete from t1 limit 1;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'default'.
#
# **) The second case is when transaction has a SW lock.
#
begin;
delete from t1 limit 1;
# 
# Switching to connection 'mdl_con1'.
# Sending:
rename table t1 to t2;;
# 
# Switching to connection 'default'.
# Wait until RENAME TABLE is blocked creating pending request for X lock.
# Check that both SR and SW locks are granted without waiting
# and errors.
select count(*) from t1;
count(*)
3
insert into t1 values (1, 1);
# Unblock RENAME TABLE.
commit;
# 
# Switching to connection 'mdl_con1'.
# Reap RENAME TABLE.
ERROR 42S01: Table 't2' already exists
# 
# Switching to connection 'default'.
# Clean-up.
set debug_sync= 'RESET';
drop table t1, t2;
#
# Additional coverage for some scenarios in which not quite
# correct use of S metadata locks by HANDLER statement might
# have caused deadlocks.
#
drop table if exists t1, t2;
create table t1 (i int);
create table t2 (j int);
insert into t1 values (1);
#
# First, check scenario in which we upgrade SNRW lock to X lock
# on a table while having HANDLER READ trying to acquire TL_READ
# on the same table.
#
handler t1 open;
# 
# Switching to connection 'handler_con1'.
lock table t1 write;
# Upgrade SNRW to X lock.
# Sending:
alter table t1 add column j int;;
# 
# Switching to connection 'handler_con2'.
# Wait until ALTER is blocked during upgrade.
# 
# Switching to connection 'default'.
# The below statement should not cause deadlock.
handler t1 read first;;
# 
# Switching to connection 'handler_con1'.
# Reap ALTER TABLE.
unlock tables;
# 
# Switching to connection 'default'.
# Reap HANDLER READ.
i	j
1	NULL
handler t1 close;
#
# Now, check scenario in which upgrade of SNRW lock to X lock
# can be blocked by HANDLER which is open in connection currently
# waiting to get table-lock owned by connection doing upgrade.
#
handler t1 open;
# 
# Switching to connection 'handler_con1'.
lock table t1 write, t2 read;
# 
# Switching to connection 'default'.
# Execute statement which will be blocked on table-level lock
# owned by connection 'handler_con1'.
# Sending:
insert into t2 values (1);;
# 
# Switching to connection 'handler_con1'.
# Wait until INSERT is blocked on table-level lock.
# Sending 'alter table t1 drop column j'. It should not cause
# deadlock.
alter table t1 drop column j;
# Switching to connection 'handler_con2'.
# Wait until ALTER is blocked during upgrade.
# 
# Switching to connection 'default'.
# Reap INSERT.
ERROR HY000: Wait on a lock was aborted due to a pending exclusive lock
handler t1 close;
#
# Switching to connection 'handler_con1'.
# Reaping 'alter table t1 drop column j'
unlock tables;
# Switching to connection 'default'.
# Then, check the scenario in which upgrade of SNRW lock to X
# lock is blocked by HANDLER which is open in connection currently
# waiting to get SW lock on the same table.
#
handler t1 open;
# 
# Switching to connection 'handler_con1'.
lock table t1 write;
# 
# Switching to connection 'default'.
# The below insert should be blocked because active SNRW lock on 't1'.
# Sending:
insert into t1 values (1);;
# 
# Switching to connection 'handler_con1'.
# Wait until INSERT is blocked because of SNRW lock.
# The below ALTER TABLE will be blocked because of presence of HANDLER.
# Sending:
alter table t1 add column j int;;
# 
# Switching to connection 'default'.
# INSERT should be chosen as victim for resolving deadlock.
# Reaping INSERT.
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
# Close HANDLER to unblock ALTER TABLE.
handler t1 close;
# 
# Switching to connection 'handler_con1'.
# Reaping ALTER TABLE.
unlock tables;
# 
# Switching to connection 'default'.
#
# Finally, test in which upgrade of SNRW lock to X lock is blocked
# by HANDLER which is open in connection currently waiting to get
# SR lock on the table on which lock is upgraded.
#
handler t1 open;
# 
# Switching to connection 'handler_con1'.
lock table t1 write, t2 write;
# 
# Switching to connection 'default'.
# The below insert should be blocked because active SNRW lock on 't1'.
# Sending:
insert into t2 values (1);;
# 
# Switching to connection 'handler_con1'.
# Wait until INSERT is blocked because of SNRW lock.
# The below ALTER TABLE will be blocked because of presence of HANDLER.
# Sending:
alter table t1 drop column j;;
# 
# Switching to connection 'default'.
# INSERT should be chosen as victim for resolving deadlock.
# Reaping INSERT.
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
# Close HANDLER to unblock ALTER TABLE.
handler t1 close;
# 
# Switching to connection 'handler_con1'.
# Reaping ALTER TABLE.
unlock tables;
# 
# Switching to connection 'default'.
# Clean-up.
drop tables t1, t2;
#
# Test coverage for basic deadlock detection in metadata
# locking subsystem.
#
drop tables if exists t0, t1, t2, t3, t4, t5;
set debug_sync= 'RESET';
create table t1 (i int);
create table t2 (j int);
create table t3 (k int);
create table t4 (k int);
#
# Test for the case in which no deadlock occurs.
#
#
# Switching to connection 'deadlock_con1'.
begin;
insert into t1 values (1);
#
# Switching to connection 'deadlock_con2'.
begin;
insert into t2 values (1);
#
# Switching to connection 'default'.
# Send:
rename table t2 to t0, t3 to t2, t0 to t3;;
#
# Switching to connection 'deadlock_con1'.
# Wait until the above RENAME TABLE is blocked because it has to wait
# for 'deadlock_con2' which holds shared metadata lock on 't2'.
# The below statement should wait for exclusive metadata lock
# on 't2' to go away and should not produce ER_LOCK_DEADLOCK
# as no deadlock is possible in this situation.
# Send:
select * from t2;;
