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BUG#9953: CONVERT_TZ requires mysql.time_zone_name to be locked

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The problem was that some facilities (like CONVERT_TZ() function or
server HELP statement) may require implicit access to some tables in
'mysql' database.  This access was done by ordinary means of adding
such tables to the list of tables the query is going to open.
However, if we issued LOCK TABLES before that, we would get "table
was not locked" error trying to open such implicit tables.

The solution is to treat certain tables as MySQL system tables, like
we already do for mysql.proc.  Such tables may be opened for reading
at any moment regardless of any locks in effect.  The cost of this is
that system table may be locked for writing only together with other
system tables, it is disallowed to lock system tables for writing and
have any other lock on any other table.

After this patch the following tables are treated as MySQL system
tables:
  mysql.help_category
  mysql.help_keyword
  mysql.help_relation
  mysql.help_topic
  mysql.proc (it already was)
  mysql.time_zone
  mysql.time_zone_leap_second
  mysql.time_zone_name
  mysql.time_zone_transition
  mysql.time_zone_transition_type

These tables are now opened with open_system_tables_for_read() and
closed with close_system_tables(), or one table may be opened with
open_system_table_for_update() and closed with close_thread_tables()
(the latter is used for mysql.proc table, which is updated as part of
normal MySQL server operation).  These functions may be used when
some tables were opened and locked already.

NOTE: online update of time zone tables is not possible during
replication, because there's no time zone cache flush neither on LOCK
TABLES, nor on FLUSH TABLES, so the master may serve stale time zone
data from cache, while on slave updated data will be loaded from the
time zone tables.
This commit is contained in:
kroki/tomash@moonlight.home
2007-03-09 13:12:31 +03:00
parent 8b07431927
commit c19affef54
35 changed files with 430 additions and 365 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
mysql-test/r/help.result
View File

@ -257,3 +257,12 @@ delete from mysql.help_relation where help_keyword_id=@keyword1_id and help_topi
delete from mysql.help_relation where help_keyword_id=@keyword2_id and help_topic_id=@topic1_id;
delete from mysql.help_relation where help_keyword_id=@keyword3_id and help_topic_id=@topic3_id;
delete from mysql.help_relation where help_keyword_id=@keyword3_id and help_topic_id=@topic4_id;
End of 4.1 tests.
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (i INT);
LOCK TABLES t1 WRITE;
HELP no_such_topic;
name is_it_category
UNLOCK TABLES;
DROP TABLE t1;
End of 5.1 tests.

21
mysql-test/r/lock.result
View File

@ -68,6 +68,7 @@ ERROR HY000: Table 't2' was locked with a READ lock and can't be updated
delete t2 from t1,t2 where t1.a=t2.a;
ERROR HY000: Table 't2' was locked with a READ lock and can't be updated
drop table t1,t2;
End of 4.1 tests.
drop table if exists t1;
create table t1 (a int);
lock table t1 write;
@ -75,3 +76,23 @@ flush tables with read lock;
ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
unlock tables;
drop table t1;
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (i INT);
LOCK TABLES mysql.time_zone READ, mysql.proc READ, t1 READ;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone READ, mysql.proc READ, t1 WRITE;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone READ, mysql.proc READ;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone READ, mysql.proc WRITE, t1 READ;
ERROR HY000: You can't combine write-locking of system tables with other tables or lock types
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE, t1 READ;
ERROR HY000: You can't combine write-locking of system tables with other tables or lock types
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE, t1 WRITE;
ERROR HY000: You can't combine write-locking of system tables with other tables or lock types
LOCK TABLES mysql.time_zone READ, mysql.proc WRITE;
ERROR HY000: You can't combine write-locking of system tables with other tables or lock types
DROP TABLE t1;
End of 5.1 tests.

4
mysql-test/r/sp-error.result
View File

@ -292,9 +292,9 @@ call p()|
unlock tables|
drop procedure p|
lock tables t1 read, mysql.proc write|
ERROR HY000: You can't combine write-locking of system 'mysql.proc' table with other tables
ERROR HY000: You can't combine write-locking of system tables with other tables or lock types
lock tables mysql.proc write, mysql.user write|
ERROR HY000: You can't combine write-locking of system 'mysql.proc' table with other tables
ERROR HY000: You can't combine write-locking of system tables with other tables or lock types
lock tables t1 read, mysql.proc read|
unlock tables|
lock tables mysql.proc write|

11
mysql-test/r/timezone2.result
View File

@ -285,3 +285,14 @@ ldt ldt2
drop table t1;
drop function f1;
SET GLOBAL log_bin_trust_function_creators = 0;
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (t TIMESTAMP);
INSERT INTO t1 VALUES (NULL), (NULL);
LOCK TABLES t1 WRITE;
SELECT CONVERT_TZ(NOW(), 'UTC', 'Europe/Moscow') IS NULL;
CONVERT_TZ(NOW(), 'UTC', 'Europe/Moscow') IS NULL
0
UPDATE t1 SET t = CONVERT_TZ(t, 'UTC', 'Europe/Moscow');
UNLOCK TABLES;
DROP TABLE t1;
End of 5.1 tests

