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MDEV-13774: Server Crash on Execute of SQL Statement
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Window functions can not be used as arguments to aggregate functions, as
the aggregation happens before window function computation. Disallow
such constructs by returning an error.

In order to detect this case a change was needed in the base
Item_sum_xxx::fix_fields to propagate the with_window_func flag.

Item_func_group_concat requires the same change.
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@cvicentiu
cvicentiu committed Sep 19, 2017
1 parent 3320935 commit 454b9b1
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Showing 4 changed files with 277 additions and 2 deletions.
114 changes: 114 additions & 0 deletions mysql-test/r/win_as_arg_to_aggregate_func.result
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create table t1 (i int);
insert into t1 values (5),(6),(0);
#
# Try out all set functions with window functions as arguments.
# Any such usage should return an error.
#
select MIN( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select MIN(DISTINCT SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select MAX( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select MAX(DISTINCT SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select SUM( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select SUM(DISTINCT SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select AVG( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select AVG(DISTINCT SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select COUNT( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select COUNT(DISTINCT SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select BIT_AND( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select BIT_OR( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select BIT_XOR( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select STD( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select STDDEV( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select STDDEV_POP( SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select STDDEV_SAMP(SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select VARIANCE(SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select VAR_POP(SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select VAR_SAMP(SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select GROUP_CONCAT(SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
select GROUP_CONCAT(DISTINCT SUM(i) OVER (order by i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
#
# Test that partition instead of order by in over doesn't change result.
#
select SUM( SUM(i) OVER (PARTITION BY i) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
#
# Test that no arguments in OVER() clause lead to crash in this case.
#
select SUM( SUM(i) OVER () )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
drop table t1;
#
# MDEV-13774: Server Crash on Execuate of SQL Statement
#
create table t1 (i int);
insert into t1 values (5),(6),(0);
select SUM(
IF( SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0
AND
SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0,
1,
0) )
from t1;
ERROR HY000: Window functions can not be used as arguments to group functions.
#
# A way to get the aggregation result.
#
select i, IF(SUM(IF(i,1,0)) OVER (PARTITION BY i) > 0 AND SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0,1,0) AS if_col
from t1
order by i;
i if_col
0 0
5 1
6 1
select sum(if_col)
from (select IF(SUM(IF(i,1,0)) OVER (PARTITION BY i) > 0 AND SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0,1,0) AS if_col
from t1) tmp;
sum(if_col)
2
drop table t1;
139 changes: 139 additions & 0 deletions mysql-test/t/win_as_arg_to_aggregate_func.test
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create table t1 (i int);
insert into t1 values (5),(6),(0);

--echo #
--echo # Try out all set functions with window functions as arguments.
--echo # Any such usage should return an error.
--echo #
--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select MIN( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select MIN(DISTINCT SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select MAX( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select MAX(DISTINCT SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select SUM( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select SUM(DISTINCT SUM(i) OVER (order by i) )
from t1;


--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select AVG( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select AVG(DISTINCT SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select COUNT( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select COUNT(DISTINCT SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select BIT_AND( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select BIT_OR( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select BIT_XOR( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select STD( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select STDDEV( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select STDDEV_POP( SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select STDDEV_SAMP(SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select VARIANCE(SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select VAR_POP(SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select VAR_SAMP(SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select GROUP_CONCAT(SUM(i) OVER (order by i) )
from t1;

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select GROUP_CONCAT(DISTINCT SUM(i) OVER (order by i) )
from t1;

--echo #
--echo # Test that partition instead of order by in over doesn't change result.
--echo #

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select SUM( SUM(i) OVER (PARTITION BY i) )
from t1;

--echo #
--echo # Test that no arguments in OVER() clause lead to crash in this case.
--echo #
--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select SUM( SUM(i) OVER () )
from t1;
drop table t1;

-- echo #
-- echo # MDEV-13774: Server Crash on Execuate of SQL Statement
-- echo #
create table t1 (i int);
insert into t1 values (5),(6),(0);

--error ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
select SUM(
IF( SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0
AND
SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0,
1,
0) )
from t1;

--echo #
--echo # A way to get the aggregation result.
--echo #

select i, IF(SUM(IF(i,1,0)) OVER (PARTITION BY i) > 0 AND SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0,1,0) AS if_col
from t1
order by i;

select sum(if_col)
from (select IF(SUM(IF(i,1,0)) OVER (PARTITION BY i) > 0 AND SUM( IF(i,1,0)) OVER (PARTITION BY i) > 0,1,0) AS if_col
from t1) tmp;
drop table t1;
23 changes: 22 additions & 1 deletion sql/item_sum.cc
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Expand Up @@ -100,7 +100,11 @@ bool Item_sum::init_sum_func_check(THD *thd)
The method verifies whether context conditions imposed on a usage
of any set function are met for this occurrence.
It checks whether the set function occurs in the position where it
The function first checks if we are using any window functions as
arguments to the set function. In that case it returns an error.
Afterwards, it checks whether the set function occurs in the position where it
can be aggregated and, when it happens to occur in argument of another
set function, the method checks that these two functions are aggregated in
different subqueries.
Expand Down Expand Up @@ -151,6 +155,20 @@ bool Item_sum::check_sum_func(THD *thd, Item **ref)
curr_sel->name_visibility_map);
bool invalid= FALSE;
DBUG_ASSERT(curr_sel->name_visibility_map); // should be set already

/*
Window functions can not be used as arguments to sum functions.
Aggregation happes before window function computation, so there
are no values to aggregate over.
*/
if (with_window_func)
{
my_message(ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG,
ER_THD(thd, ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG),
MYF(0));
return TRUE;
}

if (window_func_sum_expr_flag)
return false;
/*
Expand Down Expand Up @@ -1108,6 +1126,7 @@ Item_sum_num::fix_fields(THD *thd, Item **ref)
return TRUE;
set_if_bigger(decimals, args[i]->decimals);
with_subselect|= args[i]->with_subselect;
with_window_func|= args[i]->with_window_func;
}
result_field=0;
max_length=float_length(decimals);
Expand Down Expand Up @@ -1139,6 +1158,7 @@ Item_sum_hybrid::fix_fields(THD *thd, Item **ref)
return TRUE;
Type_std_attributes::set(args[0]);
with_subselect= args[0]->with_subselect;
with_window_func|= args[0]->with_window_func;

Item *item2= item->real_item();
if (item2->type() == Item::FIELD_ITEM)
Expand Down Expand Up @@ -3480,6 +3500,7 @@ Item_func_group_concat::fix_fields(THD *thd, Item **ref)
args[i]->check_cols(1))
return TRUE;
with_subselect|= args[i]->with_subselect;
with_window_func|= args[i]->with_window_func;
}

/* skip charset aggregation for order columns */
Expand Down
3 changes: 2 additions & 1 deletion sql/share/errmsg-utf8.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -7740,4 +7740,5 @@ ER_RDB_TTL_DURATION_FORMAT
ER_PER_INDEX_CF_DEPRECATED
eng "The per-index column family option has been deprecated"


ER_SUM_FUNC_WITH_WINDOW_FUNC_AS_ARG
eng "Window functions can not be used as arguments to group functions."

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