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thejaka-kanewalaGitHub Enterprise
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Fixing optimizer code to generate better plans when optimizer_use_condition_selectivity=4 (#36)
The Cause: The condition selectivity for a table is calculated in “calculate_cond_selectivity_for_table” function in sql/opt_range.cc. When calculating selectivity for indexes, the function iterates through all the used keyparts and calculates selectivity. However, when we have extended keys enabled and if a primary key part appear in the query in addition to a normal key, the selectivity for the primary key part is not calculated. Inside the “calculate_cond_selectivity_for_table” function, when calculate selectivity for an index the code marks all the key parts of that key as processed. When extended keys are enabled, the code also marks primary key parts as processed. This causes primary key based condition selectivities to be not calculated as the key parts are already marked as handled. The Fix: The code is modified to only consider user-defined keyparts when calculating the index selectivity. Effect on existing test cases: The following test case results were modified to match the output of the modified code. join_cache.result opt_trace.result Signed-off-by: Thejaka Kanewala <thejaka.kanewala@servicenow.com>
1 parent b0cdf2e commit a980cc9

5 files changed

Lines changed: 220 additions & 34 deletions

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‎mysql-test/main/join_cache.result‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6216,7 +6216,7 @@ EXPLAIN
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"key_length": "10",
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"used_key_parts": ["kp1", "kp2"],
62186218
"rows": 836,
6219-
"filtered": 76.434,
6219+
"filtered": 8.36,
62206220
"index_condition": "b.kp2 <= 10",
62216221
"attached_condition": "b.kp2 <= 10 and b.col1 + 1 < 33333"
62226222
},

‎mysql-test/main/mdev-25830.result‎

Lines changed: 68 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,68 @@
1+
SET SESSION STORAGE_ENGINE='InnoDB';
2+
set @innodb_stats_persistent_save= @@innodb_stats_persistent;
3+
set @innodb_stats_persistent_sample_pages_save=
4+
@@innodb_stats_persistent_sample_pages;
5+
set global innodb_stats_persistent= 1;
6+
set global innodb_stats_persistent_sample_pages=100;
7+
set optimizer_use_condition_selectivity=4;
8+
explain format= json SELECT sysapproval_approver0.`sys_id` FROM ((sysapproval_approver sysapproval_approver0 INNER JOIN task task1 ON sysapproval_approver0.`sysapproval` = task1.`sys_id` AND ((task1.`sys_domain_path` = '/' OR task1.`sys_domain_path` LIKE '!!!/!!#/!!$/%' OR task1.`sys_domain_path` LIKE '!!!/!!!/%'))) INNER JOIN task task2 ON task1.`parent` = task2.`sys_id` AND ((task2.`sys_domain_path` = '/' OR task2.`sys_domain_path` LIKE '!!!/!!#/!!$/%' OR task2.`sys_domain_path` LIKE '!!!/!!!/%'))) WHERE task2.`sys_id` LIKE '8e7792a7dbfffb00fff8a345ca961934%' AND (sysapproval_approver0.`sys_domain_path` = '/' OR sysapproval_approver0.`sys_domain_path` LIKE '!!!/!!#/!!$/%' OR sysapproval_approver0.`sys_domain_path` LIKE '!!!/!!!/%') ORDER BY sysapproval_approver0.`order` LIMIT 0, 50;
