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MySQL全文索引、联合索引、like查询、json查询速度哪个快

目录

    查询背景一、like查询二、json函数查询三、联合索引查询四、全文索引查询

查询背景

有一个表tmp_test_course大概有10万条记录,然后有个json字段叫outline,存了一对多关系(保存了多个编码,例如jy1577683381775)

我们需要在这10万条数据中检索特定类型的数据,目标总数据量:2931条

SELECT COUNT(*) FROM tmp_test_course WHERE `type`=5 AND del=2 AND is_leaf=1

我们在限定为上面类型的同时,还得包含下面任意一个编码(也就是OR查询)

jy1577683381775

jy1577683380808

jy1577683379178

jy1577683378676

jy1577683377617

jy1577683376672

jy1577683375903

jy1578385720787

jy1499916986208

jy1499917112460

jy1499917093400

jy1499917335579

jy1499917334770

jy1499917333339

jy1499917331557

jy1499917330833

jy1499917329615

jy1499917328496

jy1576922006950

jy1499916993558

jy1499916992308

jy1499917003454

jy1499917002952

下面分别列出4种方式查询outline字段,给出相应的查询时间和扫描行数

一、like查询

耗时248毫秒

SELECT * FROM tmp_test_course

WHERE `type`=5 AND del=2 AND is_leaf=1

AND (

outline like ‘%jy1577683381775%’

OR outline like ‘%jy1577683380808%’

OR outline like ‘%jy1577683379178%’

OR outline like ‘%jy1577683378676%’

OR outline like ‘%jy1577683377617%’

OR outline like ‘%jy1577683376672%’

OR outline like ‘%jy1577683375903%’

OR outline like ‘%jy1578385720787%’

OR outline like ‘%jy1499916986208%’

OR outline like ‘%jy1499917112460%’

OR outline like ‘%jy1499917093400%’

OR outline like ‘%jy1499917335579%’

OR outline like ‘%jy1499917334770%’

OR outline like ‘%jy1499917333339%’

OR outline like ‘%jy1499917331557%’

OR outline like ‘%jy1499917330833%’

OR outline like ‘%jy1499917329615%’

OR outline like ‘%jy1499917328496%’

OR outline like ‘%jy1576922006950%’

OR outline like ‘%jy1499916993558%’

OR outline like ‘%jy1499916992308%’

OR outline like ‘%jy1499917003454%’

OR outline like ‘%jy1499917002952%’

)

EXPLAIN分析结果如下,全表扫描


二、json函数查询

json官方函数

耗时196毫秒,速度稍微快了一点

SELECT * FROM tmp_test_course

WHERE `type`=5 AND del=2 AND is_leaf=1

AND

(

JSON_SEARCH(outline, ‘one’, ‘jy1577683381775’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1577683380808’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1577683379178’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1577683378676’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1577683377617’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1577683376672’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1577683375903’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1578385720787’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499916986208’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917112460’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917093400’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917335579’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917334770’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917333339’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917331557’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917330833’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917329615’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917328496’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1576922006950’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499916993558’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499916992308’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917003454’) IS NOT NULL OR

JSON_SEARCH(outline, ‘one’, ‘jy1499917002952’) IS NOT NULL  

)

EXPLAIN分析结果如下,还是全表扫描


三、联合索引查询

下面为该表建立一个联合索引(本来想建一个type-del-is_leaf-outline的索引,但是outline字段太长限制,所以只加type-del-is_leaf的联合索引

ALTER TABLE tmp_test_course ADD KEY `type-del-is_leaf` (`type`,`del`,`is_leaf`)加入索引后再执行like和json查询,明显提速。

like执行用了136毫秒,json查询用了82.6毫秒,由此可见针对json类型使用json函数查询比like快

EXPLAIN分析结果如下,两者查询扫描的行数都限定在了2931行


四、全文索引查询

因为全文索引只支持CHAR、VARCHAR和TEXT,我们需要把JSON字段定义改一下

ALTER TABLE tmp_test_course MODIFY `outline` VARCHAR(1024) NOT NULL DEFAULT ‘[]’添加全文索引

ALTER TABLE tmp_test_course ADD FULLTEXT INDEX outline (outline);现在再来用全文索引进行检索

SELECT * FROM tmp_test_course

WHERE `type`=5 AND del=2 AND is_leaf=1

AND

MATCH(outline) AGAINST (‘jy1577683381775 jy1577683380808 jy1577683379178 jy1577683378676 jy1577683377617 jy1577683376672 jy1577683375903 jy1578385720787 jy1499916986208 jy1499917112460 jy1499917093400 jy1499917335579 jy1499917334770 jy1499917333339 jy1499917331557 jy1499917330833 jy1499917329615 jy1499917328496 jy1576922006950 jy1499916993558 jy1499916992308 jy1499917003454 jy1499917002952’)耗时11.6毫秒,速度提升极其明显,可见全文索引的牛逼。

EXPLAIN分析结果如下,显示只扫描了一行

结论

以下是4种情况的执行结果

全文索引: 11.6ms

联合索引:82.6ms(json)、136ms(like)

json函数查询:196ms

like查询: 248ms

结论:全文索引 > 联合索引 > json函数查询 > like查询


数据量越大,全文索引速度越明显,就10万的量,查询速度大概比直接查询快了20倍左右,如果是百万或千万级别的表,提升差距会更加大,所以有条件还是老老实实用全文索引吧

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原创文章,作者:starterknow,如若转载,请注明出处:https://www.starterknow.com/116198.html

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