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MDEV-27426 Wrong result upon query using index_merge with DESC key

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Make QUICK_RANGE_SELECT::cmp_next() aware of reverse-ordered key parts.

(QUICK_RANGE_SELECT::cmp_prev() uses key_cmp() and so it already works
correctly)
This commit is contained in:
Sergei Petrunia
2022-01-10 16:19:03 +03:00
committed by Sergei Golubchik
parent 96bdda6c96
commit 62760af4df
3 changed files with 25 additions and 4 deletions
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10
mysql-test/main/desc_index_range.result
View File

@@ -179,3 +179,13 @@ json_detailed(json_extract(trace, '$**.potential_group_range_indexes'))
] ]
drop table t1; drop table t1;
set optimizer_trace=default; set optimizer_trace=default;
#
# MDEV-27426: Wrong result upon query using index_merge with DESC key
#
CREATE OR REPLACE TABLE t1 (pk INT, a INT, b int, KEY(a), PRIMARY KEY(pk DESC)) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,4,5),(2,9,6),(3,NULL,7),(4,NULL,8);
SELECT * FROM t1 WHERE pk > 10 OR a > 0;
pk a b
1 4 5
2 9 6
DROP TABLE t1;

10
mysql-test/main/desc_index_range.test
View File

@@ -86,3 +86,13 @@ from information_schema.optimizer_trace;
drop table t1; drop table t1;
set optimizer_trace=default; set optimizer_trace=default;
--echo #
--echo # MDEV-27426: Wrong result upon query using index_merge with DESC key
--echo #
CREATE OR REPLACE TABLE t1 (pk INT, a INT, b int, KEY(a), PRIMARY KEY(pk DESC)) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,4,5),(2,9,6),(3,NULL,7),(4,NULL,8);
SELECT * FROM t1 WHERE pk > 10 OR a > 0;
DROP TABLE t1;

9
sql/opt_range.cc
View File

@@ -13079,24 +13079,25 @@ int QUICK_RANGE_SELECT::cmp_next(QUICK_RANGE *range_arg)
key+= store_length, key_part++) key+= store_length, key_part++)
{ {
int cmp; int cmp;
bool reverse= MY_TEST(key_part->flag & HA_REVERSE_SORT);
store_length= key_part->store_length; store_length= key_part->store_length;
if (key_part->null_bit) if (key_part->null_bit)
{ {
if (*key) if (*key)
{ {
if (!key_part->field->is_null()) if (!key_part->field->is_null())
return 1; return reverse ? 0 : 1;
continue; continue;
} }
else if (key_part->field->is_null()) else if (key_part->field->is_null())
return 0; return reverse ? 1 : 0;
key++; // Skip null byte key++; // Skip null byte
store_length--; store_length--;
} }
if ((cmp=key_part->field->key_cmp(key, key_part->length)) < 0) if ((cmp=key_part->field->key_cmp(key, key_part->length)) < 0)
return 0; return reverse ? 1 : 0;
if (cmp > 0) if (cmp > 0)
return 1; return reverse ? 0 : 1;
} }
return (range_arg->flag & NEAR_MAX) ? 1 : 0; // Exact match return (range_arg->flag & NEAR_MAX) ? 1 : 0; // Exact match
} }