Last weekend I started a shell that is based on the core libs of the MySQL Proxy and now code is good enough to be really useful.
As the shell is internally driven with a lua-script it is very easy to change the display or the way how the result of a query is processed. A simple feature that comes to mind is appending a SHOW WARNINGSwhenever query resulted in warning.
root@127.0.0.1:3306 []> create table t2 ( id serial ) engine = foo;
OK (warnings: 2, auto-commit: true, affected rows: 0, insert-id: 0)
+---------+------+--------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------+
| Warning | 1286 | Unknown table engine 'foo' |
| Warning | 1266 | Using storage engine MyISAM for table 't2' |
+---------+------+--------------------------------------------+
OK (warnings: 0, auto-commit: true)
This automaticly makes EXPLAIN EXTENDED a lot more useful as we see how it rewrites our queries:
root@127.0.0.1:3306 []> EXPLAIN EXTENDED SELECT (SELECT 1);
+----+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+
| 1 | PRIMARY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used |
+----+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+
OK (warnings: 2, auto-commit: true)
+-------+------+------------------------------------------+
| Level | Code | Message |
+-------+------+------------------------------------------+
| Note | 1249 | Select 2 was reduced during optimization |
| Note | 1003 | SELECT 1 AS `(SELECT 1)` |
+-------+------+------------------------------------------+
OK (warnings: 0, auto-commit: true)
Comments