9+
EXPLAIN
10+
{
11+
"query_block": {
12+
"select_id": 1,
13+
"filesort": {
14+
"sort_key": "sysapproval_approver0.`order`",
15+
"temporary_table": {
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"table": {
17+
"table_name": "task2",
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"access_type": "range",
19+
"possible_keys": ["PRIMARY", "sys_class_name_2", "sys_domain_path"],
20+
"key": "PRIMARY",
21+
"key_length": "96",
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"used_key_parts": ["sys_id"],
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"rows": 1,
24+
"filtered": 98,
25+
"attached_condition": "task2.sys_id like '8e7792a7dbfffb00fff8a345ca961934%' and (task2.sys_domain_path = '/' or task2.sys_domain_path like '!!!/!!#/!!$/%' or task2.sys_domain_path like '!!!/!!!/%')"
26+
},
27+
"table": {
28+
"table_name": "task1",
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"access_type": "ref",
30+
"possible_keys": [
31+
"PRIMARY",
32+
"task_parent",
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"sys_class_name_2",
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"sys_domain_path"
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],
36+
"key": "task_parent",
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"key_length": "99",
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"used_key_parts": ["parent"],
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"ref": ["mdev25830.task2.sys_id"],
40+
"rows": 1,
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"filtered": 100,
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"index_condition": "task1.parent = task2.sys_id",
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"attached_condition": "task1.sys_domain_path = '/' or task1.sys_domain_path like '!!!/!!#/!!$/%' or task1.sys_domain_path like '!!!/!!!/%'"
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},
45+
"table": {
46+
"table_name": "sysapproval_approver0",
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"access_type": "ref",
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"possible_keys": [
49+
"sysapproval_approver_ref5",
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"sys_domain_path",
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"sysapproval_approver_CHG1975376"
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],
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"key": "sysapproval_approver_ref5",
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"key_length": "99",
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"used_key_parts": ["sysapproval"],
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"ref": ["mdev25830.task1.sys_id"],
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"rows": 1,
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"filtered": 100,
