diff options
| author | Sergey Glukhov <sergey.glukhov@oracle.com> | 2011-10-05 13:28:20 +0400 |
|---|---|---|
| committer | Sergey Glukhov <sergey.glukhov@oracle.com> | 2011-10-05 13:28:20 +0400 |
| commit | 14dc91ff83001809fc40380ab22fc4e606f611de (patch) | |
| tree | 27192e80c7e7886d1587e695346110e3cec09e9f /sql/item_subselect.h | |
| parent | 96c2c18e4f6b484aea7cbce5646c1280661f73a9 (diff) | |
| download | mariadb-git-14dc91ff83001809fc40380ab22fc4e606f611de.tar.gz | |
Bug#11747970 34660: CRASH WHEN FEDERATED TABLE LOSES CONNECTION DURING INSERT ... SELECT
Problematic query:
insert ignore into `t1_federated` (`c1`) select `c1` from `t1_local` a
where not exists (select 1 from `t1_federated` b where a.c1 = b.c1);
When this query is killed in another connection it could lead to crash.
The problem is follwing:
An attempt to obtain table statistics for subselect table in killed query
fails with an error. So JOIN::optimize() for subquery is failed but
it does not prevent further subquery evaluation.
At the first subquery execution JOIN::optimize() is called
(see subselect_single_select_engine::exec()) and fails with
an error. 'executed' flag is set to TRUE and it prevents
further subquery evaluation. At the second call
JOIN::optimize() does not happen as 'JOIN::optimized' is TRUE
and in case of uncacheable subquery the 'executed' flag is set
to FALSE before subquery evaluation. So we loose 'optimize stage'
error indication (see subselect_single_select_engine::exec()).
In other words 'executed' flag is used for two purposes, for
error indication at JOIN::optimize() stage and for an
indication of subquery execution. And it seems it's wrong
as the flag could be reset.
mysql-test/r/error_simulation.result:
test case
mysql-test/t/error_simulation.test:
test case
sql/item_subselect.cc:
added new flag subselect_single_select_engine::optimize_error
which is used for error detection which could happen at optimize
stage.
sql/item_subselect.h:
added new flag subselect_single_select_engine::optimize_error
sql/sql_select.cc:
test case
Diffstat (limited to 'sql/item_subselect.h')
| -rw-r--r-- | sql/item_subselect.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/sql/item_subselect.h b/sql/item_subselect.h index 74bbec626c1..65b415b44e9 100644 --- a/sql/item_subselect.h +++ b/sql/item_subselect.h @@ -419,6 +419,7 @@ class subselect_single_select_engine: public subselect_engine my_bool prepared; /* simple subselect is prepared */ my_bool optimized; /* simple subselect is optimized */ my_bool executed; /* simple subselect is executed */ + my_bool optimize_error; ///< simple subselect optimization failed st_select_lex *select_lex; /* corresponding select_lex */ JOIN * join; /* corresponding JOIN structure */ public: |