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MDEV-27510 Query returns wrong result when using split optimization

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This bug may affect the queries that uses a grouping derived table with
grouping list containing references to columns from different tables if
the optimizer decides to employ the split optimization for the derived
table. In some very specific cases it may affect queries with a grouping
derived table that refers only one base table.
This bug was caused by an improper fix for the bug MDEV-25128. The fix
tried to get rid of the equality conditions pushed into the where clause
of the grouping derived table T to which the split optimization had been
applied. The fix erroneously assumed that only those pushed equalities
that were used for ref access of the tables referenced by T were needed.
In fact the function remove_const() that figures out what columns from the
group list can be removed if the split optimization is applied can uses
other pushed equalities as well.
This patch actually provides a proper fix for MDEV-25128. Rather than
trying to remove invalid pushed equalities referencing the fields of SJM
tables with a look-up access the patch attempts not to push such equalities.

Approved by Oleksandr Byelkin <sanja@mariadb.com>
This commit is contained in:
Igor Babaev 2022-01-24 23:14:46 -08:00
parent da37bfd8d6
commit 0041265671
5 changed files with 635 additions and 29 deletions
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439
mysql-test/main/derived_cond_pushdown.result
View file

@ -17439,7 +17439,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <subquery3> eq_ref distinct_key distinct_key 4 func 1
1 PRIMARY <derived2> ref key0 key0 5 test.t3.id 2
3 MATERIALIZED t2 ALL NULL NULL NULL NULL 3
2 LATERAL DERIVED cp2 ref a a 5 test.t1.a 1 Using index
2 LATERAL DERIVED cp2 ref a a 5 test.t1.a 1 Using where; Using index
explain format=json select * from t1, (select a from t1 cp2 group by a) dt, t3
where dt.a = t1.a and t1.a = t3.id and t1.a in (select a from t2);
EXPLAIN
@ -17512,6 +17512,7 @@ EXPLAIN
"ref": ["test.t1.a"],
"rows": 1,
"filtered": 100,
"attached_condition": "cp2.a = t3.`id`",
"using_index": true
}
}
@ -17683,7 +17684,7 @@ EXPLAIN
"ref": ["test.t1.id"],
"rows": 3,
"filtered": 100,
"index_condition": "t2.t1_id between 200 and 100000",
"index_condition": "t2.t1_id between 200 and 100000 and t2.t1_id = t3.t1_id",
"attached_condition": "t2.reporting_person = 1"
}
}
@ -17702,4 +17703,438 @@ WHERE t1.id BETWEEN 200 AND 100000;
id
set optimizer_switch='split_materialized=default';
DROP TABLE t1,t2,t3;
#
# MDEV-27510: Splittable derived with grouping over two tables
#
CREATE TABLE ledgers (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(32)
) ENGINE=MyISAM;
CREATE TABLE charges (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
from_ledger_id BIGINT UNSIGNED NOT NULL,
to_ledger_id BIGINT UNSIGNED NOT NULL,
amount INT NOT NULL,
KEY fk_charge_from_ledger (from_ledger_id),
KEY fk_charge_to_ledger (to_ledger_id)
) ENGINE=MyISAM;
CREATE TABLE transactions (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
ledger_id BIGINT UNSIGNED NOT NULL,
KEY fk_transactions_ledger (ledger_id)
) ENGINE=MyISAM;
CREATE TABLE transaction_items (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
transaction_id BIGINT UNSIGNED NOT NULL,
charge_id BIGINT UNSIGNED,
amount INT NOT NULL,
KEY fk_items_transaction (transaction_id),
KEY fk_items_charge (charge_id)
) ENGINE=MyISAM;
INSERT INTO ledgers (id, name) VALUES
(1, 'Anna'), (2, 'John'), (3, 'Fred');
INSERT INTO charges (id, from_ledger_id, to_ledger_id, amount) VALUES
(1, 2, 1, 200), (2, 1, 2, 330), (3, 1, 2, 640), (4, 3, 1, 640), (5, 3, 2, 1000),
(6, 3, 1, 660), (7, 2, 3, 650), (8, 3, 2, 160), (9, 2, 1, 740), (10, 3, 2, 310),