#
# Switching to connection 'deadlock_con2'.
# Wait until the above SELECT * FROM t2 is starts waiting
# for an exclusive metadata lock to go away.
#
# Unblock RENAME TABLE by releasing shared metadata lock on t2.
commit;
#
# Switching to connection 'default'.
# Reap RENAME TABLE.
#
# Switching to connection 'deadlock_con1'.
# Reap SELECT.
k
#
# Switching to connection 'default'.
#
# Let us check that in the process of waiting for conflicting lock
# on table 't2' to go away transaction in connection 'deadlock_con1'
# has not released metadata lock on table 't1'.
# Send:
rename table t1 to t0, t3 to t1, t0 to t3;;
#
# Switching to connection 'deadlock_con1'.
# Wait until the above RENAME TABLE is blocked because it has to wait
# for 'deadlock_con1' which should still hold shared metadata lock on
# table 't1'.
# Commit transaction to unblock RENAME TABLE.
commit;
#
# Switching to connection 'default'.
# Reap RENAME TABLE.
#
# Test for case when deadlock occurs and should be detected immediately.
#
#
# Switching to connection 'deadlock_con1'.
begin;
insert into t2 values (2);
#
# Switching to connection 'default'.
# Send:
rename table t2 to t0, t1 to t2, t0 to t1;;
#
# Switching to connection 'deadlock_con1'.
# Wait until the above RENAME TABLE is blocked because it has to wait
# for 'deadlock_con1' which holds shared metadata lock on 't2'.
# 
# The below statement should not wait as doing so will cause deadlock.
# Instead it should fail and emit ER_LOCK_DEADLOCK statement and 
# transaction should be rolled back.
select * from t1;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
#
# Switching to connection 'default'.
# Reap RENAME TABLE.
#
# Test for the case in which deadlock also occurs but not immediately.
#
#
# Switching to connection 'deadlock_con1'.
begin;
insert into t2 values (1);
#
# Switching to connection 'default'.
lock table t1 write;
#
# Switching to connection 'deadlock_con1'.
# The below SELECT statement should wait for metadata lock
# on table 't1' and should not produce ER_LOCK_DEADLOCK
# immediately as no deadlock is possible at the moment.
select * from t1;;
#
# Switching to connection 'deadlock_con2'.
# Wait until the above SELECT * FROM t1 is starts waiting
# for an UNRW metadata lock to go away.
# Send RENAME TABLE statement that will deadlock with the
# SELECT statement and thus should abort the latter.
rename table t1 to t0, t2 to t1, t0 to t2;;
#
# Switching to connection 'default'.
# Wait till above RENAME TABLE is blocked while holding
# pending X lock on t1.
# Allow the above RENAME TABLE to acquire lock on t1 and
# create pending lock on t2 thus creating deadlock.
unlock tables;
#
# Switching to connection 'deadlock_con1'.
# Since the latest RENAME TABLE entered in deadlock with SELECT
# statement the latter should be aborted and emit ER_LOCK_DEADLOCK
# error and transaction should be rolled back.
# Reap SELECT * FROM t1.
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
#
# Switching to connection 'deadlock_con2'.
# Reap RENAME TABLE ... .
#
# Switching to connection 'default'.
drop tables t1, t2, t3, t4;
#
# Now, test case which shows that deadlock detection empiric
# also takes into account requests for metadata lock upgrade.
#
create table t1 (i int);
insert into t1 values (1);
# Avoid race which occurs when SELECT in 'deadlock_con1' connection
# accesses table before the above INSERT unlocks the table and thus
# its result becomes visible to other connections.
select * from t1;
i
1
#
# Switching to connection 'deadlock_con1'.
begin;
select * from t1;
i
1
#
# Switching to connection 'default'.
# Send:
alter table t1 add column j int, rename to t2;;
#
# Switching to connection 'deadlock_con1'.
# Wait until the above ALTER TABLE ... RENAME acquires exclusive
# metadata lock on 't2' and starts waiting for connection
# 'deadlock_con1' which holds shared lock on 't1'.
# The below statement should not wait as it will cause deadlock.
# An appropriate error should be reported instead and transaction
# should be rolled back.
select * from t2;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
#
# Switching to connection 'default'.
# Reap ALTER TABLE ... RENAME.
drop table t2;
#
# Test that in situation when MDL subsystem detects a deadlock
# but it turns out that it can be resolved by backing-off locks
# acquired by one of participating transactions (which is
# possible when one of transactions consists only of currently
# executed statement, e.g. in autocommit mode) no error is
# reported.
#
create table t1 (i int);
create table t2 (j int);
# Ensure that the below SELECT stops once it has acquired metadata
# lock on table 't2'.
set debug_sync= 'after_open_table_mdl_shared SIGNAL locked WAIT_FOR finish';
# Sending:
select * from t2, t1;
#
# Switching to connection 'deadlock_con1'.
# Wait till SELECT acquires MDL on 't2' and starts waiting for signal.
set debug_sync= 'now WAIT_FOR locked';
# Sending:
lock tables t1 write, t2 write;
#
# Switching to connection 'deadlock_con2'.
# Wait until LOCK TABLES acquires SNRW lock on 't1' and is blocked
# while trying to acquire SNRW lock on 't1'.
# Resume SELECT execution, this should eventually unblock LOCK TABLES.
set debug_sync= 'now SIGNAL finish';
#
# Switching to connection 'deadlock_con1'.
# Reaping LOCK TABLES.
unlock tables;
#
# Switching to connection 'default'.
# Reaping SELECT. It succeed and not report ER_LOCK_DEADLOCK error.
j	i
drop tables t1, t2;
#
# Test coverage for situation in which a race has happened
# during deadlock detection process which led to unwarranted
# ER_LOCK_DEADLOCK error.
#
create table t1 (i int);
# Ensure that ALTER waits once it has acquired SNW lock.
set debug_sync='alter_table_copy_after_lock_upgrade SIGNAL parked1 WAIT_FOR go1';
# Sending:
alter table t1 add column j int;