7
mysql-test/r/view.result
View File

@ -900,6 +900,7 @@ drop view v1;
drop table t1;
create table t1 (col1 int);
create table t2 (col1 int);
create table t3 (col1 datetime not null);
create view v1 as select * from t1;
create view v2 as select * from v1;
create view v3 as select v2.col1 from v2,t2 where v2.col1 = t2.col1;
@ -1004,8 +1005,8 @@ ERROR HY000: The definition of table 'v2' prevents operation INSERT on table 'v3
insert into v3 (col1) values ((select CONVERT_TZ('20050101000000','UTC','MET') from v2));
ERROR HY000: The definition of table 'v2' prevents operation INSERT on table 'v3'.
insert into v3 (col1) values ((select CONVERT_TZ('20050101000000','UTC','MET') from t2));
insert into mysql.time_zone values ('', (select CONVERT_TZ('20050101000000','UTC','MET') from t2));
ERROR 23000: Column 'Use_leap_seconds' cannot be null
insert into t3 values ((select CONVERT_TZ('20050101000000','UTC','MET') from t2));
ERROR 23000: Column 'col1' cannot be null
create algorithm=temptable view v4 as select * from t1;
insert into t1 values (1),(2),(3);
insert into t1 (col1) values ((select max(col1) from v4));
@ -1017,7 +1018,7 @@ NULL
3
3
drop view v4,v3,v2,v1;
drop table t1,t2;
drop table t1,t2,t3;
create table t1 (s1 int);
create view v1 as select * from t1;
handler v1 open as xx;

23
mysql-test/t/help.test
View File

@ -114,4 +114,25 @@ delete from mysql.help_relation where help_keyword_id=@keyword2_id and help_topi
delete from mysql.help_relation where help_keyword_id=@keyword3_id and help_topic_id=@topic3_id;
delete from mysql.help_relation where help_keyword_id=@keyword3_id and help_topic_id=@topic4_id;
# End of 4.1 tests
--echo End of 4.1 tests.
#
# Test that we can use HELP even under LOCK TABLES. See bug#9953:
# CONVERT_TZ requires mysql.time_zone_name to be locked.
#
--disable_warnings
DROP TABLE IF EXISTS t1;
--enable_warnings
CREATE TABLE t1 (i INT);
LOCK TABLES t1 WRITE;
HELP no_such_topic;
UNLOCK TABLES;
DROP TABLE t1;
--echo End of 5.1 tests.

44
mysql-test/t/lock.test
View File

@ -92,7 +92,8 @@ delete from t2 using t1,t2 where t1.a=t2.a;
delete t2 from t1,t2 where t1.a=t2.a;
drop table t1,t2;
# End of 4.1 tests
--echo End of 4.1 tests.
#
# Bug#18884 "lock table + global read lock = crash"
@ -108,3 +109,44 @@ flush tables with read lock;
unlock tables;
drop table t1;
#
# Test LOCK TABLE on system tables. See bug#9953: CONVERT_TZ requires
# mysql.time_zone_name to be locked.
#
--disable_warnings
DROP TABLE IF EXISTS t1;
--enable_warnings
CREATE TABLE t1 (i INT);
LOCK TABLES mysql.time_zone READ, mysql.proc READ, t1 READ;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone READ, mysql.proc READ, t1 WRITE;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone READ, mysql.proc READ;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE;
UNLOCK TABLES;
# If at least one system table is locked for WRITE, then all other
# tables should be system tables locked also for WRITE.
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone READ, mysql.proc WRITE, t1 READ;
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE, t1 READ;
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE, t1 WRITE;
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone READ, mysql.proc WRITE;
DROP TABLE t1;
--echo End of 5.1 tests.

28
mysql-test/t/timezone2.test
View File

@ -246,3 +246,31 @@ drop function f1;
SET GLOBAL log_bin_trust_function_creators = 0;
# End of 5.0 tests
#
# BUG#9953: CONVERT_TZ requires mysql.time_zone_name to be locked
# BUG#19339: CONVERT_TZ(): overly aggressive in locking time_zone_name
# table
#
--disable_warnings
DROP TABLE IF EXISTS t1;
--enable_warnings
CREATE TABLE t1 (t TIMESTAMP);
INSERT INTO t1 VALUES (NULL), (NULL);
LOCK TABLES t1 WRITE;
# The following two queries should not return error that time zone
# tables aren't locked. We use IS NULL below to supress timestamp
# result.
SELECT CONVERT_TZ(NOW(), 'UTC', 'Europe/Moscow') IS NULL;
UPDATE t1 SET t = CONVERT_TZ(t, 'UTC', 'Europe/Moscow');
UNLOCK TABLES;
DROP TABLE t1;
--echo End of 5.1 tests

5
mysql-test/t/view.test
View File

@ -832,6 +832,7 @@ drop table t1;
#
create table t1 (col1 int);
create table t2 (col1 int);
create table t3 (col1 datetime not null);
create view v1 as select * from t1;
create view v2 as select * from v1;
create view v3 as select v2.col1 from v2,t2 where v2.col1 = t2.col1;
@ -938,7 +939,7 @@ insert into v3 (col1) values ((select max(col1) from v2));
insert into v3 (col1) values ((select CONVERT_TZ('20050101000000','UTC','MET') from v2));
insert into v3 (col1) values ((select CONVERT_TZ('20050101000000','UTC','MET') from t2));
-- error 1048
insert into mysql.time_zone values ('', (select CONVERT_TZ('20050101000000','UTC','MET') from t2));
insert into t3 values ((select CONVERT_TZ('20050101000000','UTC','MET') from t2));
# temporary table algorithm view should be equal to subquery in the from clause
create algorithm=temptable view v4 as select * from t1;
insert into t1 values (1),(2),(3);
@ -946,7 +947,7 @@ insert into t1 (col1) values ((select max(col1) from v4));
select * from t1;
drop view v4,v3,v2,v1;
drop table t1,t2;
drop table t1,t2,t3;
#
# HANDLER with VIEW