(11, 2, 1, 640), (12, 3, 2, 240), (13, 3, 2, 340), (14, 2, 1, 720),
(15, 2, 3, 100),
(16, 2, 3, 980), (17, 2, 1, 80), (18, 1, 2, 760), (19, 2, 3, 740),
(20, 2, 1, 990);
INSERT INTO transactions (id, ledger_id) VALUES
(2, 1), (3, 1), (5, 1), (8, 1), (12, 1), (18, 1), (22, 1), (28, 1),
(34, 1), (35, 1),
(40, 1), (1, 2), (4, 2), (6, 2), (10, 2), (13, 2), (16, 2), (17, 2),
(20, 2), (21, 2),
(24, 2), (26, 2), (27, 2), (29, 2), (31, 2), (33, 2), (36, 2), (37, 2),
(39, 2), (7, 3),
(9, 3), (11, 3), (14, 3), (15, 3), (19, 3), (23, 3), (25, 3), (30, 3),
(32, 3), (38, 3);
INSERT INTO transaction_items (id, transaction_id, charge_id, amount) VALUES
(1, 1, 1, -200), (2, 2, 1, 200), (3, 3, 2, -330), (4, 4, 2, 330),
(5, 5, 3, -640),
(6, 6, 3, 640), (7, 7, 4, -640), (8, 8, 4, 640), (9, 9, 5, -1000),
(10, 10, 5, 1000),
(11, 11, 6, -660), (12, 12, 6, 660), (13, 13, 7, -650), (14, 14, 7, 650),
(15, 15, 8, -160),
(16, 16, 8, 160), (17, 17, 9, -740), (18, 18, 9, 740), (19, 19, 10, -310),
(20, 20, 10, 310),
(21, 21, 11, -640), (22, 22, 11, 640), (23, 23, 12, -240), (24, 24, 12, 240),
(25, 25, 13, -340),
(26, 26, 13, 340), (27, 27, 14, -720), (28, 28, 14, 720), (29, 29, 15, -100),
(30, 30, 15, 100),
(31, 31, 16, -980), (32, 32, 16, 980), (33, 33, 17, -80), (34, 34, 17, 80),
(35, 35, 18, -760),
(36, 36, 18, 760), (37, 37, 19, -740), (38, 38, 19, 740), (39, 39, 20, -990),
(40, 40, 20, 990);
ANALYZE TABLE ledgers, charges, transactions, transaction_items;
Table Op Msg_type Msg_text
test.ledgers analyze status OK
test.charges analyze status OK
test.transactions analyze status OK
test.transaction_items analyze status OK
set optimizer_switch='split_materialized=on';
SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
INNER JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id from_ledger_id to_ledger_id from_num_rows
2 1 2 1
3 1 2 1
5 3 2 1
8 3 2 1
10 3 2 1
12 3 2 1
13 3 2 1
18 1 2 1
EXPLAIN SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
INNER JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY charges ref PRIMARY,fk_charge_from_ledger,fk_charge_to_ledger fk_charge_to_ledger 8 const 7
1 PRIMARY <derived2> ref key0 key0 17 test.charges.from_ledger_id,test.charges.id 2
2 LATERAL DERIVED transaction_items ref fk_items_transaction,fk_items_charge fk_items_charge 9 test.charges.id 2
2 LATERAL DERIVED transactions eq_ref PRIMARY,fk_transactions_ledger PRIMARY 8 test.transaction_items.transaction_id 1 Using where
EXPLAIN FORMAT=JSON SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
INNER JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "charges",
"access_type": "ref",
"possible_keys": ["PRIMARY", "fk_charge_from_ledger", "fk_charge_to_ledger"],
"key": "fk_charge_to_ledger",
"key_length": "8",
"used_key_parts": ["to_ledger_id"],
"ref": ["const"],
"rows": 7,
"filtered": 100
},
"table": {
"table_name": "<derived2>",
"access_type": "ref",
"possible_keys": ["key0"],
"key": "key0",
"key_length": "17",
"used_key_parts": ["ledger_id", "charge_id"],
"ref": ["test.charges.from_ledger_id", "test.charges.id"],
"rows": 2,
"filtered": 100,
"materialized": {
"lateral": 1,
"query_block": {
"select_id": 2,
"table": {
"table_name": "transaction_items",
"access_type": "ref",
"possible_keys": ["fk_items_transaction", "fk_items_charge"],
"key": "fk_items_charge",
"key_length": "9",
"used_key_parts": ["charge_id"],
"ref": ["test.charges.id"],
"rows": 2,
"filtered": 100
},
"table": {
"table_name": "transactions",
"access_type": "eq_ref",
"possible_keys": ["PRIMARY", "fk_transactions_ledger"],
"key": "PRIMARY",
"key_length": "8",
"used_key_parts": ["id"],
"ref": ["test.transaction_items.transaction_id"],
"rows": 1,
"filtered": 100,
"attached_condition": "transactions.ledger_id = charges.from_ledger_id"
}
}
}
}
}
}
set optimizer_switch='split_materialized=off';
SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
