Skip to content

M
mariadb
Commit 7714739b authored by Igor Babaev's avatar Igor Babaev
Browse files
Options

Fixed bug mdev-585 (LP bug #637962) 

If, when executing a query with ORDER BY col LIMIT n, the optimizer chose
an index-merge scan to access the table containing col while there existed
an index defined over col then optimizer did not consider the possibility
of using an alternative range scan by this index to avoid filesort. This
could cause a performance degradation if the optimizer flag index_merge was
set up to 'on'.
parent 9b6fe965
Hide whitespace changes
Inline Side-by-side
Showing with 356 additions and 6 deletions
mysql-test/r/range_vs_index_merge.result
View file @ 7714739b
......@@ -1221,6 +1221,150 @@ Lugansk UKR 469000
Seattle USA 563374
Caracas VEN 1975294
set optimizer_switch=@save_optimizer_switch;
#
# Bug mdev-585: range vs index-merge with ORDER BY ... LIMIT n
# (LP bug #637962)
#
DROP INDEX CountryPopulation ON City;
DROP INDEX CountryName ON City;
DROP INDEX CityName on City;
CREATE INDEX Name ON City(Name);
CREATE INDEX Population ON City(Population);
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City index_merge Country,Name,Population Name,Country 35,3 NULL # Using sort_union(Name,Country); Using where
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000);
ID Name Country Population
384 Cabo Frio BRA 119503
387 Camaragibe BRA 118968
403 Catanduva BRA 107761
412 Cachoeirinha BRA 103240
508 Watford GBR 113080
509 Ipswich GBR 114000
510 Slough GBR 112000
511 Exeter GBR 111000
512 Cheltenham GBR 106000
513 Gloucester GBR 107000
514 Saint Helens GBR 106293
515 Sutton Coldfield GBR 106001
516 York GBR 104425
517 Oldham GBR 103931
518 Basildon GBR 100924
519 Worthing GBR 100000
635 Mallawi EGY 119283
636 Bilbays EGY 113608
637 Mit Ghamr EGY 101801
638 al-Arish EGY 100447
701 Tarragona ESP 113016
702 Lleida (Lérida) ESP 112207
703 Jaén ESP 109247
704 Ourense (Orense) ESP 109120
705 Mataró ESP 104095
706 Algeciras ESP 103106
707 Marbella ESP 101144
759 Gonder ETH 112249
869 Cabuyao PHL 106630
870 Calapan PHL 105910
873 Cauayan PHL 103952
903 Serekunda GMB 102600
909 Sohumi GEO 111700
913 Tema GHA 109975
914 Sekondi-Takoradi GHA 103653
924 Villa Nueva GTM 101295
1844 Cape Breton CAN 114733
1847 Cambridge CAN 109186
2406 Herakleion GRC 116178
2407 Kallithea GRC 114233
2408 Larisa GRC 113090
2908 Cajamarca PER 108009
3002 Besançon FRA 117733
3003 Caen FRA 113987
3004 Orléans FRA 113126
3005 Mulhouse FRA 110359
3006 Rouen FRA 106592
3007 Boulogne-Billancourt FRA 106367
3008 Perpignan FRA 105115
3009 Nancy FRA 103605
3411 Ceyhan TUR 102412
3567 Carúpano VEN 119639
3568 Catia La Mar VEN 117012
3571 Calabozo VEN 107146
3786 Cam Ranh VNM 114041
3792 Tartu EST 101246
4002 Carrollton USA 109576
4027 Cape Coral USA 102286
4032 Cambridge USA 101355
SHOW STATUS LIKE 'Handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 2
Handler_read_next 385
Handler_read_prev 0
Handler_read_rnd 377
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City range Country,Name,Population Population 4 NULL # Using where
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
ID Name Country Population
519 Worthing GBR 100000
638 al-Arish EGY 100447
518 Basildon GBR 100924
707 Marbella ESP 101144
3792 Tartu EST 101246
SHOW STATUS LIKE 'Handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_next 59
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
set optimizer_switch='index_merge=off';
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City range Country,Name,Population Population 4 NULL # Using index condition; Using where
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
ID Name Country Population
519 Worthing GBR 100000
638 al-Arish EGY 100447
518 Basildon GBR 100924
707 Marbella ESP 101144
3792 Tartu EST 101246
SHOW STATUS LIKE 'Handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_next 59
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
set optimizer_switch=@save_optimizer_switch;
DROP DATABASE world;
use test;
CREATE TABLE t1 (
......
mysql-test/r/range_vs_index_merge_innodb.result
View file @ 7714739b
......@@ -1222,6 +1222,150 @@ Lugansk UKR 469000
Seattle USA 563374
Caracas VEN 1975294
set optimizer_switch=@save_optimizer_switch;
#
# Bug mdev-585: range vs index-merge with ORDER BY ... LIMIT n
# (LP bug #637962)
#
DROP INDEX CountryPopulation ON City;
DROP INDEX CountryName ON City;
DROP INDEX CityName on City;
CREATE INDEX Name ON City(Name);
CREATE INDEX Population ON City(Population);
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City index_merge Country,Name,Population Name,Country 35,3 NULL # Using sort_union(Name,Country); Using where
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000);
ID Name Country Population
384 Cabo Frio BRA 119503
387 Camaragibe BRA 118968