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"index_condition": "sysapproval_approver0.sysapproval = task1.sys_id",
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"attached_condition": "sysapproval_approver0.sys_domain_path = '/' or sysapproval_approver0.sys_domain_path like '!!!/!!#/!!$/%' or sysapproval_approver0.sys_domain_path like '!!!/!!!/%'"
61+
}
62+
}
63+
}
64+
}
65+
}
66+
set global innodb_stats_persistent= @innodb_stats_persistent_save;
67+
set global innodb_stats_persistent_sample_pages=
68+
@innodb_stats_persistent_sample_pages_save;

‎mysql-test/main/mdev-25830.test‎

Lines changed: 72 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,72 @@
1+
#
2+
# MDEV-25830: optimizer_use_condition_selectivity=4 sometimes produces worse plan than optimizer_use_condition_selectivity=1
3+
# https://jira.mariadb.org/browse/MDEV-25830
4+
#
5+
--source include/innodb_prefix_index_cluster_optimization.inc
6+
7+
SET SESSION STORAGE_ENGINE='InnoDB';
8+
9+
set @innodb_stats_persistent_save= @@innodb_stats_persistent;
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set @innodb_stats_persistent_sample_pages_save=
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@@innodb_stats_persistent_sample_pages;
12+
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set global innodb_stats_persistent= 1;
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set global innodb_stats_persistent_sample_pages=100;
15+
16+
--disable_query_log
17+
--disable_result_log
18+
--disable_warnings
19+
20+
create database if not exists mdev25830;
21+
use mdev25830;
22+
DROP TABLE IF EXISTS `sysapproval_approver`;
23+
CREATE TABLE `sysapproval_approver` (
24+
`order` int(11) DEFAULT NULL,
25+
`sysapproval` varchar(32) DEFAULT NULL,
26+
`sys_id` char(32) NOT NULL DEFAULT '',
27+
`sys_domain_path` varchar(255) DEFAULT NULL,
28+
PRIMARY KEY (`sys_id`),
29+
KEY `sysapproval_approver_ref5` (`sysapproval`),
30+
KEY `sys_domain_path` (`sys_domain_path`),
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KEY `sysapproval_approver_CHG1975376` (`sys_domain_path`,`sysapproval`)
32+
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
33+
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INSERT INTO `sysapproval_approver` VALUES (NULL,'c00004d787a8a5003fff83bdff434dea','000004d787a8a5003fff83bdff434dee','!!!/!!#/!!$/'),(NULL,NULL,'00000741db8bfb480be6a345ca96198e','!!!/!!#/!!$/'),(NULL,NULL,'00001605dbce48d0f7fca851ca961967','!!!/!!#/!!$/'),(NULL,'23b53105db2f324c5a4af85e0f96194e','000016c1db6ffa445d2f7aa31f9619a0','!!!/!!#/!!$/'),(NULL,NULL,'00001730dbe24890f7fca851ca9619aa','!!!/!!#/!!$/'),(NULL,NULL,'000017a01b127b00ada243f6fe4bcb8c','!!!/!!#/!!$/'),(NULL,'7f660139db6088185ed4a851ca961986','00001ab1dbecc8185ed4a851ca961970','!!!/!!#/!!$/'),(NULL,'6226cd801b19dc10a59033f2cd4bcb22','00001d84db9918505ed4a851ca96193f','!!!/!!!/(8]/'),(NULL,NULL,'00002246db83874002f17c541f961999','!!!/!!#/!!$/'),(NULL,NULL,'000026e01b9eb700ada243f6fe4bcbc5','!!!/!!#/!!$/'),(NULL,NULL,'000028e16f064e807b658e4c2c3ee4ae','!!!/!!#/!!$/'),(NULL,NULL,'00002914dba8670c54250b55ca961928','!!!