INNER JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id from_ledger_id to_ledger_id from_num_rows
2 1 2 1
3 1 2 1
5 3 2 1
8 3 2 1
10 3 2 1
12 3 2 1
13 3 2 1
18 1 2 1
EXPLAIN SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
INNER JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY charges ref PRIMARY,fk_charge_from_ledger,fk_charge_to_ledger fk_charge_to_ledger 8 const 7
1 PRIMARY <derived2> ref key0 key0 17 test.charges.from_ledger_id,test.charges.id 4
2 DERIVED transaction_items ALL fk_items_transaction NULL NULL NULL 40 Using temporary; Using filesort
2 DERIVED transactions eq_ref PRIMARY PRIMARY 8 test.transaction_items.transaction_id 1
INSERT INTO charges (id, from_ledger_id, to_ledger_id, amount) VALUES
(101, 4, 2, 100), (102, 7, 2, 200);
set optimizer_switch='split_materialized=on';
SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
LEFT JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id from_ledger_id to_ledger_id from_num_rows
2 1 2 1
3 1 2 1
5 3 2 1
8 3 2 1
10 3 2 1
12 3 2 1
13 3 2 1
18 1 2 1
101 4 2 NULL
102 7 2 NULL
EXPLAIN SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
LEFT JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY charges ref fk_charge_to_ledger fk_charge_to_ledger 8 const 9
1 PRIMARY <derived2> ref key0 key0 18 test.charges.from_ledger_id,test.charges.id 2
2 LATERAL DERIVED transaction_items ref fk_items_transaction,fk_items_charge fk_items_charge 9 test.charges.id 2
2 LATERAL DERIVED transactions eq_ref PRIMARY,fk_transactions_ledger PRIMARY 8 test.transaction_items.transaction_id 1 Using where
EXPLAIN FORMAT=JSON SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
LEFT JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
EXPLAIN
{
"query_block": {
"select_id": 1,
"table": {
"table_name": "charges",
"access_type": "ref",
"possible_keys": ["fk_charge_to_ledger"],
"key": "fk_charge_to_ledger",
"key_length": "8",
"used_key_parts": ["to_ledger_id"],
"ref": ["const"],
"rows": 9,
"filtered": 100
},
"table": {
"table_name": "<derived2>",
"access_type": "ref",
"possible_keys": ["key0"],
"key": "key0",
"key_length": "18",
"used_key_parts": ["ledger_id", "charge_id"],
"ref": ["test.charges.from_ledger_id", "test.charges.id"],
"rows": 2,
"filtered": 100,
"materialized": {
"lateral": 1,
"query_block": {
"select_id": 2,
"table": {
"table_name": "transaction_items",
"access_type": "ref",
"possible_keys": ["fk_items_transaction", "fk_items_charge"],
"key": "fk_items_charge",
"key_length": "9",
"used_key_parts": ["charge_id"],
"ref": ["test.charges.id"],
"rows": 2,
"filtered": 100
},
"table": {
"table_name": "transactions",
"access_type": "eq_ref",
"possible_keys": ["PRIMARY", "fk_transactions_ledger"],
"key": "PRIMARY",
"key_length": "8",
"used_key_parts": ["id"],
"ref": ["test.transaction_items.transaction_id"],
"rows": 1,
"filtered": 100,
"attached_condition": "transactions.ledger_id = charges.from_ledger_id"
}
}
}
}
}
}
set optimizer_switch='split_materialized=off';
SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
LEFT JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id from_ledger_id to_ledger_id from_num_rows
2 1 2 1
3 1 2 1
5 3 2 1
8 3 2 1
10 3 2 1
12 3 2 1
13 3 2 1
18 1 2 1
101 4 2 NULL
102 7 2 NULL
EXPLAIN SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
LEFT JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY charges ref fk_charge_to_ledger fk_charge_to_ledger 8 const 9
1 PRIMARY <derived2> ref key0 key0 18 test.charges.from_ledger_id,test.charges.id 4
2 DERIVED transaction_items ALL fk_items_transaction NULL NULL NULL 40 Using temporary; Using filesort
2 DERIVED transactions eq_ref PRIMARY PRIMARY 8 test.transaction_items.transaction_id 1
set optimizer_switch='split_materialized=default';
DROP TABLE transaction_items;
DROP TABLE transactions;
DROP TABLE charges;
DROP TABLE ledgers;
# End of 10.3 tests