#
# Switching to connection 'deadlock_con1'.
# Wait till ALTER acquires SNW lock and stops.
set debug_sync='now WAIT_FOR parked1';
# Ensure that INSERT is paused once it detects that there is
# a conflicting metadata lock so it has to wait, but before
# deadlock detection is run.
set debug_sync='mdl_acquire_lock_wait SIGNAL parked2 WAIT_FOR go2';
# Sending:
insert into t1 values ();
#
# Switching to connection 'deadlock_con2'.
# Wait till INSERT is paused.
set debug_sync='now WAIT_FOR parked2';
# Resume ALTER execution. Eventually it will release its
# metadata lock and INSERT's request for SW lock will be
# satisified.
set debug_sync='now SIGNAL go1';
#
# Switching to connection 'default'.
# Reaping ALTER TABLE.
# Add a new request for SNW lock to waiting graph.
# Sending:
alter table t1 drop column j;
#
# Switching to connection 'deadlock_con2'.
# Wait until ALTER is blocked.
# Resume INSERT so it can start deadlock detection.
#
# At this point there is a discrepancy between the fact that INSERT's
# SW lock is already satisfied, but INSERT's connection is still
# marked as waiting for it. Looking for a loop in waiters graph
# without additional checks has detected a deadlock (INSERT waits
# for SW lock; which is not granted because of pending SNW lock from
# ALTER; which waits for active SW lock from INSERT). Since requests
# for SW and SNW locks have same weight ALTER was selected as a victim
# and ended with ER_LOCK_DEADLOCK error.
set debug_sync='now SIGNAL go2';
#
# Switching to connection 'deadlock_con1'.
# Reaping INSERT.
#
# Switching to connection 'default'.
# Reaping ALTER. It should succeed and not produce ER_LOCK_DEADLOCK.
drop table t1;
#
# Now, test for a situation in which deadlock involves waiting not
# only in MDL subsystem but also for TDC. Such deadlocks should be
# successfully detected. If possible, they should be resolved without
# resorting to ER_LOCK_DEADLOCK error.
#
create table t1(i int);
create table t2(j int);
#
# First, let us check how we handle a simple scenario involving
# waits in MDL and TDC.
#
set debug_sync= 'RESET';
# Switching to connection 'deadlock_con1'.
# Start a statement, which will acquire SR metadata lock on t1, open it
# and then stop, before trying to acquire SW lock on t2 and opening it.
set debug_sync='open_tables_after_open_and_process_table SIGNAL parked WAIT_FOR go';
# Sending:
select * from t1 where i in (select j from t2 for update);
# Switching to connection 'deadlock_con2'.
# Wait till the above SELECT stops.
set debug_sync='now WAIT_FOR parked';
# The below FLUSH TABLES WITH READ LOCK should acquire
# SNW locks on t1 and t2 and wait till SELECT closes t1.
# Sending:
flush tables t1, t2 with read lock;
# Switching to connection 'deadlock_con3'.
# Wait until FLUSH TABLES WITH t1, t2 READ LOCK starts waiting
# for SELECT to close t1.
# Resume SELECT, so it tries to acquire SW lock on t1 and blocks,
# creating a deadlock. This deadlock should be detected and resolved
# by backing-off SELECT. As a result FTWRL should be able to finish.
set debug_sync='now SIGNAL go';
# Switching to connection 'deadlock_con2'.
# Reap FLUSH TABLES WITH READ LOCK.
unlock tables;
# Switching to connection 'deadlock_con1'.
# Reap SELECT.
i
#
# The same scenario with a slightly different order of events
# which emphasizes that setting correct deadlock detector weights
# for flush waits is important.
#
set debug_sync= 'RESET';
# Switching to connection 'deadlock_con2'.
set debug_sync='flush_tables_with_read_lock_after_acquire_locks SIGNAL parked WAIT_FOR go';
# The below FLUSH TABLES WITH READ LOCK should acquire
# SNW locks on t1 and t2 and wait on debug sync point.
# Sending:
flush tables t1, t2 with read lock;
# Switching to connection 'deadlock_con1'.
# Wait till FLUSH TABLE WITH READ LOCK stops.
set debug_sync='now WAIT_FOR parked';
# Start statement which will acquire SR metadata lock on t1, open
# it and then will block while trying to acquire SW lock on t2.
# Sending:
select * from t1 where i in (select j from t2 for update);
# Switching to connection 'deadlock_con3'.
# Wait till the above SELECT blocks.
# Resume FLUSH TABLES, so it tries to flush t1, thus creating
# a deadlock. This deadlock should be detected and resolved by
# backing-off SELECT. As a result FTWRL should be able to finish.
set debug_sync='now SIGNAL go';
# Switching to connection 'deadlock_con2'.
# Reap FLUSH TABLES WITH READ LOCK.
unlock tables;
# Switching to connection 'deadlock_con1'.
# Reap SELECT.
i
#
# Now a more complex scenario involving two connections
# waiting for MDL and one for TDC.
#
set debug_sync= 'RESET';
# Switching to connection 'deadlock_con1'.
# Start a statement which will acquire SR metadata lock on t2, open it
# and then stop, before trying to acquire SR on t1 and opening it.
set debug_sync='open_tables_after_open_and_process_table SIGNAL parked WAIT_FOR go';
# Sending:
select * from t2, t1;
# Switching to connection 'deadlock_con2'.
# Wait till the above SELECT stops.
set debug_sync='now WAIT_FOR parked';
# The below FLUSH TABLES WITH READ LOCK should acquire
# SNW locks on t2 and wait till SELECT closes t2.
# Sending:
flush tables t2 with read lock;
# Switching to connection 'deadlock_con3'.
# Wait until FLUSH TABLES WITH READ LOCK starts waiting
# for SELECT to close t2.
# The below DROP TABLES should acquire X lock on t1 and start
# waiting for X lock on t2.
# Sending:
drop tables t1, t2;
# Switching to connection 'default'.
# Wait until DROP TABLES starts waiting for X lock on t2.
# Resume SELECT, so it tries to acquire SR lock on t1 and blocks,
# creating a deadlock. This deadlock should be detected and resolved
# by backing-off SELECT. As a result, FTWRL should be able to finish.
set debug_sync='now SIGNAL go';
