Back in January 2010, I wrote an article titled Proxy Trace : Tracing the Variables and Functions Available within MySQL Proxy.

That post was basically a lua script I posted which traces the steps of Proxy, outputting comments as it traverses through the various functions, and then outputs the names and values of [most of] the available variables available within Proxy.

That script worked fine with Proxy 0.7.2 and 0.8.0. It also works just fine with Proxy 0.8.1 (though you need to specify your admin settings in 0.8.1) and 0.8.2 (admin values not necessary).

However, I did go ahead and build it out a little further.

I did not add too much, but I did add the following (the full script, trace.lua, is provided at the end of this post):

• Outputs backends.type variable
• Expanded the rows returned outputs (returns more detailed row …

Have you ever wanted a handy reference of all of the various variables available in MySQL Proxy?

I’ve written a Lua script that outputs many of the available variables, which is really useful for coding Lua scripts for MySQL Proxy. In addition to the variables, it also generates output during each main function it enters in the Proxy, so you can follow the execution trace, and then see the value of each variable when it is within a particular function.

I’ve tested this on MySQL Proxy 0.7.2 and the newly available Proxy 0.8.0.

Here is a sample of the output, where I just connect, and then issue a simple query (SELECT * FROM world.city LIMIT 1):

C:Program FilesMySQLmysql-proxy-0.8.0bin>mysql-proxy.exe
 --proxy-lua-script=show-vars.lua

/* Entering function connect_server() */
   When the proxy accepts a connection from a MySQL …