142
mysql-test/main/derived_cond_pushdown.test
View file

@ -3711,4 +3711,146 @@ set optimizer_switch='split_materialized=default';
DROP TABLE t1,t2,t3;
--echo #
--echo # MDEV-27510: Splittable derived with grouping over two tables
--echo #
CREATE TABLE ledgers (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(32)
) ENGINE=MyISAM;
CREATE TABLE charges (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
from_ledger_id BIGINT UNSIGNED NOT NULL,
to_ledger_id BIGINT UNSIGNED NOT NULL,
amount INT NOT NULL,
KEY fk_charge_from_ledger (from_ledger_id),
KEY fk_charge_to_ledger (to_ledger_id)
) ENGINE=MyISAM;
CREATE TABLE transactions (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
ledger_id BIGINT UNSIGNED NOT NULL,
KEY fk_transactions_ledger (ledger_id)
) ENGINE=MyISAM;
CREATE TABLE transaction_items (
id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
transaction_id BIGINT UNSIGNED NOT NULL,
charge_id BIGINT UNSIGNED,
amount INT NOT NULL,
KEY fk_items_transaction (transaction_id),
KEY fk_items_charge (charge_id)
) ENGINE=MyISAM;
INSERT INTO ledgers (id, name) VALUES
(1, 'Anna'), (2, 'John'), (3, 'Fred');
INSERT INTO charges (id, from_ledger_id, to_ledger_id, amount) VALUES
(1, 2, 1, 200), (2, 1, 2, 330), (3, 1, 2, 640), (4, 3, 1, 640), (5, 3, 2, 1000),
(6, 3, 1, 660), (7, 2, 3, 650), (8, 3, 2, 160), (9, 2, 1, 740), (10, 3, 2, 310),
(11, 2, 1, 640), (12, 3, 2, 240), (13, 3, 2, 340), (14, 2, 1, 720),
(15, 2, 3, 100),
(16, 2, 3, 980), (17, 2, 1, 80), (18, 1, 2, 760), (19, 2, 3, 740),
(20, 2, 1, 990);
INSERT INTO transactions (id, ledger_id) VALUES
(2, 1), (3, 1), (5, 1), (8, 1), (12, 1), (18, 1), (22, 1), (28, 1),
(34, 1), (35, 1),
(40, 1), (1, 2), (4, 2), (6, 2), (10, 2), (13, 2), (16, 2), (17, 2),
(20, 2), (21, 2),
(24, 2), (26, 2), (27, 2), (29, 2), (31, 2), (33, 2), (36, 2), (37, 2),
(39, 2), (7, 3),
(9, 3), (11, 3), (14, 3), (15, 3), (19, 3), (23, 3), (25, 3), (30, 3),
(32, 3), (38, 3);
INSERT INTO transaction_items (id, transaction_id, charge_id, amount) VALUES
(1, 1, 1, -200), (2, 2, 1, 200), (3, 3, 2, -330), (4, 4, 2, 330),