/!!#/!!$/'),(NULL,NULL,'00002914dba8670c54250b55ca961931','!!!/!!#/!!$/'),(NULL,NULL,'00002914dba8670c54250b55ca96193a','!!!/!!#/!!$/'),(NULL,NULL,'00002914dba8670c54250b55ca961943','!!!/!!#/!!$/'),(NULL,NULL,'000030a4dbb90b40002af47e0f9619b1','!!!/!!#/!!$/'),(NULL,NULL,'000033fedb41fb041cd8a345ca9619fa','!!!/!!#/!!$/'),(NULL,NULL,'0000341ddb4ce3804ac3a851ca961916','!!!/!!#/!!$/'),(NULL,NULL,'0000393ddb709b002b6dfb651f961908','!!!/!!#/!!$/'),(NULL,'a81ca740db5cdc9416d2a345ca9619b3','00003b00dbdcdc9416d2a345ca961907','!!!/!!#/!!$/'),(NULL,'04003c88db5e3304d6a102d5ca961913','00003c88db5e3304d6a102d5ca96192a','!!!/!!#/!!$/'),(NULL,'4affb00cdbbf0f800e3dfb651f9619a0','0000450cdbbf0f800e3dfb651f961973','!!!/!!#/!!$/'),(NULL,NULL,'00005634dbd11fc4e9737a9e0f961988','!!!/!!#/!!$/'),(NULL,NULL,'00005634dbd11fc4e9737a9e0f9619ce','!!!/!!#/!!$/'),(NULL,NULL,'00005634dbd11fc4e9737a9e0f9619d7','!!!/!!#/!!$/'),(NULL,NULL,'00005784dbc49b00852c7a9e0f96198a','!!!/!!#/!!$/'),(NULL,NULL,'00005bc1dbcdd7042d1efb651f961978','!!!/!!#/!!$/'),(NULL,NULL,'0000637b6f37c24013568e4c2c3ee4d6','!!!/!!#/!!$/'),(NULL,'080069db0f858240a2c9982be1050eae','000069db0f858240a2c9982be1050eb2','!!!/!!#/!!$/'),(NULL,'f98e3bb21b155c10a59033f2cd4bcbef','00006c47db5d9010d82ffb24399619d8','!!!/!!!/#YZ/'),(NULL,NULL,'00006c50db6a0450d58ea345ca961972','!!!/!!#/!!$/'),(NULL,NULL,'00006e38dbc19304032a7a9e0f9619e4','!!!/!!#/!!$/'),(NULL,NULL,'00006edddbec8c5813b5fb24399619b9','!!!/!!#/!!$/'),(NULL,NULL,'000073fedb41fb041cd8a345ca961934','!!!/!!#/!!$/'),(NULL,NULL,'000073fedb41fb041cd8a345ca96195c','!!!/!!#/!!$/'),(NULL,'d03c6ee61b774410a59033f2cd4bcbf5','000076bfdbb74c981cd8a345ca9619ee','!!!/!!!/!;B/'),(NULL,NULL,'000076ecdbde48502be0a851ca9619dd','!!!/!!#/!!$/'),(NULL,NULL,'000076ecdbde48502be0a851ca9619fe','!!!/!!#/!!$/'),(NULL,NULL,'0000778d6fd01a4000270bae9f3ee4ff','!!!/!!#/!!$/'),(NULL,NULL,'000077c21b3fbb0cada243f6fe4bcba7','!!!/!!#/!!$/'),(NULL,NULL,'000077c21b3fbb0cada243f6fe4bcbcb','!!!/!!#/!!$/'),(NULL,'f6c5f2110f75de401c7e938172050e1b','000077e10f7d5e00e59b982be1050e62','!!!/!!#/!!$/'),(NULL,NULL,'00007fa76ff70a0000270bae9f3ee4b1','!!!/!!#/!!$/'),(NULL,'73ff6fe76f4761007ceff7307f3ee478','00007fe76f4761007ceff7307f3ee47c','!!!/!!#/!!$/'),(NULL,'a4d63f4bdb8fbf00414ed0c5ca96191d','0000881b1b8f7f00fff162c4bd4bcbe7','!!!/!!!/$)(/'),(NULL,'a4d63f4bdb8fbf00414ed0c5ca96191d','0000881b1b8f7f00fff162c4bd4bcbec','!!!/!!!/$)(/'),(NULL,NULL,'000094eb6f781a0099c5409e9f3ee48e','!!!/!!#/!!$/'),(NULL,NULL,'000094eb6f781a0099c5409e9f3ee493','!!!/!!#/!!$/'),(NULL,'401fb78cdb18d8dc1cd8a345ca9619c8','00009c10dbdc98dcfeb1a851ca96192f','!!!/!!!/$$8/'),(NULL,'9dd30a24db5c1cdc23f4a345ca96192b','00009e2cdb1c589c4819fb243996195c','!!!/!!#/!!$/');
35+
36+
DROP TABLE IF EXISTS `task`;
37+
CREATE TABLE `task` (
38+
`parent` varchar(32) DEFAULT NULL,
39+
`sys_id` char(32) NOT NULL DEFAULT '',
40+
`sys_domain_path` varchar(255) DEFAULT NULL,
41+
PRIMARY KEY (`sys_id`),
42+
KEY `task_parent` (`parent`),
43+
KEY `sys_class_name_2` (`sys_domain_path`),