# Switching to connection 'deadlock_con2'.
# Reap FLUSH TABLES WITH READ LOCK.
# Unblock DROP TABLES.
unlock tables;
# Switching to connection 'deadlock_con3'.
# Reap DROP TABLES.
# Switching to connection 'deadlock_con1'.
# Reap SELECT. It should emit error about missing table.
ERROR 42S02: Table 'test.t2' doesn't exist
# Switching to connection 'default'.
set debug_sync= 'RESET';
#
# Test for a scenario in which FLUSH TABLES <list> WITH READ LOCK
# used to erroneously release metadata locks.
# 
drop tables if exists t1, t2;
set debug_sync= 'RESET';
create table t1(i int);
create table t2(j int);
# Switching to connection 'con2'.
set debug_sync='open_tables_after_open_and_process_table SIGNAL parked WAIT_FOR go';
# The below FLUSH TABLES <list> WITH READ LOCK should acquire
# SNW locks on t1 and t2, open table t1 and block on the debug
# sync point.
# Sending:
flush tables t1, t2 with read lock;
# Switching to connection 'con1'.
# Wait till FLUSH TABLES <list> WITH READ LOCK stops.
set debug_sync='now WAIT_FOR parked';
# Start a statement which will flush all tables and thus
# invalidate table t1 open by FLUSH TABLES <list> WITH READ LOCK.
# Sending:
flush tables;
# Switching to connection 'default'.
# Wait till the above FLUSH TABLES blocks.
# Resume FLUSH TABLES <list> WITH READ LOCK, so it tries to open t2
# discovers that its t1 is obsolete and tries to reopen all tables.
# Such reopen should not cause releasing of SNW metadata locks
# which would result in assertion failures.
set debug_sync='now SIGNAL go';
# Switching to connection 'con2'.
# Reap FLUSH TABLES <list> WITH READ LOCK.
unlock tables;
# Switching to connection 'con1'.
# Reap FLUSH TABLES.
# Clean-up.
# Switching to connection 'default'.
drop tables t1, t2;
set debug_sync= 'RESET';
#
# Test for bug #46748 "Assertion in MDL_context::wait_for_locks()
# on INSERT + CREATE TRIGGER".
#
drop tables if exists t1, t2, t3, t4, t5;
# Let us simulate scenario in which we open some tables from extended
# part of prelocking set but then encounter conflicting metadata lock,
# so have to back-off and wait for it to go away.
create table t1 (i int);
create table t2 (j int);
create table t3 (k int);
create table t4 (l int);
create trigger t1_bi before insert on t1 for each row
insert into t2 values (new.i);
create trigger t2_bi before insert on t2 for each row
insert into t3 values (new.j);
#
# Switching to connection 'con1root'.
lock tables t4 read;
#
# Switching to connection 'con2root'.
# Send :
rename table t3 to t5, t4 to t3;;
#
# Switching to connection 'default'.
# Wait until the above RENAME TABLE adds pending requests for exclusive
# metadata lock on its tables and blocks due to 't4' being used by LOCK
# TABLES.
# Send :
insert into t1 values (1);;
#
# Switching to connection 'con1root'.
# Wait until INSERT statement waits due to encountering pending
# exclusive metadata lock on 't3'.
unlock tables;
#
# Switching to connection 'con2root'.
# Reap RENAME TABLE.
#
# Switching to connection 'default'.
# Reap INSERT.
# Clean-up.
drop tables t1, t2, t3, t5;
#
# Bug#42546 - Backup: RESTORE fails, thinking it finds an existing table
#
DROP TABLE IF EXISTS t1;
set @save_log_output=@@global.log_output;
set global log_output=file;
#
# Test 1: CREATE TABLE
#
# Connection 2 
# Start insert on the not-yet existing table
# Wait after taking the MDL lock
SET DEBUG_SYNC= 'after_open_table_mdl_shared SIGNAL locked WAIT_FOR finish';
INSERT INTO t1 VALUES(1,"def");
# Connection 1
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Now INSERT has a MDL on the non-existent table t1.
#
# Continue the INSERT once CREATE waits for exclusive lock
SET DEBUG_SYNC= 'mdl_acquire_lock_wait SIGNAL finish';
# Try to create that table.
CREATE TABLE t1 (c1 INT, c2 VARCHAR(100), KEY(c1));
# Connection 2
# Insert fails
ERROR 42S02: Table 'test.t1' doesn't exist
# Connection 1
SET DEBUG_SYNC= 'RESET';
SHOW TABLES;
Tables_in_test
t1
DROP TABLE IF EXISTS t1;
#
# Test 2: CREATE TABLE LIKE
#
CREATE TABLE t2 (c1 INT, c2 VARCHAR(100), KEY(c1));
# Connection 2 
# Start insert on the not-yet existing table
# Wait after taking the MDL
SET DEBUG_SYNC= 'after_open_table_mdl_shared SIGNAL locked WAIT_FOR finish';
INSERT INTO t1 VALUES(1,"def");
# Connection 1
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Now INSERT has a MDL on the non-existent table t1.
#
# Continue the INSERT once CREATE waits for exclusive lock
SET DEBUG_SYNC= 'mdl_acquire_lock_wait SIGNAL finish';
# Try to create that table.
CREATE TABLE t1 LIKE t2;
# Connection 2
# Insert fails
ERROR 42S02: Table 'test.t1' doesn't exist
# Connection 1
SET DEBUG_SYNC= 'RESET';
SHOW TABLES;
Tables_in_test
t1
t2
DROP TABLE t2;
DROP TABLE IF EXISTS t1;
set global log_output=@save_log_output;
#
# Bug #46044 "MDL deadlock on LOCK TABLE + CREATE TABLE HIGH_PRIORITY
#             FOR UPDATE"
#
drop tables if exists t1, t2;
create table t1 (i int);
insert into t1 values(1);
# Let us check that we won't deadlock if during filling
# of I_S table we encounter conflicting metadata lock
# which owner is in its turn waiting for our connection.
lock tables t1 read;
