What's the max number of characters I can store in a JSON column in MySQL? I don't see this mentioned in the MySQL manual.
解决方案
Here's a demo of what @JorgeLondoño is talking about.
Set the server's max allowed packet size:
mysql> set global max_allowed_packet=1024*1024*1024;
Exit and open the mysql client again, this time setting the client max packet size to match:
$ mysql --max-allowed-packet=$((1024*1024*1024*))
Create a test table with a JSON column and fill it with the longest JSON document you can:
mysql> create table test.jtest ( j json );
mysql> insert into test.jtest
set j = concat('[', repeat('"word",', 100000000), '"word"]');
Query OK, 1 row affected (1 min 49.67 sec)
mysql> select length(j) from test.jtest;
+-----------+
| length(j) |
+-----------+
| 800000008 |
+-----------+
This shows that I was able to create a single JSON document with 100 million elements, and MySQL stores this in approximately 800MB.
I didn't try a longer document. I assume it maxes out at 1 GB, which is the largest value you can set for max_allowed_packet.