Question

我们已将MySql 5.7数据库的副本迁移到Amazon RDS上的MySql 8.0.11。如果可能，所有内容都相同。包含几何数据的表已被修改，因此几何列被限制为SRID 0，并且重建了空间索引。两个数据库的执行计划是相同的，并表明查询正在使用空间索引。

在MySql 5.7上，以下查询在MySql 8上花费0.001s，在108s上花费。在MySql 8上，查看执行统计信息“发送数据”的时间占100％。

No index = foo
[0] = foo
[1] = bar
The value is: foo bar
The value is now: bar

我们有许多不同的空间查询，并且所有查询的行为都与此类似，但是特别是MBRINTERSECTS和ST_INTERSECTS似乎非常慢。更改为ST_CONTAINS（在可能的情况下）可以带来显着的改进（即，上面的过程用3s而不是108s），但这不适用于许多查询，并且仍然比5.7慢很多。

SELECT r.roadid                             
FROM geocoder.osm_road r
WHERE mbrintersects(ST_Buffer(ST_GEOMETRYFROMTEXT('Point(-1.91289 52.58260)',0),0.0005), r.geometry)

从osm_road显示索引（5.7）

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

从osm_road显示索引（8.0.11）

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,,

显示全局状态（8.0.11）Click Here

显示全局变量（8.0.11）Click Here

-添加了2019-01-27 -----------------

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

返回：

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);

Answer 1

MBRIntersects和ST_Intersects在MySQL 8.0（在8.0.15中进行测试）中已损坏，与MySQL 5.7相比，运行速度慢了10倍以上。对于我来说，禁止使用空间索引（使用IGNORE INDEX，强制执行全表扫描，可以在某种程度上加快我的查询速度。请参见此错误报告https://bugs.mysql.com/bug.php?id=94655

Answer 2

我也遇到类似的问题，答案是确保空间列包含SRID。参见https://mysqlserverteam.com/upgrading-to-mysql-8-0-with-spatial-data/。完成之后，查询开始使用空间索引，这是他们以前没有的

MySql 8.0.11空间查询速度降低了100000

2 个答案: