mariadb/mysql-test/t/read_only.test
Sergei Golubchik 4361c8645b MDEV-136 Non-blocking "set read_only"
backport dmitry.shulga@oracle.com-20120209125742-w7hdxv0103ymb8ko from mysql-trunk:

  Patch for bug#11764747 (formerly known as 57612): SET GLOBAL READ_ONLY=1 cannot
  progress when a table is locked with LOCK TABLES.
  
  The reason for the bug was that mysql server makes a flush of all open tables
  during handling of statement 'SET GLOBAL READ_ONLY=1'. Therefore if some of
  these tables were locked by "LOCK TABLE ... READ" from a different connection,
  then execution of statement 'SET GLOBAL READ_ONLY=1' would be waiting for
  the lock for such table even if the table was locked in a compatible read mode.
  
  Flushing of all open tables before setting of read_only system variable
  is inherited from 5.1 implementation since this was the only possible approach
  to ensure that there isn't any pending write operations on open tables.
  
  Start from version 5.5 and above such behaviour is guaranteed by the fact
  that we acquire global_read_lock before setting read_only flag. Since
  acquiring of global_read_lock is successful only when there isn't any 
  active write operation then we can remove flushing of open tables from
  processing of SET GLOBAL READ_ONLY=1.
  
  This modification changes the server behavior so that read locks held
  by other connections (LOCK TABLE ... READ) no longer will block attempts
  to enable read_only.
2012-06-04 17:39:28 +02:00

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# Test of the READ_ONLY global variable:
# check that it blocks updates unless they are only on temporary tables.
# should work with embedded server after mysqltest is fixed
--source include/not_embedded.inc
set @start_read_only= @@global.read_only;
# Save the initial number of concurrent sessions
--source include/count_sessions.inc
--disable_warnings
DROP TABLE IF EXISTS t1,t2,t3;
--enable_warnings
# READ_ONLY does nothing to SUPER users
# so we use a non-SUPER one:
grant CREATE, SELECT, DROP on *.* to test@localhost;
--echo connect (con1,localhost,test,,test);
connect (con1,localhost,test,,test);
--echo connection default;
connection default;
set global read_only=0;
--echo connection con1;
connection con1;
create table t1 (a int);
insert into t1 values(1);
create table t2 select * from t1;
--echo connection default;
connection default;
set global read_only=1;
# We check that SUPER can:
create table t3 (a int);
drop table t3;
--echo connection con1;
connection con1;
select @@global.read_only;
--error ER_OPTION_PREVENTS_STATEMENT
create table t3 (a int);
--error ER_OPTION_PREVENTS_STATEMENT
insert into t1 values(1);
# if a statement, after parse stage, looks like it will update a
# non-temp table, it will be rejected, even if at execution it would
# have turned out that 0 rows would be updated
--error ER_OPTION_PREVENTS_STATEMENT
update t1 set a=1 where 1=0;
# multi-update is special (see sql_parse.cc) so we test it
--error ER_OPTION_PREVENTS_STATEMENT
update t1,t2 set t1.a=t2.a+1 where t1.a=t2.a;
# check multi-delete to be sure
--error ER_OPTION_PREVENTS_STATEMENT
delete t1,t2 from t1,t2 where t1.a=t2.a;
# With temp tables updates should be accepted:
create temporary table t3 (a int);
create temporary table t4 (a int) select * from t3;
insert into t3 values(1);
insert into t4 select * from t3;
# a non-temp table updated:
--error ER_OPTION_PREVENTS_STATEMENT
update t1,t3 set t1.a=t3.a+1 where t1.a=t3.a;
# no non-temp table updated (just swapped):
update t1,t3 set t3.a=t1.a+1 where t1.a=t3.a;
update t4,t3 set t4.a=t3.a+1 where t4.a=t3.a;
--error ER_OPTION_PREVENTS_STATEMENT
delete t1 from t1,t3 where t1.a=t3.a;
delete t3 from t1,t3 where t1.a=t3.a;
delete t4 from t3,t4 where t4.a=t3.a;
# and even homonymous ones
create temporary table t1 (a int);
insert into t1 values(1);
update t1,t3 set t1.a=t3.a+1 where t1.a=t3.a;
delete t1 from t1,t3 where t1.a=t3.a;
drop table t1;
--error ER_OPTION_PREVENTS_STATEMENT
insert into t1 values(1);
#
# Bug#11733 COMMITs should not happen if read-only is set
#
# LOCK TABLE ... WRITE / READ_ONLY
# - is an error in the same connection
# - is ok in a different connection
--echo connection default;
connection default;
set global read_only=0;
lock table t1 write;
--echo connection con1;
connection con1;
lock table t2 write;
--echo connection default;
connection default;
--error ER_LOCK_OR_ACTIVE_TRANSACTION
set global read_only=1;
unlock tables ;
# The following call blocks until con1 releases the write lock.
# Blocking is expected.
--echo send set global read_only=1;
send set global read_only=1;
--echo connection con1;
connection con1;
select @@global.read_only;
unlock tables ;
let $wait_condition= SELECT @@global.read_only= 1;
--source include/wait_condition.inc
select @@global.read_only;
--echo connection default;
connection default;
--echo reap;
reap;
# LOCK TABLE ... READ / READ_ONLY
# - is an error in the same connection
# - is ok in a different connection
--echo connection default;
connection default;
set global read_only=0;
lock table t1 read;
--echo connection con1;
connection con1;
lock table t2 read;
--echo connection default;
connection default;
--error ER_LOCK_OR_ACTIVE_TRANSACTION
set global read_only=1;
unlock tables ;
# after unlock tables in current connection
# the next command must be executed successfully
set global read_only=1;
select @@global.read_only;
--echo connection con1;
connection con1;
select @@global.read_only;
unlock tables ;
--echo connection default;
connection default;
# pending transaction / READ_ONLY
# - is an error in the same connection
# - is ok in a different connection
--echo connection default;
connection default;
set global read_only=0;
BEGIN;
--echo connection con1;
connection con1;
BEGIN;
--echo connection default;
connection default;
--error ER_LOCK_OR_ACTIVE_TRANSACTION
set global read_only=1;
ROLLBACK;
set global read_only=1;
--echo connection con1;
connection con1;
select @@global.read_only;
ROLLBACK;
# Verify that FLUSH TABLES WITH READ LOCK do not block READ_ONLY
# - in the same SUPER connection
# - in another SUPER connection
--echo connection default;
connection default;
set global read_only=0;
flush tables with read lock;
set global read_only=1;
unlock tables;
--echo connect (root2,localhost,root,,test);
connect (root2,localhost,root,,test);
--echo connection default;
connection default;
set global read_only=0;
flush tables with read lock;
--echo connection root2;
connection root2;
set global read_only=1;
--echo connection default;
connection default;
select @@global.read_only;
unlock tables;
disconnect root2;
# Bug#22077 DROP TEMPORARY TABLE fails with wrong error if read_only is set
#
# check if DROP TEMPORARY on a non-existing temporary table returns the right
# error
--error ER_BAD_TABLE_ERROR
drop temporary table ttt;
# check if DROP TEMPORARY TABLE IF EXISTS produces a warning with read_only set
drop temporary table if exists ttt;
#
# Cleanup
#
--echo connection default;
connection default;
set global read_only=0;
disconnect con1;
drop table t1,t2;
drop user test@localhost;
--echo #
--echo # Bug#27440 read_only allows create and drop database
--echo #
set global read_only= 1;
--disable_warnings
drop database if exists mysqltest_db1;
drop database if exists mysqltest_db2;
--enable_warnings
delete from mysql.user where User like 'mysqltest_%';
delete from mysql.db where User like 'mysqltest_%';
delete from mysql.tables_priv where User like 'mysqltest_%';
delete from mysql.columns_priv where User like 'mysqltest_%';
flush privileges;
grant all on mysqltest_db2.* to `mysqltest_u1`@`%`;
create database mysqltest_db1;
grant all on mysqltest_db1.* to `mysqltest_u1`@`%`;
flush privileges;
--echo connect (con_bug27440,127.0.0.1,mysqltest_u1,,test,MASTER_MYPORT,);
connect (con_bug27440,127.0.0.1,mysqltest_u1,,test,$MASTER_MYPORT,);
--echo connection con_bug27440;
connection con_bug27440;
--error ER_OPTION_PREVENTS_STATEMENT
create database mysqltest_db2;
show databases like '%mysqltest_db2%';
--error ER_OPTION_PREVENTS_STATEMENT
drop database mysqltest_db1;
--echo disconnect con_bug27440;
disconnect con_bug27440;
--echo connection default;
connection default;
delete from mysql.user where User like 'mysqltest_%';
delete from mysql.db where User like 'mysqltest_%';
delete from mysql.tables_priv where User like 'mysqltest_%';
delete from mysql.columns_priv where User like 'mysqltest_%';
flush privileges;
drop database mysqltest_db1;
set global read_only= @start_read_only;
# Wait till all disconnects are completed
--source include/wait_until_count_sessions.inc