# Switching to connection 'con46044_2'.
# Sending:
update t1 set i = 2;
# Switching to connection 'con46044'.
# Waiting until UPDATE t1 SET ... is blocked.
# Sending:
create table t2 select * from t1;;
# Switching to connection 'default'.
# Waiting until CREATE TABLE ... SELECT ... is blocked.
# First let us check that SHOW FIELDS/DESCRIBE doesn't
# gets blocked and emits and error.
show fields from t2;
ERROR HY000: Table 'test'.'t2' was skipped since its definition is being modified by concurrent DDL statement
# Now test for I_S query which reads only .FRMs.
#
# Query below should only emit a warning.
select column_name from information_schema.columns
where table_schema='test' and table_name='t2';
column_name
Warnings:
Warning	1684	Table 'test'.'t2' was skipped since its definition is being modified by concurrent DDL statement
# Finally, test for I_S query which does full-blown table open.
#
# Query below should not be blocked. Warning message should be
# stored in the 'table_comment' column.
select table_name, table_type, auto_increment, table_comment
from information_schema.tables where table_schema='test' and table_name='t2';
table_name	table_type	auto_increment	table_comment
t2	BASE TABLE	NULL	Table 'test'.'t2' was skipped since its definition is being modified by concurrent DDL statement
Warnings:
Warning	1684	Table 'test'.'t2' was skipped since its definition is being modified by concurrent DDL statement
# Switching to connection 'default'.
unlock tables;
# Switching to connection 'con46044'.
# Reaping CREATE TABLE ... SELECT ... .
drop table t2;
# Reaping UPDATE t1 statement
#
# Let us also check that queries to I_S wait for conflicting metadata
# locks to go away instead of skipping table with a warning in cases
# when deadlock is not possible. This is a nice thing from compatibility
# and ease of use points of view.
#
# We check same three queries to I_S in this new situation.
# Switching to connection 'con46044_2'.
lock tables t1 read;
# Switching to connection 'con46044_3'.
# Sending:
update t1 set i = 3;
# Switching to connection 'con46044'.
# Waiting until UPDATE t1 SET ... is blocked.
# Sending:
create table t2 select * from t1;;
# Switching to connection 'default'.
# Waiting until CREATE TABLE ... SELECT ... is blocked.
# Let us check that SHOW FIELDS/DESCRIBE gets blocked.
# Sending:
show fields from t2;;
# Switching to connection 'con46044_2'.
# Wait until SHOW FIELDS gets blocked.
unlock tables;
# Switching to connection 'con46044'.
# Reaping CREATE TABLE ... SELECT ... .
# Switching to connection 'default'.
# Reaping SHOW FIELDS ...
Field	Type	Null	Key	Default	Extra
i	int(11)	YES		NULL	
drop table t2;
# Reaping UPDATE t1 statement
# Switching to connection 'con46044_2'.
lock tables t1 read;
# Switching to connection 'con46044_3'.
# Sending:
update t1 set i = 4;
# Switching to connection 'con46044'.
# Waiting until UPDATE t1 SET ... is blocked.
# Sending:
create table t2 select * from t1;;
# Switching to connection 'default'.
# Waiting until CREATE TABLE ... SELECT ... is blocked.
# Check that I_S query which reads only .FRMs gets blocked.
# Sending:
select column_name from information_schema.columns where table_schema='test' and table_name='t2';;
# Switching to connection 'con46044_2'.
# Wait until SELECT COLUMN_NAME FROM I_S.COLUMNS  gets blocked.
unlock tables;
# Switching to connection 'con46044'.
# Reaping CREATE TABLE ... SELECT ... .
# Switching to connection 'default'.
# Reaping SELECT COLUMN_NAME FROM I_S.COLUMNS
column_name
i
drop table t2;
# Reaping UPDATE t1 statement
# Switching to connection 'con46044_2'.
lock tables t1 read;
# Switching to connection 'con46044_3'.
# Sending:
update t1 set i = 5;
# Switching to connection 'con46044'.
# Waiting until UPDATE t1 SET ... is blocked.
# Sending:
create table t2 select * from t1;;
# Switching to connection 'default'.
# Waiting until CREATE TABLE ... SELECT ... is blocked.
# Finally, check that I_S query which does full-blown table open
# also gets blocked.
# Sending:
select table_name, table_type, auto_increment, table_comment from information_schema.tables where table_schema='test' and table_name='t2';;
# Switching to connection 'con46044_2'.
# Wait until SELECT ... FROM I_S.TABLES gets blocked.
unlock tables;
# Switching to connection 'con46044'.
# Reaping CREATE TABLE ... SELECT ... .
# Switching to connection 'default'.
# Reaping SELECT ... FROM I_S.TABLES
table_name	table_type	auto_increment	table_comment
t2	BASE TABLE	NULL	
drop table t2;
# Reaping UPDATE t1 statement
# Switching to connection 'default'.
# Clean-up.
drop table t1;
#
# Test for bug #46273 "MySQL 5.4.4 new MDL: Bug#989 is not fully fixed
#                      in case of ALTER".
#
drop table if exists t1;
set debug_sync= 'RESET';
create table t1 (c1 int primary key, c2 int, c3 int);
insert into t1 values (1,1,0),(2,2,0),(3,3,0),(4,4,0),(5,5,0);
begin;
select * from t1 where c2 = 3;
c1	c2	c3
3	3	0
#
# Switching to connection 'con46273'.
set debug_sync='alter_table_copy_after_lock_upgrade SIGNAL alter_table_locked WAIT_FOR alter_go';
alter table t1 add column e int, rename to t2;;
#
# Switching to connection 'default'.
set debug_sync='now WAIT_FOR alter_table_locked';
set debug_sync='mdl_acquire_lock_wait SIGNAL alter_go';
# The below statement should get ER_LOCK_DEADLOCK error
# (i.e. it should not allow ALTER to proceed, and then
# fail due to 't1' changing its name to 't2').
update t1 set c3=c3+1 where c2 = 3;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