44+
KEY `sys_domain_path` (`sys_domain_path`)
45+
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
46+
47+
INSERT INTO `task` VALUES (NULL,'-1','!!!/!!#/!!$/'),(NULL,'00000195dbe7f30413b5fb2439961936','!!!/!!#/!!$/'),(NULL,'0000032edb160f04d7e37aa31f961964','!!!/!!#/!!$/'),('a6fe0637dbddfb8c1cd8a345ca96196f','000003dcdb31f3c0a39a0b55ca961916','!!!/!!#/!!$/'),('2f1df65d6fca3100e7f68e4c2c3ee4e6','000004466f127d40e7f68e4c2c3ee4ce','!!!/!!#/!!$/'),('50dfb42edbbdd3403eb27a9e0f96199e','0000056edbbdd3403eb27a9e0f961995','!!!/!!!/+0{/'),('5f5af922dbb804d03bf6a851ca961999','000006eedb7c04d03bf6a851ca96190c','!!!/!!!/$9;/'),(NULL,'00000904db1dd45014d6fb24399619b7','!!!/!!#/!!$/'),('33c6e522db2c10104ac3a851ca9619f3','00000a06dbf0181416d2a345ca96197b','!!!/!!#/!!$/'),(NULL,'00000ccd6f9196041501f7307f3ee406','!!!/!!#/!!$/'),(NULL,'00000ee2dbb9bf4014d6fb24399619a7','!!!/!!#/!!$/'),(NULL,'00000f065bba40000a4de1945e425441','!!!/!!#/!!$/'),(NULL,'000013dedbc0bf00bbc40b55ca961959','!!!/!!!/,*7/'),(NULL,'000016bcdb29009cf7fca851ca961927','!!!/!!#/!!$/'),(NULL,'0000171bdbdb770066e0a345ca96195a','!!!/!!!/+N?/'),('8eb9317f1b895450d01143f6fe4bcb26','00001c80db5d509022e0fb24399619ed','!!!/!!!/0RG/'),(NULL,'00001d84dbf6f2405a4af85e0f9619f9','!!!/!!#/!!$/'),(NULL,'00001e31db25d4105ed4a851ca96195c','!!!/!!#/!!$/'),(NULL,'00001ea3db73c89823f4a345ca9619b5','!!!/!!#/!!$/'),('c3baf3fadb234c54d82ffb24399619e0','00001f4fdbab4c542be0a851ca96190c','!!!/!!#/!!$/'),(NULL,'0000221bdbb4b3c466e0a345ca9619f0','!!!/!!!/$^{/'),(NULL,'000022bcdb9c04d022e0fb24399619e1','!!!/!!#/!!$/'),('9b7152434f995a80f347524e0210c7e0','0000234b6f59de00fbd4409e9f3ee446','/'),('c64ed870145461009a1c80cd6740d192','00002434145461009a1c80cd6740d1e5','!!!/!!#/!!$/'),(NULL,'0000247edb84d7040e3dfb651f9619b2','!!!/!!#/!!$/'),(NULL,'000025f8dbb6ba007fc27c541f96195b','!!!/!!#/!!$/'),('9b691033485d95c0c5abf6bd15eef576','0000287348dd95c0c5abf6bd15eef572','!!!/!!#/!!$/'),('3c4f591edb7ce2406015f47e0f96191b','00002952dbbce2406015f47e0f961999','!!!/!!!/#MU/'),(NULL,'000029b0db6d5c104819fb24399619a8','!!!/!!#/!!$/'),(NULL,'00002a3d1b5f0010a59033f2cd4bcb90','!!!/!!!/&<#/'),(NULL,'00002a9fdb5787840e3dfb651f9619a6','!!!/!!#/!!$/'),(NULL,'00002c5adb5a0fc0d7e37aa31f9619ba','!!!/!!#/!!$/'),('fa753886dbd8181014d6fb2439961989','00002d5edbdc949466e0a345ca9619e4','!!!/!!!/$44/'),('56ff56bfdb469c503fa35583ca961987','00002e73db0a9c50364a5583ca961922','!!!/!!#/!!$/'),(NULL,'000031f6dba76b40c9c302d5ca9619c4','!!!/!!#/!!$/'),(NULL,'000036fadb1a0344d7e37aa31f96196d','!!!/!!#/!!$/'),(NULL,'000036ffdb046744d58ea345ca961937','!!!/!!#/!!$/'),(NULL,'000037c2dbaae700fb115583ca961926','!!!/!!#/!!$/'),(NULL,'000038eedbe32380b1b102d5ca9619c9','!!!/!!!/#2J/'),(NULL,'00003925dbb1c300225d7aa31f961993','!!!/!!#/!!$/'),('58c865acdb2944184ac3a851ca961901','0000392cdbe944184ac3a851ca9619ea','!!!/!!!/(*S/'),(NULL,'00003966db307a800e58fb651f9619a7','!!!/!!!/&C[/'),('bdeae17bdbfed3045ed4a851ca961933','0000397bdbb217045ed4a851ca96192e','!!!/!!#/!!$/'),('1b951202dbbe7b8014d6fb2439961926','00003a02db767f80fec4fb243996198f','!!!/!!!/#*L/'),(NULL,'00003e5bdbe33b8416d2a345ca961919','!!!/!!#/!!$/'),(NULL,'00003eef1b0a4410fff162c4bd4bcb0e','!!!/!!#/!!$/'),(NULL,'000040b6dbcfcb000e58fb651f9619d2','!!!/!!#/!!$/'),(NULL,'000040e5db0a185011762183ca9619c5','!!!/!!#/!!$/'),('101abff70ff99200a2c9982be1050ee7','000044c86f4a120000270bae9f3ee475','/'),('15d6f3c8dbb3ab0023f4a345ca9619ee','000045f2db5f2700f2eb02d5ca9619c6','!!!/!!!/#*./');