403 Catanduva BRA 107761
412 Cachoeirinha BRA 103240
508 Watford GBR 113080
509 Ipswich GBR 114000
510 Slough GBR 112000
511 Exeter GBR 111000
512 Cheltenham GBR 106000
513 Gloucester GBR 107000
514 Saint Helens GBR 106293
515 Sutton Coldfield GBR 106001
516 York GBR 104425
517 Oldham GBR 103931
518 Basildon GBR 100924
519 Worthing GBR 100000
635 Mallawi EGY 119283
636 Bilbays EGY 113608
637 Mit Ghamr EGY 101801
638 al-Arish EGY 100447
701 Tarragona ESP 113016
702 Lleida (Lérida) ESP 112207
703 Jaén ESP 109247
704 Ourense (Orense) ESP 109120
705 Mataró ESP 104095
706 Algeciras ESP 103106
707 Marbella ESP 101144
759 Gonder ETH 112249
869 Cabuyao PHL 106630
870 Calapan PHL 105910
873 Cauayan PHL 103952
903 Serekunda GMB 102600
909 Sohumi GEO 111700
913 Tema GHA 109975
914 Sekondi-Takoradi GHA 103653
924 Villa Nueva GTM 101295
1844 Cape Breton CAN 114733
1847 Cambridge CAN 109186
2406 Herakleion GRC 116178
2407 Kallithea GRC 114233
2408 Larisa GRC 113090
2908 Cajamarca PER 108009
3002 Besançon FRA 117733
3003 Caen FRA 113987
3004 Orléans FRA 113126
3005 Mulhouse FRA 110359
3006 Rouen FRA 106592
3007 Boulogne-Billancourt FRA 106367
3008 Perpignan FRA 105115
3009 Nancy FRA 103605
3411 Ceyhan TUR 102412
3567 Carúpano VEN 119639
3568 Catia La Mar VEN 117012
3571 Calabozo VEN 107146
3786 Cam Ranh VNM 114041
3792 Tartu EST 101246
4002 Carrollton USA 109576
4027 Cape Coral USA 102286
4032 Cambridge USA 101355
SHOW STATUS LIKE 'Handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 2
Handler_read_next 385
Handler_read_prev 0
Handler_read_rnd 377
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City range Country,Name,Population Population 4 NULL # Using where
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
ID Name Country Population
519 Worthing GBR 100000
638 al-Arish EGY 100447
518 Basildon GBR 100924
707 Marbella ESP 101144
3792 Tartu EST 101246
SHOW STATUS LIKE 'Handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_next 59
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
set optimizer_switch='index_merge=off';
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City range Country,Name,Population Population 4 NULL # Using index condition; Using where
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
ID Name Country Population
519 Worthing GBR 100000
638 al-Arish EGY 100447
518 Basildon GBR 100924
707 Marbella ESP 101144
3792 Tartu EST 101246
SHOW STATUS LIKE 'Handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_next 59
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
set optimizer_switch=@save_optimizer_switch;
DROP DATABASE world;
use test;
CREATE TABLE t1 (
......
mysql-test/t/range_vs_index_merge.test
View file @ 7714739b
......@@ -675,6 +675,64 @@ SELECT Name, Country, Population FROM City WHERE
$cond;
set optimizer_switch=@save_optimizer_switch;
--echo #
--echo # Bug mdev-585: range vs index-merge with ORDER BY ... LIMIT n
--echo # (LP bug #637962)
--echo #
DROP INDEX CountryPopulation ON City;
DROP INDEX CountryName ON City;
DROP INDEX CityName on City;
CREATE INDEX Name ON City(Name);
CREATE INDEX Population ON City(Population);
--replace_column 9 #
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000);
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000);
SHOW STATUS LIKE 'Handler_read_%';
--replace_column 9 #
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
SHOW STATUS LIKE 'Handler_read_%';
set optimizer_switch='index_merge=off';
--replace_column 9 #
EXPLAIN
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
SHOW STATUS LIKE 'Handler_read_%';
set optimizer_switch=@save_optimizer_switch;
DROP DATABASE world;
......
sql/sql_select.cc
View file @ 7714739b
......@@ -18079,15 +18079,18 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit_arg,
*/
if (quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_MERGE ||
quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_INTERSECT ||
quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_INTERSECT ||
quick_type == QUICK_SELECT_I::QS_TYPE_ROR_UNION ||
quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT)
goto use_filesort;
ref_key= select->quick->index;
ref_key_parts= select->quick->used_key_parts;
ref_key= MAX_KEY;
else
{
ref_key= select->quick->index;
ref_key_parts= select->quick->used_key_parts;
}
}
if (ref_key >= 0)
if (ref_key >= 0 && ref_key != MAX_KEY)
{
/*
We come here when there is a REF key.
......@@ -18229,7 +18232,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit_arg,
else
keys= usable_keys;
if (ref_key >= 0 && table->covering_keys.is_set(ref_key))
if (ref_key >= 0 && ref_key != MAX_KEY &&
table->covering_keys.is_set(ref_key))
ref_key_quick_rows= table->quick_rows[ref_key];
read_time= join->best_positions[tablenr].read_time;
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7