Bug#54678: InnoDB, TRUNCATE, ALTER, I_S SELECT, crash or deadlock
- Incompatible change: truncate no longer resorts to a row by
row delete if the storage engine does not support the truncate
method. Consequently, the count of affected rows does not, in
any case, reflect the actual number of rows.
- Incompatible change: it is no longer possible to truncate a
table that participates as a parent in a foreign key constraint,
unless it is a self-referencing constraint (both parent and child
are in the same table). To work around this incompatible change
and still be able to truncate such tables, disable foreign checks
with SET foreign_key_checks=0 before truncate. Alternatively, if
foreign key checks are necessary, please use a DELETE statement
without a WHERE condition.
Problem description:
The problem was that for storage engines that do not support
truncate table via a external drop and recreate, such as InnoDB
which implements truncate via a internal drop and recreate, the
delete_all_rows method could be invoked with a shared metadata
lock, causing problems if the engine needed exclusive access
to some internal metadata. This problem originated with the
fact that there is no truncate specific handler method, which
ended up leading to a abuse of the delete_all_rows method that
is primarily used for delete operations without a condition.
Solution:
The solution is to introduce a truncate handler method that is
invoked when the engine does not support truncation via a table
drop and recreate. This method is invoked under a exclusive
metadata lock, so that there is only a single instance of the
table when the method is invoked.
Also, the method is not invoked and a error is thrown if
the table is a parent in a non-self-referencing foreign key
relationship. This was necessary to avoid inconsistency as
some integrity checks are bypassed. This is inline with the
fact that truncate is primarily a DDL operation that was
designed to quickly remove all data from a table.
innodb.innodb [ fail ]
Test ended at 2010-06-02 15:04:06
CURRENT_TEST: innodb.innodb
--- /usr/w/mysql-trunk-innodb/mysql-test/suite/innodb/r/innodb.result 2010-05-23 23:10:26.576407000 +0300
+++ /usr/w/mysql-trunk-innodb/mysql-test/suite/innodb/r/innodb.reject 2010-06-02 15:04:05.000000000 +0300
@@ -2648,7 +2648,7 @@
create table t4 (s1 char(2) binary,primary key (s1)) engine=innodb;
insert into t1 values (0x41),(0x4120),(0x4100);
insert into t2 values (0x41),(0x4120),(0x4100);
-ERROR 23000: Duplicate entry 'A\x00' for key 'PRIMARY'
+ERROR 23000: Duplicate entry 'A' for key 'PRIMARY'
insert into t2 values (0x41),(0x4120);
The change in the printout was introduced in:
------------------------------------------------------------
revno: 3008.6.2
revision-id: sergey.glukhov@sun.com-20100527160143-57nas8nplzpj26dz
parent: sergey.glukhov@sun.com-20100527155443-24vqi9o8rpnkyci7
committer: Sergey Glukhov <Sergey.Glukhov@sun.com>
branch nick: mysql-trunk-bugfixing
timestamp: Thu 2010-05-27 20:01:43 +0400
message:
Bug#52430 Incorrect key in the error message for duplicate key error involving BINARY type
For BINARY(N) strip trailing zeroes to make the error message nice-looking
@ mysql-test/r/errors.result
test case
@ mysql-test/r/type_binary.result
result fix
@ mysql-test/t/errors.test
test case
@ sql/key.cc
For BINARY(N) strip trailing zeroes to make the error message nice-looking
and its author (Sergey) did not notice the test failure because that test
has been disabled in his tree.
Support returning 512 and 511 pages for the buffer pool size, this
is undeterministic and probably depends on alignment issues.
The default buffer pool size is 8M (512) pages, which is set in
include/default_mysqld.cnf. So the previous "replace_result 8192 8191"
had no effect.
Extract part of innodb.innodb into innodb.innodb_misc1
This is needed in order to be able to more easily debug this test,
under valgrind, it is too huge.
