MySQL 5.7 对JSON的支持

文章由LinuxBoy分享于2019-03-31 06:03:14热评（357）

MySQL 5.7 对JSON的支持

最近有个业务需要能够存储Json并做一些简单的业务逻辑处理。业务找到我说json的数据分析很难用mysql 5.6 ,这样的纯粹行存来处理难度很大，问我有没啥办法。

我第一想到的是mongodb，第二想到的就是mysql 5.7 。然后一查，哎呀，已经GA了。众所周知的，mongodb的引擎层的稳定性一直是短板，而innodb经过10年的验证，已经是非常稳定的东西了。所以就在想，是不是可以试试mysql 5.7 ，简单尝试，发现mysql 5.7 + DRDS ，完全不带mongoDB玩啊。。。看看我的简单功能测试： create table json_test ( uid int auto_increment,data json,primary key(uid))engine=innodb; 建库 mysql> insert into json_test values (NULL, '{"name":"name1","mobile":"15044447279","amount":400}'); Query OK, 1 row affected (0.01 sec) mysql> insert into json_test values (NULL, '{"name":"name1","mobile":"15044447279","amount":300}'); Query OK, 1 row affected (0.01 sec) mysql> insert into json_test values (NULL, '{"name":"name2","mobile":"15044447278","amount":300}'); Query OK, 1 row affected (0.01 sec) mysql> insert into json_test values (NULL, '{"name":"name3","mobile":"15044447277","amount":300}'); Query OK, 1 row affected (0.01 sec) 插入四条语句 mysql> select data from json_test; +-----------------------------------------------------------+ | data | +-----------------------------------------------------------+ | {"name": "name1", "amount": 400, "mobile": "15044447279"} | | {"name": "name1", "amount": 300, "mobile": "15044447279"} | | {"name": "name2", "amount": 300, "mobile": "15044447278"} | | {"name": "name3", "amount": 300, "mobile": "15044447277"} | +-----------------------------------------------------------+ 查询这四条json语句 mysql> select data->"$.name" as name ,sum(data->"$.amount") from json_test group by name; +---------+-----------------------+ | name | sum(data->"$.amount") | +---------+-----------------------+ | "name1" | 700 | | "name2" | 300 | | "name3" | 300 | +---------+-----------------------+ 做个group by sum 常见的统计操作 insert into json_test values (NULL, '{"mobile":"15044447277","amount":300}'); 插入一个不带name的数据，看看索引对空数据的兼容性情况。 mysql> ALTER TABLE json_test ADD user_name varchar(128) GENERATED ALWAYS AS (json_extract(data,'$.name')) VIRTUAL; Query OK, 0 rows affected (0.05 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> alter table json_test add index idx_username (user_name); Query OK, 0 rows affected (0.04 sec) Records: 0 Duplicates: 0 Warnings: 0 创建虚拟列并建立索引 mysql> select user_name,sum(data->"$.amount") from json_test where user_name = '"name1"'; +-----------+-----------------------+ | user_name | sum(data->"$.amount") | +-----------+-----------------------+ | "name1" | 700 | +-----------+-----------------------+ 查看符合某个user_name的数据的sum。 mysql> explain select user_name,sum(data->"$.amount") from json_test where user_name = '"name1"'; +----+-------------+-----------+------------+------+---------------+--------------+---------+-------+------+----------+-------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra | +----+-------------+-----------+------------+------+---------------+--------------+---------+-------+------+----------+-------+ | 1 | SIMPLE | json_test | NULL | ref | idx_username | idx_username | 131 | const | 2 | 100.00 | NULL | +----+-------------+-----------+------------+------+---------------+--------------+---------+-------+------+----------+-------+ 确认带索引数据走到了索引上 =========== 然后，这东西竟然还支持事务。。这个就牛逼大了。。 mysql> start transaction; Query OK, 0 rows affected (0.00 sec) 开启事务 mysql> select * from json_test; +-----+-------------------------------------------------------------------+-----------+ | uid | data | user_name | +-----+-------------------------------------------------------------------+-----------+ | 1 | {"name": "name1", "amount": 400, "mobile": "15044447279"} | "name1" | | 2 | {"name": "name1", "amount": 300, "mobile": "15044447279"} | "name1" | | 3 | {"name": "name2", "amount": 300, "mobile": "15044447278"} | "name2" | | 4 | {"name": "name3", "amount": 300, "mobile": "15044447277"} | "name3" | | 5 | {"amount": 300, "mobile": "15044447277"} | NULL | | 6 | {"amount": "300", "name”:”name2”,”mobile": "15044447278"} | NULL | +-----+-------------------------------------------------------------------+-----------+ 查看原表。 mysql> insert into json_test (uid,data) values (NULL, '{"name":"name1","mobile":"15044447279","amount":300}'); Query OK, 1 row affected (0.00 sec) 插入新数据 mysql> select * from json_test; +-----+-------------------------------------------------------------------+-----------+ | uid | data | user_name | +-----+-------------------------------------------------------------------+-----------+ | 1 | {"name": "name1", "amount": 400, "mobile": "15044447279"} | "name1" | | 2 | {"name": "name1", "amount": 300, "mobile": "15044447279"} | "name1" | | 3 | {"name": "name2", "amount": 300, "mobile": "15044447278"} | "name2" | | 4 | {"name": "name3", "amount": 300, "mobile": "15044447277"} | "name3" | | 5 | {"amount": 300, "mobile": "15044447277"} | NULL | | 6 | {"amount": "300", "name”:”name2”,”mobile": "15044447278"} | NULL | | 7 | {"name": "name1", "amount": 300, "mobile": "15044447279"} | "name1" | +-----+-------------------------------------------------------------------+-----------+ 7 rows in set (0.00 sec) 确认新数据 mysql> rollback; 回滚数据 mysql> select * from json_test; +-----+-------------------------------------------------------------------+-----------+ | uid | data | user_name | +-----+-------------------------------------------------------------------+-----------+ | 1 | {"name": "name1", "amount": 400, "mobile": "15044447279"} | "name1" | | 2 | {"name": "name1", "amount": 300, "mobile": "15044447279"} | "name1" | | 3 | {"name": "name2", "amount": 300, "mobile": "15044447278"} | "name2" | | 4 | {"name": "name3", "amount": 300, "mobile": "15044447277"} | "name3" | | 5 | {"amount": 300, "mobile": "15044447277"} | NULL | | 6 | {"amount": "300", "name”:”name2”,”mobile": "15044447278"} | NULL | +-----+-------------------------------------------------------------------+-----------+ 6 rows in set (0.00 sec) 对mysql 5.7 好感度*2啊。。卧槽。猜测一下虚拟列的做法： ALTER TABLE json_test ADD user_name varchar(128) GENERATED ALWAYS AS (json_extract(data,'$.name')) VIRTUAL; 应该写入的时候做一个trigger 每个json都运算json_extract(data,'$.name') ，然后写到一个新的不可修改的列里。这个就可以让原来的行存和文档有一个非常完美的结合，当业务变化大的时候，放到json里面，而当变化稳定下来，就迁移到行存里。完美。推荐！

[译]JSON数据范式化（normalizr）

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