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Commit 3dd3a5da authored by Vicențiu Ciorbaru's avatar Vicențiu Ciorbaru
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MDEV-9935: Window functions: assertion failure with empty OVER () clause 

Make window functions work with an empty over clause by forcing
a sort on the first column of the current join_tab. This is a temporary
fix until we get window functions to work with big tables.
parent e992464f
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Showing with 237 additions and 3 deletions
mysql-test/r/win_empty_over.result 0 → 100644
View file @ 3dd3a5da
create table t1 (
pk int primary key,
a int,
b int,
c char(10),
d decimal(10, 3),
e real
);
insert into t1 values
( 1, 0, 1, 'one', 0.1, 0.001),
( 2, 0, 2, 'two', 0.2, 0.002),
( 3, 0, 3, 'three', 0.3, 0.003),
( 4, 1, 2, 'three', 0.4, 0.004),
( 5, 1, 1, 'two', 0.5, 0.005),
( 6, 1, 1, 'one', 0.6, 0.006),
( 7, 2, NULL, 'n_one', 0.5, 0.007),
( 8, 2, 1, 'n_two', NULL, 0.008),
( 9, 2, 2, NULL, 0.7, 0.009),
(10, 2, 0, 'n_four', 0.8, 0.010),
(11, 2, 10, NULL, 0.9, NULL);
select pk, row_number() over () from t1;
pk row_number() over ()
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 10
11 11
explain FORMAT=JSON select pk, row_number() over () from t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"window_functions_computation": {
"sorts": {
"filesort": {
"sort_key": "pk"
}
},
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "index",
"key": "PRIMARY",
"key_length": "4",
"used_key_parts": ["pk"],
"rows": 11,
"filtered": 100,
"using_index": true
}
}
}
}
}
explain FORMAT=JSON select row_number() over (), pk from t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"window_functions_computation": {
"sorts": {
"filesort": {
"sort_key": "`row_number() over ()`"
}
},
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "index",
"key": "PRIMARY",
"key_length": "4",
"used_key_parts": ["pk"],
"rows": 11,
"filtered": 100,
"using_index": true
}
}
}
}
}
select row_number() over () from (select 4) as t;
row_number() over ()
1
select min(a) over (), max(a) over (), a, row_number() over ()
from t1
where a = 0;
min(a) over () max(a) over () a row_number() over ()
0 0 0 1
0 0 0 2
0 0 0 3
select a, min(a) over (), max(a) over (), row_number() over ()
from t1
where a = 0;
a min(a) over () max(a) over () row_number() over ()
0 0 0 1
0 0 0 2
0 0 0 3
select min(a) over () + 1, max(a) over (), row_number() over ()
from t1
where a = 0;
min(a) over () + 1 max(a) over () row_number() over ()
1 0 1
1 0 2
1 0 3
select min(a) over () + a, max(a) over (), row_number() over ()
from t1
where a = 1;
min(a) over () + a max(a) over () row_number() over ()
2 1 1
2 1 2
2 1 3
select a + min(a) over (), max(a) over (), row_number() over ()
from t1
where a = 1;
a + min(a) over () max(a) over () row_number() over ()
2 1 1
2 1 2
2 1 3
select a + min(a) over () from t1 where a = 1;
a + min(a) over ()
2
2
2
create view win_view
as (select a, min(a) over () from t1 where a = 1);
select * from win_view;
a min(a) over ()
1 1
1 1
1 1
drop view win_view;
create view win_view
as (select a, max(a + 1) over () from t1 where a = 1);
select * from win_view;
a max(a + 1) over ()
1 3
1 3
1 3
drop view win_view;
drop table t1;
mysql-test/t/win_empty_over.test 0 → 100644
View file @ 3dd3a5da
create table t1 (
pk int primary key,
a int,
b int,
c char(10),
d decimal(10, 3),
e real
);
insert into t1 values
( 1, 0, 1, 'one', 0.1, 0.001),
( 2, 0, 2, 'two', 0.2, 0.002),
( 3, 0, 3, 'three', 0.3, 0.003),
( 4, 1, 2, 'three', 0.4, 0.004),
