MySQL全文索引、联合索引、like查询、json查询速度哪个快

所属分类：数据库 / Mysql 阅读数： 184

收藏 0赞 0分享

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。