(5, 5, 3, -640),
(6, 6, 3, 640), (7, 7, 4, -640), (8, 8, 4, 640), (9, 9, 5, -1000),
(10, 10, 5, 1000),
(11, 11, 6, -660), (12, 12, 6, 660), (13, 13, 7, -650), (14, 14, 7, 650),
(15, 15, 8, -160),
(16, 16, 8, 160), (17, 17, 9, -740), (18, 18, 9, 740), (19, 19, 10, -310),
(20, 20, 10, 310),
(21, 21, 11, -640), (22, 22, 11, 640), (23, 23, 12, -240), (24, 24, 12, 240),
(25, 25, 13, -340),
(26, 26, 13, 340), (27, 27, 14, -720), (28, 28, 14, 720), (29, 29, 15, -100),
(30, 30, 15, 100),
(31, 31, 16, -980), (32, 32, 16, 980), (33, 33, 17, -80), (34, 34, 17, 80),
(35, 35, 18, -760),
(36, 36, 18, 760), (37, 37, 19, -740), (38, 38, 19, 740), (39, 39, 20, -990),
(40, 40, 20, 990);
ANALYZE TABLE ledgers, charges, transactions, transaction_items;
let $q=
SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
INNER JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
set optimizer_switch='split_materialized=on';
eval $q;
eval EXPLAIN $q;
eval EXPLAIN FORMAT=JSON $q;
set optimizer_switch='split_materialized=off';
eval $q;
eval EXPLAIN $q;
INSERT INTO charges (id, from_ledger_id, to_ledger_id, amount) VALUES
(101, 4, 2, 100), (102, 7, 2, 200);
let $q1=
SELECT
charges.id,
charges.from_ledger_id,
charges.to_ledger_id,
from_agg_items.num_rows AS from_num_rows
FROM charges
LEFT JOIN (
SELECT
transactions.ledger_id,
transaction_items.charge_id,
count(*) as num_rows
FROM transaction_items
INNER JOIN transactions ON transaction_items.transaction_id = transactions.id
GROUP BY transactions.ledger_id, transaction_items.charge_id
) AS from_agg_items
ON from_agg_items.charge_id = charges.id AND
from_agg_items.ledger_id = charges.from_ledger_id
WHERE charges.to_ledger_id = 2;
set optimizer_switch='split_materialized=on';
eval $q1;
eval EXPLAIN $q1;
eval EXPLAIN FORMAT=JSON $q1;
set optimizer_switch='split_materialized=off';
eval $q1;
eval EXPLAIN $q1;
set optimizer_switch='split_materialized=default';
DROP TABLE transaction_items;
DROP TABLE transactions;
DROP TABLE charges;
DROP TABLE ledgers;
--echo # End of 10.3 tests

