Well, maybe not, but it handles key => value pairs now :P
What does it do?
It handles 5 basic query types:
mysql> INSERT "key" = "value";
Very simple, insert a key => value pair on a
proxy.global.dbtable, if there is already a value for that query, it will overwrite it.
mysql> SELECT "key";
It retrieves the value for the specified key.
mysql> DELETE "key";
Deletes the key => value pair from the lua table.
mysql> SELECT *;
It returns all the key=> value pairs.
It deletes all rows from the table.
This time I used the tokenizer to parse the queries, and I'm so glad I did. It is much easier and cleaner that writing regular expressions to match your queries.
I also wrote different functions to handle each statement. Which I call based on the tokens I find.
Looking at the script, you will find different ways of returning results back to the mysql client. Something that took me a while to figure out was, how to return an empty resulset, but with a number of affected rows, like what you get from an INSERT statement.
This is the answer:
function add( key, value )
-- We add the key value pair to the global table
proxy.global.db[key] = value
-- we return a nice "affected rows count"
proxy.response.type = proxy.MYSQLD_PACKET_OK
proxy.response.affected_rows = 1
proxy.response.insert_id = 0
If you call this function, you need to do so like this:
return add(tokens[i + 1]["text"], tokens[i + 3]["text"])
and not just like this:
add(tokens[i + 1]["text"], tokens[i + 3]["text"])
* Note the "return" there. Otherwise, you will not get the custom resulset on the client.
I also added the connect_server() function, which allows you to run the mysql proxy without any mysql server on the backend.
How do I use it?
Get the code from the MySQL Forge site, and save it as proxydb.lua
Then, start the MySQL Proxy like this:
You can then connect to the port 4040 using your mysql client and start sending queries. If you use any of the queries I showed before, the proxydb.lua script will handle them.
Yesterday I run some tests and I found that
- Having 3,908,492 entries
- Key length was about 11 characters
- Value length was about 17 characters
- MySQL Proxy process used 1.5GB of RAM
Who knows, maybe someone will use this script and let me know how it runs on a busy setup :).