maria-developers team mailing list archive

[Alexey Botchkov <holyfoot@xxxxxxxxxxxx>]

I ran an additional test - created a table in MySQL with the VARCHAR column,

not JSON (as i did in MariaDB), and ran the same query.

So now MySQL had to parse the JSON and then look for path there.

--------------------------------------------------

MySQL [test]> select count(*) from jt2 where json_extract(j, 
"$.key1[1].key2")='IT';
+----------+
| count(*) |
+----------+
| 20000000 |
+----------+
1 row in set (5 min 28.54 sec)

---------------------------------------------------

Wow, I was surprised. 5.5 minutes against 7.6 seconds.

That i guess answers two questions:

   how rapid is RapidJSON?

   why MySQL bothers with the new JSON field type?


Best regards.

HF




25.07.2016 14:10, Alexey Botchkov wrote:
> Hi, Sergei.
>
>
> I've requested your review on this, here are few additional notes.
>
> I ran some benchmarks comparing against MySQL5.7's JSON field type. 
> And it seems
>
> that the difference in performance is negligible.
>
> For instance here are results for 20M rows with rather complicated JSON:
>
>
> Space occupied:
>
> MariaDB
>
> -rw-rw----. 1 hf hf 9520000000 Jul 25 13:08 jt1.MYD
>
>
> MySQL
>
> -rw-r-----. 1 hf hf 9440000000 Jul 25 13:28 jt1.MYD
>
>
> Query time:
>
> MariaDB [test]> select count(*) from jt1 where json_extract(j, 
> "$.key1[1].key2")='IT';
> +----------+
> | count(*) |
> +----------+
> | 20000000 |
> +----------+
> 1 row in set (7.65 sec)
>
>
> MySQL [test]> select count(*) from jt1 where json_extract(j, 
> "$.key1[1].key2")='IT';
> +----------+
> | count(*) |
> +----------+
> | 20000000 |
> +----------+
> 1 row in set (7.56 sec)
>
>
> So again i can't think now of usecases where we have to store the JSON 
> in some special
>
> binary representation. Only thing i can figure out is that we'd like 
> to be able to read the MySQL database
>
> without any specific conversion.
>
>
> Best regards.
>
> HF