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A fix and a test case for Bug#24918 drop table and lock / inconsistent

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between perm and temp tables. Review fixes.

The original bug report complains that if we locked a temporary table
with LOCK TABLES statement, we would not leave LOCK TABLES mode
when this temporary table is dropped.

Additionally, the bug was escalated when it was discovered than
when a temporary transactional table that was previously
locked with LOCK TABLES statement was dropped, futher actions with
this table, such as UNLOCK TABLES, would lead to a crash.

The problem originates from incomplete support of transactional temporary
tables. When we added calls to handler::store_lock()/handler::external_lock()
to operations that work with such tables, we only covered the normal
server code flow and did not cover LOCK TABLES mode. 
In LOCK TABLES mode, ::external_lock(LOCK) would sometimes be called without
matching ::external_lock(UNLOCK), e.g. when a transactional temporary table
was dropped. Additionally, this table would be left in the list of LOCKed 
TABLES.

The patch aims to address this inadequacy. Now, whenever an instance
of 'handler' is destroyed, we assert that it was priorly
external_lock(UNLOCK)-ed. All the places that violate this assert
were fixed.

This patch introduces no changes in behavior -- the discrepancy in
behavior will be fixed when we start calling ::store_lock()/::external_lock()
for all tables, regardless whether they are transactional or not, 
temporary or not.
This commit is contained in:
kostja@bodhi.(none)
2007-07-27 16:37:29 +04:00
parent 9f8593e81c
commit 11c57540f7
9 changed files with 192 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
mysql-test/t/innodb_mysql.test
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@ -754,4 +754,38 @@ create table t1 (a int) engine=innodb;
alter table t1 alter a set default 1;
drop table t1;
--echo
--echo Bug#24918 drop table and lock / inconsistent between
--echo perm and temp tables
--echo
--echo Check transactional tables under LOCK TABLES
--echo
--disable_warnings
drop table if exists t24918, t24918_tmp, t24918_trans, t24918_trans_tmp,
t24918_access;
--enable_warnings
create table t24918_access (id int);
create table t24918 (id int) engine=myisam;
create temporary table t24918_tmp (id int) engine=myisam;
create table t24918_trans (id int) engine=innodb;
create temporary table t24918_trans_tmp (id int) engine=innodb;
lock table t24918 write, t24918_tmp write, t24918_trans write, t24918_trans_tmp write;
drop table t24918;
--error ER_TABLE_NOT_LOCKED
select * from t24918_access;
drop table t24918_trans;
--error ER_TABLE_NOT_LOCKED
select * from t24918_access;
drop table t24918_trans_tmp;
--error ER_TABLE_NOT_LOCKED
select * from t24918_access;
drop table t24918_tmp;
--error ER_TABLE_NOT_LOCKED
select * from t24918_access;
unlock tables;
drop table t24918_access;
--echo End of 5.0 tests