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MDEV-34506 2nd execution name resolution problem with pushdown into unions

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Statements affected by this bug need all the following to be true
1) a derived table table or view whose specification contains a set
     operation at the top level.
2) a grouping operator (group by/having) operating on a column alias
     other than in the first select of the union/intersect
3) an outer condition that will be pushed into all selects in this
     union/intersect, either into the where or having clause

When pushing a condition into all selects of a unit with more than one
select, pushdown_cond_for_derived() renames items so we can re-use the
condition being pushed.
These names need to be saved and reset for correct name resolution on
second execution of prepared statements.

Reviewed by Igor Babaev (igor@mariadb.com)
This commit is contained in:
Rex 2024-07-02 12:27:41 +11:00
parent 7e5c9ccda5
commit 48b256a7e2
3 changed files with 583 additions and 0 deletions
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495
mysql-test/main/derived_cond_pushdown.result
View File

@ -18557,3 +18557,498 @@ valdouble valint1
5 3289988
DROP TABLE t1,t2;
# End of 10.4 tests
# MDEV-34506 2nd execution name resolution problem with pushdown into
# unions
#
# Statements affected by this bug need all the following to be true
# 1) a derived table table or view whose specification contains a set
# operation at the top level.
# 2) a grouping operator (group by/having) operating on a column alias
# other than in the first select of the union/intersect
# 3) an outer condition that will be pushed into all selects in this
# union/intersect, either into the where or having clause
#
# When pushing a condition into all selects of a unit with more than one
# select, pushdown_cond_for_derived() renames items so we can re-use the
# condition being pushed.
# These names need to be saved and reset for correct name resolution on
# second execution of prepared statements.
create table t1 (c1 int, c2 int, c3 int);
insert into t1 values (1,2,3),(1,2,2),(4,5,6);
insert into t1 values (17,8,9),(11,11,12);
create table t2 (c4 int, c5 int, c6 int);
insert into t2 values (7,8,9),(10,11,12);
prepare stmt from 'select * from
(
select c1, sum(c3) as s from t1 group by c1
union
select c4 as c, sum(c6) as u from t2 group by c
) dt
where c1 > 6';
execute stmt;
c1 s
11 12
17 9
7 9
10 12
execute stmt;
c1 s
11 12
17 9
7 9
10 12
prepare stmt from 'explain format=json select * from
(
select c1, sum(c3) as s from t1 group by c1
union
select c4 as c, sum(c6) as u from t2 group by c
) dt
where c1 > 6';
execute stmt;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "<derived2>",
"access_type": "ALL",
"rows": 7,
"filtered": 100,
"attached_condition": "dt.c1 > 6",
"materialized": {
"query_block": {
"union_result": {
"table_name": "<union2,3>",
"access_type": "ALL",
"query_specifications": [
{
"query_block": {
"select_id": 2,
"filesort": {
"sort_key": "t1.c1",
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows": 5,
"filtered": 100,
"attached_condition": "t1.c1 > 6"
}
}
}
}
},
{
"query_block": {
"select_id": 3,
"operation": "UNION",
"filesort": {
"sort_key": "t2.c4",
"temporary_table": {
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100,
"attached_condition": "t2.c4 > 6"
}
}
}
}
}
]
}
}
}
}
}
}
execute stmt;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "<derived2>",
"access_type": "ALL",
"rows": 7,
"filtered": 100,
"attached_condition": "dt.c1 > 6",
"materialized": {
"query_block": {
"union_result": {
"table_name": "<union2,3>",
"access_type": "ALL",
"query_specifications": [
{
"query_block": {
"select_id": 2,
"filesort": {
"sort_key": "t1.c1",
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows": 5,
"filtered": 100,
"attached_condition": "t1.c1 > 6"
}
}
}
}
},
{
"query_block": {
"select_id": 3,
"operation": "UNION",
"filesort": {
"sort_key": "t2.c4",
"temporary_table": {
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100,
"attached_condition": "t2.c4 > 6"
}
}
}
}
}
]
}
}
}
}
}
}
prepare stmt from 'select * from
(
select c1, c2, sum(c3) as s from t1 group by c1, c2 having s > 2
union
select c4, c5, sum(c6) as u from t2 group by c4, c5 having u > 3
) dt
where c2 > 5';
execute stmt;
c1 c2 s
11 11 12
17 8 9
7 8 9
10 11 12
execute stmt;
c1 c2 s
11 11 12
17 8 9
7 8 9
10 11 12
prepare stmt from 'explain format=json select * from
(
select c1, c2, sum(c3) as s from t1 group by c1, c2 having s > 2
union
select c4, c5, sum(c6) as u from t2 group by c4, c5 having u > 3
) dt
where c2 > 5';
execute stmt;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "<derived2>",
"access_type": "ALL",
"rows": 7,
"filtered": 100,
"attached_condition": "dt.c2 > 5",
"materialized": {
"query_block": {
"union_result": {
"table_name": "<union2,3>",
"access_type": "ALL",
"query_specifications": [
{
"query_block": {
"select_id": 2,
"having_condition": "s > 2",
"filesort": {
"sort_key": "t1.c1, t1.c2",
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows": 5,
"filtered": 100,
"attached_condition": "t1.c2 > 5"
}
}
}
}
},
{
"query_block": {
"select_id": 3,
"operation": "UNION",
"having_condition": "s > 3",
"filesort": {
"sort_key": "t2.c4, t2.c5",
"temporary_table": {
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100,
"attached_condition": "t2.c5 > 5"
}
}
}
}
}
]
}
}
}
}
}
}
execute stmt;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "<derived2>",
"access_type": "ALL",
"rows": 7,
"filtered": 100,
"attached_condition": "dt.c2 > 5",
"materialized": {
"query_block": {
"union_result": {
"table_name": "<union2,3>",
"access_type": "ALL",
"query_specifications": [
{
"query_block": {
"select_id": 2,
"having_condition": "s > 2",
"filesort": {
"sort_key": "t1.c1, t1.c2",
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows": 5,
"filtered": 100,
"attached_condition": "t1.c2 > 5"
}
}
}
}
},
{
"query_block": {
"select_id": 3,
"operation": "UNION",
"having_condition": "s > 3",
"filesort": {
"sort_key": "t2.c4, t2.c5",
"temporary_table": {
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100,
"attached_condition": "t2.c5 > 5"
}
}
}
}
}
]
}
}
}
}
}
}
prepare stmt from 'select *
from
(
select c1, c2, max(c3) as max_c, avg(c3) as avg_c
from t1
group by c1,c2
having max_c < 7
union
select c4, c5, max(c6) as u, avg(c6) as w
from t2
group by c4, c5
having u < 10
) dt,
t2
where dt.max_c > 6 and t2.c6 > dt.c1';
execute stmt;
c1 c2 max_c avg_c c4 c5 c6
7 8 9 9.0000 7 8 9
7 8 9 9.0000 10 11 12
execute stmt;
c1 c2 max_c avg_c c4 c5 c6
7 8 9 9.0000 7 8 9
7 8 9 9.0000 10 11 12
prepare stmt from 'explain format=json select *
from
(
select c1, c2, max(c3) as max_c, avg(c3) as avg_c
from t1
group by c1,c2
having max_c < 7
union
select c4, c5, max(c6) as u, avg(c6) as w
from t2
group by c4, c5
having u < 10
) dt,
t2
where dt.max_c > 6 and t2.c6 > dt.c1';
execute stmt;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100
},
"block-nl-join": {
"table": {
"table_name": "<derived2>",
"access_type": "ALL",
"rows": 7,
"filtered": 100,
"attached_condition": "dt.max_c > 6"
},
"buffer_type": "flat",
"buffer_size": "173",
"join_type": "BNL",
"attached_condition": "t2.c6 > dt.c1",
"materialized": {
"query_block": {
"union_result": {
"table_name": "<union2,3>",
"access_type": "ALL",
"query_specifications": [
{
"query_block": {
"select_id": 2,
"having_condition": "max_c < 7 and max_c > 6",
"filesort": {
"sort_key": "t1.c1, t1.c2",
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows": 5,
"filtered": 100
}
}
}
}
},
{
"query_block": {
"select_id": 3,
"operation": "UNION",
"having_condition": "max_c < 10 and max_c > 6",
"filesort": {
"sort_key": "t2.c4, t2.c5",
"temporary_table": {
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100
}
}
}
}
}
]
}
}
}
}
}
}
execute stmt;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100
},
"block-nl-join": {
"table": {
"table_name": "<derived2>",
"access_type": "ALL",
"rows": 7,
"filtered": 100,
"attached_condition": "dt.max_c > 6"
},
"buffer_type": "flat",
"buffer_size": "173",
"join_type": "BNL",
"attached_condition": "t2.c6 > dt.c1",
"materialized": {
"query_block": {
"union_result": {
"table_name": "<union2,3>",
"access_type": "ALL",
"query_specifications": [
{
"query_block": {
"select_id": 2,
"having_condition": "max_c < 7 and max_c > 6",
"filesort": {
"sort_key": "t1.c1, t1.c2",
"temporary_table": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows": 5,
"filtered": 100
}
}
}
}
},
{
"query_block": {
"select_id": 3,
"operation": "UNION",
"having_condition": "max_c < 10 and max_c > 6",
"filesort": {
"sort_key": "t2.c4, t2.c5",
"temporary_table": {
"table": {
"table_name": "t2",
"access_type": "ALL",
"rows": 2,
"filtered": 100
}
}
}
}
}
]
}
}
}
}
}
}
drop table t1, t2;
# End of 10.5 tests

87
mysql-test/main/derived_cond_pushdown.test
View File

@ -4102,3 +4102,90 @@ eval $q;
DROP TABLE t1,t2;
--echo # End of 10.4 tests
--echo # MDEV-34506 2nd execution name resolution problem with pushdown into
--echo # unions
--echo #
--echo # Statements affected by this bug need all the following to be true
--echo # 1) a derived table table or view whose specification contains a set
--echo # operation at the top level.
--echo # 2) a grouping operator (group by/having) operating on a column alias
--echo # other than in the first select of the union/intersect
--echo # 3) an outer condition that will be pushed into all selects in this
--echo # union/intersect, either into the where or having clause
--echo #
--echo # When pushing a condition into all selects of a unit with more than one
--echo # select, pushdown_cond_for_derived() renames items so we can re-use the
--echo # condition being pushed.
--echo # These names need to be saved and reset for correct name resolution on
--echo # second execution of prepared statements.
create table t1 (c1 int, c2 int, c3 int);
insert into t1 values (1,2,3),(1,2,2),(4,5,6);
insert into t1 values (17,8,9),(11,11,12);
create table t2 (c4 int, c5 int, c6 int);
insert into t2 values (7,8,9),(10,11,12);
let $q=select * from
(
select c1, sum(c3) as s from t1 group by c1
union
select c4 as c, sum(c6) as u from t2 group by c
) dt
where c1 > 6;
eval prepare stmt from '$q';
execute stmt;
execute stmt;
eval prepare stmt from 'explain format=json $q';
--source include/analyze-format.inc
execute stmt;
--source include/analyze-format.inc
execute stmt;
let $q=select * from
(
select c1, c2, sum(c3) as s from t1 group by c1, c2 having s > 2
union
select c4, c5, sum(c6) as u from t2 group by c4, c5 having u > 3
) dt
where c2 > 5;
eval prepare stmt from '$q';
execute stmt;
execute stmt;
eval prepare stmt from 'explain format=json $q';
--source include/analyze-format.inc
execute stmt;
--source include/analyze-format.inc
execute stmt;
let $q=select *
from
(
select c1, c2, max(c3) as max_c, avg(c3) as avg_c
from t1
group by c1,c2
having max_c < 7
union
select c4, c5, max(c6) as u, avg(c6) as w
from t2
group by c4, c5
having u < 10
) dt,
t2
where dt.max_c > 6 and t2.c6 > dt.c1;
eval prepare stmt from '$q';
execute stmt;
execute stmt;
eval prepare stmt from 'explain format=json $q';
--source include/analyze-format.inc
execute stmt;
--source include/analyze-format.inc
execute stmt;
drop table t1, t2;
--echo # End of 10.5 tests

1
sql/sql_derived.cc
View File

@ -1557,6 +1557,7 @@ bool pushdown_cond_for_derived(THD *thd, Item *cond, TABLE_LIST *derived)
if (sl != first_sl)
{
DBUG_ASSERT(sl->item_list.elements == first_sl->item_list.elements);
sl->save_item_list_names(thd);
List_iterator_fast<Item> it(sl->item_list);
List_iterator_fast<Item> nm_it(unit->types);
while (Item *item= it++)