#
# Switching to connection 'con46273'.
# Reap ALTER TABLE.
#
# Switching to connection 'default'.
# Clean-up.
set debug_sync= 'RESET';
drop table t2;
#
# Test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK
#                      and DML".
#
drop tables if exists t1;
create table t1 (i int);
# Switching to connection 'con46673'.
begin;
insert into t1 values (1);
# Switching to connection 'default'.
# Statement below should not get blocked. And if after some
# changes to code it is there should not be a deadlock between
# it and transaction from connection 'con46673'.
flush tables with read lock;
unlock tables;
# Switching to connection 'con46673'.
delete from t1 where i = 1;
commit;
# Switching to connection 'default'.
# Clean-up
drop table t1;
#
# Bug#48210 FLUSH TABLES WITH READ LOCK deadlocks 
#           against concurrent CREATE PROCEDURE
#
# Test 1: CREATE PROCEDURE
# Connection 1
# Start CREATE PROCEDURE and open mysql.proc
SET DEBUG_SYNC= 'after_open_table_mdl_shared SIGNAL table_opened WAIT_FOR grlwait';
CREATE PROCEDURE p1() SELECT 1;
# Connection 2
SET DEBUG_SYNC= 'now WAIT_FOR table_opened';
# Check that FLUSH must wait to get the GRL
# and let CREATE PROCEDURE continue
SET DEBUG_SYNC= 'mdl_acquire_lock_wait SIGNAL grlwait';
FLUSH TABLES WITH READ LOCK;
# Connection 1
# Connection 2
UNLOCK TABLES;
# Connection 1
SET DEBUG_SYNC= 'RESET';
# Test 2: DROP PROCEDURE
# Start DROP PROCEDURE and open tables
SET DEBUG_SYNC= 'after_open_table_mdl_shared SIGNAL table_opened WAIT_FOR grlwait';
DROP PROCEDURE p1;
# Connection 2
SET DEBUG_SYNC= 'now WAIT_FOR table_opened';
# Check that FLUSH must wait to get the GRL
# and let DROP PROCEDURE continue
SET DEBUG_SYNC= 'mdl_acquire_lock_wait SIGNAL grlwait';
FLUSH TABLES WITH READ LOCK;
# Connection 1
# Once FLUSH TABLES WITH READ LOCK starts waiting
# DROP PROCEDURE will be waked up and will drop
# procedure. Global read lock will be granted after
# this statement ends.
#
# Reaping DROP PROCEDURE.
# Connection 2
# Reaping FTWRL.
UNLOCK TABLES;
# Connection 1
SET DEBUG_SYNC= 'RESET';
#
# Bug#50786 Assertion `thd->mdl_context.trans_sentinel() == __null' 
#           failed in open_ltable()
#
# Supress warnings written to the log file
call mtr.add_suppression("Wait on a lock was aborted due to a pending exclusive lock");
DROP TABLE IF EXISTS t1, t2;
CREATE TABLE t1 (i INT);
CREATE TABLE t2 (i INT);
SET @old_general_log= @@global.general_log;
SET @@global.general_log= 1;
SET @old_log_output= @@global.log_output;
SET @@global.log_output= 'TABLE';
SET @old_sql_log_off= @@session.sql_log_off;
SET @@session.sql_log_off= 1;
# connection: con1
HANDLER t1 OPEN;
# connection: con3
SET @@session.sql_log_off= 1;
# connection: con2
SET DEBUG_SYNC= 'thr_multi_lock_after_thr_lock SIGNAL parked WAIT_FOR go';
# Sending:
SELECT 1;
# connection: con3
SET DEBUG_SYNC= 'now WAIT_FOR parked';
# connection: con1
# Sending:
SELECT 1;
# connection: con3
ALTER TABLE t1 ADD COLUMN j INT;
# connection: default
SET DEBUG_SYNC= 'now SIGNAL go';
# connection: con1
# Reaping SELECT 1
1
1
HANDLER t1 CLOSE;
# connection: con2
# Reaping SELECT 1
1
1
# connection: default
DROP TABLE t1, t2;
SET DEBUG_SYNC= 'RESET';
SET @@global.general_log= @old_general_log;
SET @@global.log_output= @old_log_output;
SET @@session.sql_log_off= @old_sql_log_off;
#
# Additional coverage for bug #50913 "Deadlock between
# open_and_lock_tables_derived and MDL". The main test
# case is in lock_multi.test
#
drop table if exists t1;
set debug_sync= 'RESET';
create table t1 (i int) engine=InnoDB;
# Switching to connection 'con50913_1'.
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL parked WAIT_FOR go';
# Sending:
alter table t1 add column j int, ALGORITHM=COPY;
# Switching to connection 'default'.
# Wait until ALTER TABLE gets blocked on a sync point after
# acquiring thr_lock.c lock.
set debug_sync= 'now WAIT_FOR parked';
# The below statement should wait on MDL lock and not deadlock on
# thr_lock.c lock.
# Sending:
truncate table t1;
# Switching to connection 'con50913_2'.
# Wait until TRUNCATE TABLE is blocked on MDL lock.
# Unblock ALTER TABLE.
set debug_sync= 'now SIGNAL go';
# Switching to connection 'con50913_1'.
# Reaping ALTER TABLE.
# Switching to connection 'default'.
# Reaping TRUNCATE TABLE.
set debug_sync= 'RESET';
drop table t1;
#
# Test for bug #50998 "Deadlock in MDL code during test
#                      rqg_mdl_stability".
# Also provides coverage for the case when addition of
# waiting statement adds several loops in the waiters
# graph and therefore several searches for deadlock
# should be performed.
drop table if exists t1;
set debug_sync= 'RESET';
create table t1 (i int);
# Switching to connection 'con1'.
begin;
select * from t1;
i
# Switching to connection 'con2'.
begin;
select * from t1;
i
# Switching to connection 'default'.
# Start ALTER TABLE which will acquire SNW lock and
# table lock and get blocked on sync point.
set debug_sync= 'alter_table_copy_after_lock_upgrade SIGNAL parked WAIT_FOR go';
# Sending:
alter table t1 add column j int;
