mysql - MySql 8.0.11 空间查询慢了 100000 倍
问题描述
我们已将 MySql 5.7 数据库的副本迁移到 Amazon RDS 上的 MySql 8.0.11。在可能的情况下,一切都是相同的。包含几何数据的表已被修改,因此几何列被限制为 SRID 0 并重建空间索引。两个数据库上的执行计划相同,表明查询正在使用空间索引。
在 MySql 5.7 上,以下查询需要 0.001 秒,在 MySql 8 上需要 108 秒。在 MySql 8 上查看执行统计信息“发送数据”占 100% 的时间。为什么?
SELECT r.roadid
FROM geocoder.osm_road r
WHERE mbrintersects(ST_Buffer(ST_GEOMETRYFROMTEXT('Point(-1.91289 52.58260)',0),0.0005), r.geometry)
我们有许多不同的空间查询,并且都表现得像这样,但特别是 MBRINTERSECTS 和 ST_INTERSECTS 似乎非常慢。更改为 ST_CONTAINS(在可能的情况下)会带来显着的改进(即上面需要 3 秒而不是 108 秒),但这不适用于许多查询,并且仍然比 5.7 慢很多。
Show Create Table for 5.7
CREATE TABLE `osm_road` (
`roadid` bigint(20) NOT NULL,
`reference` varchar(20) DEFAULT NULL,
`name` varchar(100) DEFAULT NULL,
`dictionary` longtext,
`road_speed_limit` tinyint(4) unsigned NOT NULL,
`road_speed_unitid` tinyint(1) NOT NULL,
`road_type` tinyint(4) NOT NULL,
`is_toll_road` bit(1) NOT NULL DEFAULT b'0',
`is_one_way` bit(1) NOT NULL DEFAULT b'0',
`countryid` smallint(6) DEFAULT NULL,
`geometry` geometry NOT NULL,
`datemodified` datetime DEFAULT CURRENT_TIMESTAMP,
`datecreated` datetime DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`roadid`),
UNIQUE KEY `id_roadid` (`roadid`),
SPATIAL KEY `ix_road_geometry` (`geometry`),
KEY `ix_road_reference` (`reference`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AVG_ROW_LENGTH=207
Show Create Table for 8.0.11
CREATE TABLE `osm_road` (
`roadid` bigint(20) NOT NULL,
`reference` varchar(20) DEFAULT NULL,
`name` varchar(100) DEFAULT NULL,
`dictionary` longtext,
`road_speed_limit` tinyint(4) unsigned NOT NULL,
`road_speed_unitid` tinyint(1) NOT NULL,
`road_type` tinyint(4) NOT NULL,
`is_toll_road` bit(1) NOT NULL DEFAULT b'0',
`is_one_way` bit(1) NOT NULL DEFAULT b'0',
`countryid` smallint(6) DEFAULT NULL,
`geometry` geometry NOT NULL /*!80003 SRID 0 */,
`datemodified` datetime DEFAULT CURRENT_TIMESTAMP,
`datecreated` datetime DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`roadid`),
UNIQUE KEY `id_roadid` (`roadid`),
KEY `ix_road_reference` (`reference`),
SPATIAL KEY `ix_road_geometry` (`geometry`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AVG_ROW_LENGTH=207
显示来自 osm_road 的索引 (5.7)
Table,Non_unique,Key_name,Seq_in_index,Column_name,Collation,Cardinality,Sub_part,Packed,Null,Index_type,Comment,Index_comment
osm_road,0,PRIMARY,1,roadid,A,18973144,NULL,NULL,,BTREE,,
osm_road,1,ix_road_geometry,1,geometry,A,18973154,32,NULL,,SPATIAL,,
osm_road,1,ix_road_reference,1,reference,A,199900,NULL,NULL,YES,BTREE,,
显示来自 osm_road (8.0.11) 的索引
Table,Non_unique,Key_name,Seq_in_index,Column_name,Collation,Cardinality,Sub_part,Packed,Null,Index_type,Comment,Index_comment,Visible
osm_road,0,PRIMARY,1,roadid,A,16194921,NULL,NULL,,BTREE,,,YES
osm_road,1,ix_road_reference,1,reference,A,86215,NULL,NULL,YES,BTREE,,,YES
osm_road,1,ix_road_geometry,1,geometry,A,16194921,32,NULL,,SPATIAL,,,YES
显示全局状态 (8.0.11)点击这里
显示全局变量 (8.0.11)点击这里
-- 添加于 2019-01-27 -----------------
EXPLAIN SELECT r.roadid FROM geocoder.osm_road r WHERE mbrintersects(ST_Buffer(ST_GEOMETRYFROMTEXT('Point(-1.91289 52.58260)',0),0.0005), r.geometry);
回报:
select_type: Simple
table: r
partitions: null
possible_keys: ix_road_geometry
key: ix_road_geometry
key_len: 34
ref: null
rows: 1
filtered: 100
Extra: Using where
解决方案
MBRIntersects
并且ST_Intersects
在 MySQL 8.0 中被破坏(在 8.0.15 中测试)并且与 MySQL 5.7 相比慢了 10 倍以上。对我来说禁用空间索引(使用IGNORE INDEX
,强制全表扫描,在一定程度上加快了我的查询。请参阅此错误报告https://bugs.mysql.com/bug.php?id=94655