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 并重建了空间索引。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。查看执行统计“发送数据”在 MySql 8 上占 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，并且所有的行为都是这样的，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(即上面的代码需要 3 秒而不是 108 秒)，但这并不适合许多查询，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 (5.7) 的索引

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) Click Here

显示全局变量 (8.0.11) Click Here

-- 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); 

返回:

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

最佳答案

MBRIntersects 和 ST_Intersects 在 MySQL 8.0(在 8.0.15 中测试)中被破坏并且与 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，强制进行全表扫描，稍微加快了我的查询速度。请参阅此错误报告 https://bugs.mysql.com/bug.php?id=94655

关于MySql 8.0.11 空间查询慢了 100000 倍，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/53819582/