# Switching to connection 'con1'.
# Wait until ALTER TABLE gets blocked on a sync point.
set debug_sync= 'now WAIT_FOR parked';
# Sending:
insert into t1 values (1);
# Switching to connection 'con2'.
# Sending:
insert into t1 values (1);
# Switching to connection 'con3'.
# Wait until both 'con1' and 'con2' are blocked trying to acquire
# SW lock on the table.
# Unblock ALTER TABLE. Since it will try to upgrade SNW to X lock
# deadlock with two loops in waiting graph will occur. Both loops
# should be found and DML statements in both 'con1' and 'con2'
# should be aborted with ER_LOCK_DEADLOCK errors.
set debug_sync= 'now SIGNAL go';
# Switching to connection 'con1'.
# Reaping INSERT. It should end with ER_LOCK_DEADLOCK error and
# not wait indefinitely (as it happened before the bugfix).
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
commit;
# Switching to connection 'con2'.
# Reaping INSERT.
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
commit;
# Switching to connection 'default'.
# Reap ALTER TABLE.
set debug_sync= 'RESET';
drop table t1;
#
# Bug#42643: InnoDB does not support replication of TRUNCATE TABLE
#
# Ensure that a acquired lock is not given up due to a conflict.
#
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a INT) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1),(2),(3);
# Connection: con1
LOCK TABLES t1 WRITE;
SET debug_sync='upgrade_lock_for_truncate SIGNAL parked_truncate WAIT_FOR go_truncate';
TRUNCATE TABLE t1;
# Connection: default
SET debug_sync='now WAIT_FOR parked_truncate';
# Connection: con2
SET debug_sync='after_open_table_ignore_flush SIGNAL parked_show WAIT_FOR go_show';
SHOW FIELDS FROM t1;
# Connection: default
SET debug_sync='now WAIT_FOR parked_show';
# Connection: con3
SET debug_sync='after_flush_unlock SIGNAL parked_flush WAIT_FOR go_flush';
FLUSH TABLES t1;
# Connection: default
SET debug_sync='now WAIT_FOR parked_flush';
SET debug_sync='now SIGNAL go_truncate';
# Ensure that truncate waits for a exclusive lock
SET debug_sync= 'now SIGNAL go_show';
# Connection: con1 (TRUNCATE)
# Reaping...
UNLOCK TABLES;
# Connection: con2 (SHOW FIELDS FROM t1)
# Reaping...
Field	Type	Null	Key	Default	Extra
a	int(11)	YES		NULL	
# Connection: default
SET debug_sync= 'now SIGNAL go_flush';
# Connection: con3 (FLUSH TABLES t1)
# Reaping...
# Connection: default
SET debug_sync= 'RESET';
DROP TABLE t1;
#
# Bug#52856 concurrent show columns or show full columns causes a crash!!!
#
CREATE TABLE t1(a CHAR(255));
SET DEBUG_SYNC= "get_schema_column SIGNAL waiting WAIT_FOR completed";
SHOW FULL COLUMNS FROM t1;
SET DEBUG_SYNC= "now WAIT_FOR waiting";
SHOW FULL COLUMNS FROM t1;
Field	Type	Collation	Null	Key	Default	Extra	Privileges	Comment
a	char(255)	latin1_swedish_ci	YES		NULL		#	
SET DEBUG_SYNC= "now SIGNAL completed";
Field	Type	Collation	Null	Key	Default	Extra	Privileges	Comment
a	char(255)	latin1_swedish_ci	YES		NULL		#	
DROP TABLE t1;
#
# Tests for schema-scope locks
#
DROP DATABASE IF EXISTS db1;
DROP DATABASE IF EXISTS db2;
# Test 1: 
# CREATE DATABASE blocks database DDL on the same database, but
# not database DDL on different databases. Tests X vs X lock.
#
# Connection default
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
CREATE DATABASE db1;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
CREATE DATABASE db1;
# Connection con3
CREATE DATABASE db2;
ALTER DATABASE db2 DEFAULT CHARACTER SET utf8;
DROP DATABASE db2;
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: CREATE DATABASE db1
# Connection con2
# Reaping: CREATE DATABASE db1
ERROR HY000: Can't create database 'db1'; database exists
# Test 2:
# ALTER DATABASE blocks database DDL on the same database, but
# not database DDL on different databases. Tests X vs X lock.
#
# Connection default
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
ALTER DATABASE db1 DEFAULT CHARACTER SET utf8;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
ALTER DATABASE db1 DEFAULT CHARACTER SET utf8;
# Connection con3
CREATE DATABASE db2;
ALTER DATABASE db2 DEFAULT CHARACTER SET utf8;
DROP DATABASE db2;
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: ALTER DATABASE db1 DEFAULT CHARACTER SET utf8
# Connection con2
# Reaping: ALTER DATABASE db1 DEFAULT CHARACTER SET utf8
# Connection default
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
ALTER DATABASE db1 DEFAULT CHARACTER SET utf8;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
DROP DATABASE db1;
# Connection con3
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: ALTER DATABASE db1 DEFAULT CHARACTER SET utf8
# Connection con2
# Reaping: DROP DATABASE db1
CREATE DATABASE db1;
# Test 3:
# Two ALTER..UPGRADE of the same database are mutually exclusive, but
# two ALTER..UPGRADE of different databases are not. Tests X vs X lock.
#
# Connection default
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
ALTER DATABASE `#mysql50#a-b-c` UPGRADE DATA DIRECTORY NAME;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
ALTER DATABASE `#mysql50#a-b-c` UPGRADE DATA DIRECTORY NAME;
# Connection con3
ALTER DATABASE `#mysql50#a-b-c-d` UPGRADE DATA DIRECTORY NAME;
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: ALTER DATABASE '#mysql50#a-b-c' UPGRADE DATA DIRECTORY NAME
# Connection con2
# Reaping: ALTER DATABASE '#mysql50#a-b-c' UPGRADE DATA DIRECTORY NAME
ERROR 42000: Unknown database '#mysql50#a-b-c'
DROP DATABASE `a-b-c`;
DROP DATABASE `a-b-c-d`;