48+
49+
ANALYZE TABLE sysapproval_approver PERSISTENT FOR COLUMNS() INDEXES();
50+
ANALYZE TABLE task PERSISTENT FOR COLUMNS() INDEXES();
51+
52+
--enable_warnings
53+
--enable_result_log
54+
--enable_query_log
55+
56+
set optimizer_use_condition_selectivity=4;
57+
58+
explain format= json SELECT sysapproval_approver0.`sys_id` FROM ((sysapproval_approver sysapproval_approver0 INNER JOIN task task1 ON sysapproval_approver0.`sysapproval` = task1.`sys_id` AND ((task1.`sys_domain_path` = '/' OR task1.`sys_domain_path` LIKE '!!!/!!#/!!$/%' OR task1.`sys_domain_path` LIKE '!!!/!!!/%'))) INNER JOIN task task2 ON task1.`parent` = task2.`sys_id` AND ((task2.`sys_domain_path` = '/' OR task2.`sys_domain_path` LIKE '!!!/!!#/!!$/%' OR task2.`sys_domain_path` LIKE '!!!/!!!/%'))) WHERE task2.`sys_id` LIKE '8e7792a7dbfffb00fff8a345ca961934%' AND (sysapproval_approver0.`sys_domain_path` = '/' OR sysapproval_approver0.`sys_domain_path` LIKE '!!!/!!#/!!$/%' OR sysapproval_approver0.`sys_domain_path` LIKE '!!!/!!!/%') ORDER BY sysapproval_approver0.`order` LIMIT 0, 50;
59+
60+
--disable_query_log
61+
--disable_result_log
62+
--disable_warnings
63+
64+
drop database mdev25830;
65+
66+
--enable_warnings
67+
--enable_result_log
68+
--enable_query_log
69+
70+
set global innodb_stats_persistent= @innodb_stats_persistent_save;
71+
set global innodb_stats_persistent_sample_pages=
72+
@innodb_stats_persistent_sample_pages_save;

‎mysql-test/main/opt_trace.result‎

Lines changed: 2 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -2093,18 +2093,7 @@ explain select * from t1 where a=1 and b=2 order by c limit 1 {
20932093
"selectivity_from_index": 0.021
20942094
}
20952095
],
2096-
"selectivity_for_columns": [
2097-
{
2098-
"column_name": "a",
2099-
"ranges": ["1 <= a <= 1"],
2100-
"selectivity_from_histogram": 0.1797
2101-
},
2102-
{
2103-
"column_name": "b",
2104-
"ranges": ["2 <= b <= 2"],
2105-
"selectivity_from_histogram": 0.0156
2106-
}
2107-
],
2096+
"selectivity_for_columns": [],
21082097
"cond_selectivity": 0.021
21092098
}
21102099
]
@@ -3314,18 +3303,7 @@ explain select * from t1 where pk = 2 and a=5 and b=1 {
33143303
"selectivity_from_index": 0.1
33153304
}
33163305
],
3317-
"selectivity_for_columns": [
3318-
{
3319-
"column_name": "a",
3320-
"ranges": ["5 <= a <= 5"],
3321-
"selectivity_from_histogram": 0.1
3322-
},
3323-
{
3324-
"column_name": "b",
3325-
"ranges": ["1 <= b <= 1"],
3326-
"selectivity_from_histogram": 0.1
3327-
}
3328-
],
3306+
"selectivity_for_columns": [],
33293307
"cond_selectivity": 0.1
33303308
}
33313309
]

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