( 5, 1, 1, 'two', 0.5, 0.005),
( 6, 1, 1, 'one', 0.6, 0.006),
( 7, 2, NULL, 'n_one', 0.5, 0.007),
( 8, 2, 1, 'n_two', NULL, 0.008),
( 9, 2, 2, NULL, 0.7, 0.009),
(10, 2, 0, 'n_four', 0.8, 0.010),
(11, 2, 10, NULL, 0.9, NULL);
select pk, row_number() over () from t1;
explain FORMAT=JSON select pk, row_number() over () from t1;
explain FORMAT=JSON select row_number() over (), pk from t1;
select row_number() over () from (select 4) as t;
--sorted_result
select min(a) over (), max(a) over (), a, row_number() over ()
from t1
where a = 0;
--sorted_result
select a, min(a) over (), max(a) over (), row_number() over ()
from t1
where a = 0;
--sorted_result
select min(a) over () + 1, max(a) over (), row_number() over ()
from t1
where a = 0;
--sorted_result
select min(a) over () + a, max(a) over (), row_number() over ()
from t1
where a = 1;
--sorted_result
select a + min(a) over (), max(a) over (), row_number() over ()
from t1
where a = 1;
select a + min(a) over () from t1 where a = 1;
create view win_view
as (select a, min(a) over () from t1 where a = 1);
select * from win_view;
drop view win_view;
create view win_view
as (select a, max(a + 1) over () from t1 where a = 1);
select * from win_view;
drop view win_view;
drop table t1;
sql/sql_window.cc
View file @ 3dd3a5da
......@@ -2509,7 +2509,8 @@ bool Window_funcs_sort::exec(JOIN *join)
bool Window_funcs_sort::setup(THD *thd, SQL_SELECT *sel,
List_iterator<Item_window_func> &it)
List_iterator<Item_window_func> &it,
JOIN_TAB *join_tab)
{
Window_spec *spec;
Item_window_func *win_func= it.peek();
......@@ -2547,6 +2548,27 @@ bool Window_funcs_sort::setup(THD *thd, SQL_SELECT *sel,
ORDER* sort_order= concat_order_lists(thd->mem_root,
spec->partition_list->first,
spec->order_list->first);
if (sort_order == NULL) // No partition or order by clause.
{
/* TODO(cvicentiu) This is used as a way to allow an empty OVER ()
clause for window functions. However, a better approach is
to not call Filesort at all in this case and just read whatever order
the temporary table has.
Due to cursors not working for out_of_memory cases (yet!), we have to run
filesort to generate a sort buffer of the results.
In this case we sort by the first field of the temporary table.
We should have this field available, even if it is a window_function
field. We don't care of the particular sorting result in this case.
*/
ORDER *order= (ORDER *)alloc_root(thd->mem_root, sizeof(ORDER));
memset(order, 0, sizeof(*order));
Item *item= new (thd->mem_root) Item_field(thd, join_tab->table->field[0]);
order->item= (Item **)alloc_root(thd->mem_root, 2 * sizeof(Item *));
order->item[1]= NULL;
order->item[0]= item;
order->field= join_tab->table->field[0];
sort_order= order;
}
filesort= new (thd->mem_root) Filesort(sort_order, HA_POS_ERROR, true, NULL);
/* Apply the same condition that the subsequent sort has. */
......@@ -2574,7 +2596,7 @@ bool Window_funcs_computation::setup(THD *thd,
while (iter.peek())
{
if (!(srt= new Window_funcs_sort()) ||
srt->setup(thd, sel, iter))
srt->setup(thd, sel, iter, tab))
{
return true;
}
......
sql/sql_window.h
View file @ 3dd3a5da
......@@ -186,7 +186,8 @@ class Window_func_runner : public Sql_alloc
class Window_funcs_sort : public Sql_alloc
{
public:
bool setup(THD *thd, SQL_SELECT *sel, List_iterator<Item_window_func> &it);
bool setup(THD *thd, SQL_SELECT *sel, List_iterator<Item_window_func> &it,
st_join_table *join_tab);
bool exec(JOIN *join);
void cleanup() { delete filesort; }
......
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