I made some improvements to the 'proxy' inside of MySQL 5.7 that I've created for WarpSQL (Shard-Query 3).  I've made the MySQL proxy/shim pluggable and I moved the SQLClient to sql/sql_client.cc.  I've merged these changes into 'master' in my fork.

Now you can create "SQL shim" plugins (SHOW PASSWORD is implemented in plugin/sql_shim) and install them in the server like regular plugins:

-- command doesn't work
mysql> show password;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'password' at line 1

-- install the example sql_shim plugin:
mysql> install plugin sql_shim soname 'sql_shim.so';                                                                 Query OK, 0 rows affected (0.00 sec)

-- now the command works
mysql> show password;
+--+
|  |
+--+
|  |
+--+
1 row in set (0.00 sec)

…

I made some improvements to the 'proxy' inside of MySQL 5.7 that I've created for WarpSQL (Shard-Query 3).  I've made the MySQL proxy/shim pluggable and I moved the SQLClient to sql/sql_client.cc.  I've merged these changes into 'master' in my fork.

Now you can create "SQL shim" plugins (SHOW PASSWORD is implemented in plugin/sql_shim) and install them in the server like regular plugins:

-- command doesn't work
mysql> show password;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'password' at line 1

-- install the example sql_shim plugin:
mysql> install plugin sql_shim soname 'sql_shim.so';                                                                 Query OK, 0 rows affected (0.00 sec)

-- now the command works
mysql> show password;
+--+
|  |
+--+
|  |
+--+
1 row in set (0.00 sec)

…

[this is a repost of my http://shardquery.com blog post, because it did not syndicate to planet.mysql.com]

As work on WarpSQL (Shard-Query 3) progresses, it has outgrown MySQL proxy.  MySQL proxy is a very useful tool, but it requires LUA scripting, and it is an external daemon that needs to be maintained.  The MySQL proxy module for Shard-Query works well, but to make WarpSQL into a real distributed transaction coordinator, moving the proxy logic inside of the server makes more sense.

The main benefit of MySQL proxy is that it allows a script to "inject" queries between the client and server, intercepting the results and possibly sending back new results to the client.  I would like similar functionality, but inside of the server.

For example, I would like to implement new SHOW commands, and these commands do not need to be …

[this is a repost of my http://shardquery.com blog post, because it did not syndicate to planet.mysql.com]

As work on WarpSQL (Shard-Query 3) progresses, it has outgrown MySQL proxy.  MySQL proxy is a very useful tool, but it requires LUA scripting, and it is an external daemon that needs to be maintained.  The MySQL proxy module for Shard-Query works well, but to make WarpSQL into a real distributed transaction coordinator, moving the proxy logic inside of the server makes more sense.

The main benefit of MySQL proxy is that it allows a script to "inject" queries between the client and server, intercepting the results and possibly sending back new results to the client.  I would like similar functionality, but inside of the server.

For example, I would like to implement new SHOW commands, and these commands do not need to be …