database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

MDEV-24919 Crash with subselect formed by table value constructor and

Browse Source 
used in set function

If a subselect is formed by a table value constructor (TVC) then the
following transformation is applied at the prepare stage:
  VALUES (v1), ... (vn) => SELECT * FROM (VALUES (v1), ... (vn)) tvc_x.
The transformation is performed by the function wrap_tvc() that resets
THD::LEX::current select to the top level select of the result of the
transformation. After the call of wrap_tvc() in the function
Item_subselect::wrap_tvc_into_select() the field THD::LEX::current must be
reset to the same select as before the call. It was not done. As a result
if the subselect formed by a TVC was an argument of a set function then
an assertion was hit in the function Item_sum::check_sum_func().

Approved by Oleksandr Byelkin <sanja@mariadb.com>
This commit is contained in:
Igor Babaev
2021-03-01 09:40:33 -08:00
parent c25e6f91da
commit 0f81ca6a0b
3 changed files with 17 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
mysql-test/main/table_value_constr.result
View File

@ -2881,4 +2881,10 @@ NULL
deallocate prepare stmt;
drop view v1;
drop table t1,t2,t3;
#
# MDEV-24919: subselect formed by TVC and used in set function
#
select sum((values(1)));
sum((values(1)))
1
End of 10.3 tests

6
mysql-test/main/table_value_constr.test
View File

@ -1516,4 +1516,10 @@ deallocate prepare stmt;
drop view v1;
drop table t1,t2,t3;
--echo #
--echo # MDEV-24919: subselect formed by TVC and used in set function
--echo #
select sum((values(1)));
--echo End of 10.3 tests

13
sql/sql_tvc.cc
View File

@ -648,7 +648,7 @@ st_select_lex *wrap_tvc(THD *thd, st_select_lex *tvc_sl,
st_select_lex *parent_select)
{
LEX *lex= thd->lex;
select_result *save_result= thd->lex->result;
select_result *save_result= lex->result;
uint8 save_derived_tables= lex->derived_tables;
thd->lex->result= NULL;
@ -729,13 +729,13 @@ st_select_lex *wrap_tvc(THD *thd, st_select_lex *tvc_sl,
if (arena)
thd->restore_active_arena(arena, &backup);
thd->lex->result= save_result;
lex->result= save_result;
return wrapper_sl;
err:
if (arena)
thd->restore_active_arena(arena, &backup);
thd->lex->result= save_result;
lex->result= save_result;
lex->derived_tables= save_derived_tables;
return 0;
}
@ -819,14 +819,9 @@ Item_subselect::wrap_tvc_into_select(THD *thd, st_select_lex *tvc_sl)
{
if (engine->engine_type() == subselect_engine::SINGLE_SELECT_ENGINE)
((subselect_single_select_engine *) engine)->change_select(wrapper_sl);
lex->current_select= wrapper_sl;
return wrapper_sl;
}
else
{
lex->current_select= parent_select;
return 0;
}
return wrapper_sl;
}