# Test 4:
# DROP DATABASE blocks database DDL on the same database, but
# not database DDL on different databases. Tests X vs X lock.
#
# Connection default
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
DROP DATABASE db1;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
DROP DATABASE db1;
# Connection con3
CREATE DATABASE db2;
ALTER DATABASE db2 DEFAULT CHARACTER SET utf8;
DROP DATABASE db2;
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: DROP DATABASE db1
# Connection con2
# Reaping: DROP DATABASE db1
ERROR HY000: Can't drop database 'db1'; database doesn't exist
# Connection default
CREATE DATABASE db1;
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
DROP DATABASE db1;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
ALTER DATABASE db1 DEFAULT CHARACTER SET utf8;
# Connection con3
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: DROP DATABASE db1
# Connection con2
# Reaping: ALTER DATABASE db1 DEFAULT CHARACTER SET utf8
Got one of the listed errors
# Test 5:
# Locked database name prevents CREATE of tables in that database.
# Tests X vs IX lock.
#
# Connection default
CREATE DATABASE db1;
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
DROP DATABASE db1;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
CREATE TABLE db1.t1 (a INT);
# Connection con3
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: DROP DATABASE db1
# Connection con2
# Reaping: CREATE TABLE db1.t1 (a INT)
ERROR 42000: Unknown database 'db1'
# Test 6:
# Locked database name prevents RENAME of tables to/from that database.
# Tests X vs IX lock.
#
# Connection default
CREATE DATABASE db1;
CREATE TABLE db1.t1 (a INT);
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
DROP DATABASE db1;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
RENAME TABLE db1.t1 TO test.t1;
# Connection con3
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: DROP DATABASE db1
# Connection con2
# Reaping: RENAME TABLE db1.t1 TO test.t1
ERROR 42S02: Table 'db1.t1' doesn't exist
# Connection default
CREATE DATABASE db1;
CREATE TABLE test.t2 (a INT);
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
DROP DATABASE db1;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
RENAME TABLE test.t2 TO db1.t2;
# Connection con3
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: DROP DATABASE db1
# Connection con2
# Reaping: RENAME TABLE test.t2 TO db1.t2
Got one of the listed errors
DROP TABLE test.t2;
# Test 7:
# Locked database name prevents DROP of tables in that database.
# Tests X vs IX lock.
#
# Connection default
CREATE DATABASE db1;
CREATE TABLE db1.t1 (a INT);
SET DEBUG_SYNC= 'after_wait_locked_schema_name SIGNAL locked WAIT_FOR blocked';
# Sending:
DROP DATABASE db1;
# Connection con2
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# Sending:
DROP TABLE db1.t1;
# Connection con3
SET DEBUG_SYNC= 'now SIGNAL blocked';
# Connection default
# Reaping: DROP DATABASE db1
# Connection con2
# Reaping: DROP TABLE db1.t1
ERROR 42S02: Unknown table 'db1.t1'
# Connection default
SET DEBUG_SYNC= 'RESET';
#
# End of tests for schema-scope locks
#
#
# Tests of granted global S lock (FLUSH TABLE WITH READ LOCK)
#
CREATE DATABASE db1;
CREATE TABLE db1.t1(a INT);
# Connection default
FLUSH TABLE WITH READ LOCK;
# Connection con2
CREATE TABLE db1.t2(a INT);
# Connection default
UNLOCK TABLES;
# Connection con2
# Reaping CREATE TABLE db1.t2(a INT)
# Connection default
FLUSH TABLE WITH READ LOCK;
# Connection con2
ALTER DATABASE db1 DEFAULT CHARACTER SET utf8;
# Connection default
UNLOCK TABLES;
# Connection con2
# Reaping ALTER DATABASE db1 DEFAULT CHARACTER SET utf8
# Connection default
FLUSH TABLE WITH READ LOCK;
# Connection con2
FLUSH TABLE WITH READ LOCK;
UNLOCK TABLES;
# Connection default
UNLOCK TABLES;
DROP DATABASE db1;
#
# Bug#56292 Deadlock with ALTER TABLE and MERGE tables
#
DROP TABLE IF EXISTS t1, t2, m1;
CREATE TABLE t1(a INT) engine=MyISAM;
CREATE TABLE t2(a INT) engine=MyISAM;
CREATE TABLE m1(a INT) engine=MERGE UNION=(t1, t2);
INSERT INTO t1 VALUES (1), (2);
INSERT INTO t2 VALUES (3), (4);
# Connection con1
# We need EXECUTE 2 since ALTER TABLE does SU => SNW => X and we want
# to stop at the second upgrade.
SET DEBUG_SYNC= 'mdl_upgrade_lock SIGNAL upgrade WAIT_FOR continue EXECUTE 2';
# Sending:
ALTER TABLE m1 engine=MERGE UNION=(t2, t1);
# Connection con2
# Waiting for ALTER TABLE to try lock upgrade
SET DEBUG_SYNC= 'now WAIT_FOR upgrade';
SET DEBUG_SYNC= 'now SIGNAL continue';
SET DEBUG_SYNC= 'now WAIT_FOR upgrade';
# Sending:
DELETE FROM t2 WHERE a = 3;
# Connection default
# Check that DELETE is waiting on a metadata lock and not a table lock.
# Now that DELETE blocks on a metadata lock, we should be able to do
# SELECT * FROM m1 here. SELECT used to be blocked by a DELETE table
# lock request.
SELECT * FROM m1;
a
1
2
3
4
# Resuming ALTER TABLE
SET DEBUG_SYNC= 'now SIGNAL continue';
# Connection con1
# Reaping: ALTER TABLE m1 engine=MERGE UNION=(t2, t1)
# Connection con2
# Reaping: DELETE FROM t2 WHERE a = 3
# Connection default
DROP TABLE m1, t1, t2;
SET DEBUG_SYNC= 'RESET';
