debug – code.openark.org

This is the 2nd sneak preview of common_schema‘s rdebug: debugger & debugging API for MySQL stored routines (see 1st preview here).

rdebug will be released as part of common_schema, free and open sourced.

In this sneak preview I present:

Compiling multiple routines with debug info
Starting/stopping a debug session
Step-over, step-in, step-out
Showing stack trace
Showing the next-statement to execute
Viewing and manipulating local routine variables
Misc. meta routines

The quick technical overview

rdebug is a server-side mechanism, itself written in MySQL stored routines. It manipulates your routines by injecting debug code (easily removed afterwards).

To debug a routine you will need two connections: one is the debugging connection, and the other is the worker connection. The debugger connection attaches itself to the worker connection, where your routines execute.

rdebug is controlled by an API of stored routines. This means any GUI tool may choose to use rdebug as its routine debugging mechanism. Your are not bound to a specific tool, a specific OS or framework. You may choose to invoke the API via command line, if you like; it’s all in your server.

A video is worth a thousand blogs Continue reading » “MySQL Stored Routines Debugger & Debugging API: sneak preview II, video”

This is a sneak peek video introduction/preview of an in-development free and open source server side debugger & debugging API for MySQL stored routines.

MySQL does not provide server side debugging capabilities for stored routines. Some tools exist, including MySQL’s own, that assist in stored routine debugging. These are all GUI based and, to the best of my knowledge, MS Windows based. There is one solution in alpha stage that is developed for Java/eclipse; I did not look at the code. See discussion here and here.

An ideal solution would be to have debugging API in the server itself – independently of your client, programming language or operating system. To the best of my knowledge, nothing like that is being developed.

I’m now presenting a rdebug: a stored routines server-side debugger, Pure-SQL, based on stored routines. rdebug is developed as part of common_schema, and actually relies on some of its power.

Like some other tools, it uses code injection and manipulation: it injects debugging info into your stored routine. You need to “compile” your routine with debugging info.

Unlike some other tools, it actually runs your stored routines. It does not mimic or simulate them on client side. It does not break them into smaller routines, attempting to assemble the original behavior from lego bricks.

The quick technical overview is that you use two processes (MySQL threads): the worker process running the routine (your natural call my_routine()), and the debugger process. The debugger process attaches itself to the worker process; it controls the worker by commands like “step over”; it gets data from the worker: what’s the current stack trace? What variables are now available and what are their values?; it manipulates the worker’s data: it can utilize breakpoints to modify worker’s local & session variables. Continue reading » “MySQL Stored Routines Debugger & Debugging API: sneak preview video”