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Bug#119198 fix bug optimizer reverse index scan give incorrect result #633

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Bug#119198 fix bug optimizer reverse index scan give incorrect result #633

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67 changes: 67 additions & 0 deletions mysql-test/r/optimizer_reverse_index_range_scan_bug.result
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Original file line number Diff line number Diff line change
@@ -0,0 +1,67 @@
#
# Bug#119198 Reverse index range scan give incorrect result.
#
CREATE TABLE temp_table (
id bigint unsigned NOT NULL AUTO_INCREMENT,
col1 tinyint unsigned NOT NULL,
col2 tinyint unsigned NOT NULL,
PRIMARY KEY (id),
KEY temp_table_idx01 (col1)
) ENGINE=InnoDB;
# 2. Insert Data
INSERT INTO temp_table (id, col1, col2)
VALUES (10, 1, 4);
INSERT INTO temp_table (id, col1, col2)
VALUES (20, 1, 4);
# 3. Run Query
SELECT * FROM temp_table;
id col1 col2
10 1 4
20 1 4
# Verify table should contain 2 records id#10, id#20 respectively
#
EXPLAIN
SELECT * FROM temp_table
WHERE col1 >= 1 AND col1 <= 1
ORDER BY col1 DESC, id DESC
LIMIT 1;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE temp_table NULL range temp_table_idx01 temp_table_idx01 1 NULL 2 100.00 Using index condition; Backward index scan
# Query should use reverse index scan range
#
SELECT * FROM temp_table
WHERE col1 >= 1 AND col1 <= 1
ORDER BY col1 DESC, id DESC
LIMIT 1;
id col1 col2
20 1 4
# Query should return valid result with EQ_RANGE ordering by col1 desc limit 1 which is id#20
#
SELECT * FROM temp_table
WHERE col1 >= 1 AND col1 <= 1
ORDER BY col1 DESC, id DESC
LIMIT 2;
id col1 col2
20 1 4
10 1 4
# Query should return valid result with EQ_RANGE ordering by col1 desc limit 2 which are id#20, id#10
#
SELECT * FROM temp_table
WHERE col1 >= 0 AND col1 <= 5
ORDER BY col1 DESC, id DESC
LIMIT 1;
id col1 col2
20 1 4
# Query should return valid result with EQ_RANGE ordering by col1 desc limit 1 which is id#20
#
SELECT * FROM temp_table
WHERE col1 >= 0 AND col1 <= 5
ORDER BY col1 DESC, id DESC
LIMIT 2;
id col1 col2
20 1 4
10 1 4
# Query should return valid result with EQ_RANGE ordering by col1 desc limit 2 which are id#20, id#10
#
# 4. Clean up
DROP TABLE temp_table;
69 changes: 69 additions & 0 deletions mysql-test/t/optimizer_reverse_index_range_scan_bug.test
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Original file line number Diff line number Diff line change
@@ -0,0 +1,69 @@
--source include/have_debug_sync.inc

--echo #
--echo # Bug#119198 Reverse index range scan give incorrect result.
--echo #

CREATE TABLE temp_table (
id bigint unsigned NOT NULL AUTO_INCREMENT,
col1 tinyint unsigned NOT NULL,
col2 tinyint unsigned NOT NULL,
PRIMARY KEY (id),
KEY temp_table_idx01 (col1)
) ENGINE=InnoDB;

--echo # 2. Insert Data

INSERT INTO temp_table (id, col1, col2)
VALUES (10, 1, 4);

INSERT INTO temp_table (id, col1, col2)
VALUES (20, 1, 4);

--echo # 3. Run Query
--disable_warnings
SELECT * FROM temp_table;
--echo # Verify table should contain 2 records id#10, id#20 respectively
--echo #


EXPLAIN
SELECT * FROM temp_table
WHERE col1 >= 1 AND col1 <= 1
ORDER BY col1 DESC, id DESC
LIMIT 1;
--enable_warnings
--echo # Query should use reverse index scan range
--echo #


SELECT * FROM temp_table
WHERE col1 >= 1 AND col1 <= 1
ORDER BY col1 DESC, id DESC
LIMIT 1;
--echo # Query should return valid result with EQ_RANGE ordering by col1 desc limit 1 which is id#20
--echo #

SELECT * FROM temp_table
WHERE col1 >= 1 AND col1 <= 1
ORDER BY col1 DESC, id DESC
LIMIT 2;
--echo # Query should return valid result with EQ_RANGE ordering by col1 desc limit 2 which are id#20, id#10
--echo #

SELECT * FROM temp_table
WHERE col1 >= 0 AND col1 <= 5
ORDER BY col1 DESC, id DESC
LIMIT 1;
--echo # Query should return valid result with EQ_RANGE ordering by col1 desc limit 1 which is id#20
--echo #

SELECT * FROM temp_table
WHERE col1 >= 0 AND col1 <= 5
ORDER BY col1 DESC, id DESC
LIMIT 2;
--echo # Query should return valid result with EQ_RANGE ordering by col1 desc limit 2 which are id#20, id#10
--echo #

--echo # 4. Clean up
DROP TABLE temp_table;
5 changes: 3 additions & 2 deletions sql/sql_optimizer.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -9906,8 +9906,9 @@ static bool make_join_query_block(JOIN *join, Item *cond) {
used_index(tab->range_scan()) != MAX_KEY) {
const uint ref_key = used_index(tab->range_scan());
bool skip_quick;
uint used_key_parts = 0;
read_direction = test_if_order_by_key(
&join->order, tab->table(), ref_key, nullptr, &skip_quick);
&join->order, tab->table(), ref_key, &used_key_parts, &skip_quick);
if (skip_quick) read_direction = 0;
/*
If the index provides order there is no need to recheck
Expand All @@ -9921,7 +9922,7 @@ static bool make_join_query_block(JOIN *join, Item *cond) {
if (read_direction == 1 ||
(read_direction == -1 &&
reverse_sort_possible(tab->range_scan()) &&
!make_reverse(get_used_key_parts(tab->range_scan()),
!make_reverse(std::max(used_key_parts, get_used_key_parts(tab->range_scan())),
tab->range_scan()))) {
recheck_reason = DONT_RECHECK;
}
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