64
sql/opt_split.cc
View file

@ -1048,16 +1048,16 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(double record_count,
Inject equalities for splitting used by the materialization join
@param
remaining_tables used to filter out the equalities that cannot
excluded_tables used to filter out the equalities that cannot
be pushed.
@details
This function is called by JOIN_TAB::fix_splitting that is used
to fix the chosen splitting of a splittable materialized table T
in the final query execution plan. In this plan the table T
is joined just before the 'remaining_tables'. So all equalities
usable for splitting whose right parts do not depend on any of
remaining tables can be pushed into join for T.
This function injects equalities pushed into a derived table T for which
the split optimization has been chosen by the optimizer. The function
is called by JOIN::inject_splitting_cond_for_all_tables_with_split_op().
All equalities usable for splitting T whose right parts do not depend on
any of the 'excluded_tables' can be pushed into the where clause of the
derived table T.
The function also marks the select that specifies T as
UNCACHEABLE_DEPENDENT_INJECTED.
@ -1066,7 +1066,7 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(double record_count,
true on failure
*/
bool JOIN::inject_best_splitting_cond(table_map remaining_tables)
bool JOIN::inject_best_splitting_cond(table_map excluded_tables)
{
Item *inj_cond= 0;
List<Item> *inj_cond_list= &spl_opt_info->inj_cond_list;
@ -1074,7 +1074,7 @@ bool JOIN::inject_best_splitting_cond(table_map remaining_tables)
KEY_FIELD *added_key_field;
while ((added_key_field= li++))
{
if (remaining_tables & added_key_field->val->used_tables())
if (excluded_tables & added_key_field->val->used_tables())
continue;
if (inj_cond_list->push_back(added_key_field->cond, thd->mem_root))
return true;
@ -1168,8 +1168,6 @@ bool JOIN_TAB::fix_splitting(SplM_plan_info *spl_plan,
memcpy((char *) md_join->best_positions,
(char *) spl_plan->best_positions,
sizeof(POSITION) * md_join->table_count);
if (md_join->inject_best_splitting_cond(remaining_tables))
return true;
/*
This is called for a proper work of JOIN::get_best_combination()
called for the join that materializes T
@ -1213,7 +1211,8 @@ bool JOIN::fix_all_splittings_in_plan()
if (tab->table->is_splittable())
{
SplM_plan_info *spl_plan= cur_pos->spl_plan;
if (tab->fix_splitting(spl_plan, all_tables & ~prev_tables,
if (tab->fix_splitting(spl_plan,
all_tables & ~prev_tables,
tablenr < const_tables ))
return true;
}
@ -1221,3 +1220,44 @@ bool JOIN::fix_all_splittings_in_plan()
}
return false;
}
/**
@brief
Inject splitting conditions into WHERE of split derived
@details
The function calls JOIN_TAB::inject_best_splitting_cond() for each
materialized derived table T used in this join for which the split
optimization has been chosen by the optimizer. It is done in order to
inject equalities pushed into the where clause of the specification
of T that would be helpful to employ the splitting technique.
@retval
false on success
true on failure
*/
bool JOIN::inject_splitting_cond_for_all_tables_with_split_opt()
{
table_map prev_tables= 0;
table_map all_tables= (table_map(1) << table_count) - 1;
for (uint tablenr= 0; tablenr < table_count; tablenr++)
{
POSITION *cur_pos= &best_positions[tablenr];
JOIN_TAB *tab= cur_pos->table;
prev_tables|= tab->table->map;
if (!(tab->table->is_splittable() && cur_pos->spl_plan))
continue;
SplM_opt_info *spl_opt_info= tab->table->spl_opt_info;
JOIN *join= spl_opt_info->join;
/*
Currently the equalities referencing columns of SJM tables with
look-up access cannot be pushed into materialized derived.
*/
if (join->inject_best_splitting_cond((all_tables & ~prev_tables) |
sjm_lookup_tables))
return true;
}
return false;
}

18
sql/sql_select.cc
View file

@ -9755,6 +9755,9 @@ bool JOIN::get_best_combination()
hash_join= FALSE;
fix_semijoin_strategies_for_picked_join_order(this);
if (inject_splitting_cond_for_all_tables_with_split_opt())
DBUG_RETURN(TRUE);
JOIN_TAB_RANGE *root_range;
if (!(root_range= new (thd->mem_root) JOIN_TAB_RANGE))
@ -21863,21 +21866,6 @@ make_cond_for_table_from_pred(THD *thd, Item *root_cond, Item *cond,
cond->marker=3; // Checked when read
return (COND*) 0;
}
/*
If cond is an equality injected for split optimization then
a. when retain_ref_cond == false : cond is removed unconditionally
(cond that supports ref access is removed by the preceding code)
b. when retain_ref_cond == true : cond is removed if it does not
support ref access
*/
if (left_item->type() == Item::FIELD_ITEM &&
is_eq_cond_injected_for_split_opt((Item_func_eq *) cond) &&
(!retain_ref_cond ||
!test_if_ref(root_cond, (Item_field*) left_item,right_item)))
{
cond->marker=3;
return (COND*) 0;
}
}
cond->marker=2;
cond->set_join_tab_idx(join_tab_idx_arg);

1
sql/sql_select.h
View file

@ -1764,6 +1764,7 @@ public:
void add_keyuses_for_splitting();
bool inject_best_splitting_cond(table_map remaining_tables);
bool fix_all_splittings_in_plan();
bool inject_splitting_cond_for_all_tables_with_split_opt();
bool transform_in_predicates_into_in_subq(THD *thd);
private: