Tag: python

GDB 7!

I wasn’t prepared for this. After spending months playing with GDB development trees I somehow entirely missed that 7.0 release is getting close, and took me more than an hour to spot it.

My favorite features are python scripting and non-stop debugging. I was toying around with python scripting for a while, and was planning to make backtraces make sense. Having hands that open means that one can see PHP backtraces, when gdb’ing apache, see table names and states when MySQL thread access handler interfaces, or remote IPs and users, when it is writing to network. Process inspection can simply rock, if right tools are created using these new capabilities, and I’m way too excited when I think about those. “Always have debugging symbols” gets way more meaning now.

Another issue I’ve been trying to resolve lately is avoiding long locking periods for running processes (directly attaching to process can freeze its work for a second or so, which isn’t that tolerable in production environments). GDB is getting closer to the async debugging capabilities – where one can run a debugger without actually stopping anything.

So, congratulations GDB team, now it is job for us to find all the uses of the tool. It has been invaluable so far, but this is much much more.

MySQL DBA, python edition

In the age of jetsetting and space travel and ORMs and such, MySQL DBAs are the least sophisticated ones nowadays, usually fighting terabytes or petabytes of data with army of shell scripts – as there’re no nice frameworks to explain what you want to do in MySQL administration. The nice thing about proper object frameworks is that they allow to concentrate on the work and logic done, allowing to think on the process done, rather on languages/APIs/etc.

For example, moving a slave to another master down a replication topology could be expressed this way (this is a working code, actually):

slave = mysql(options.slave)
oldmaster = mysql(slave.get_master())
newmaster = mysql(options.newmaster)

oldmaster.lock()
oldpos = oldmaster.pos()
newmaster.wait(oldpos)
newmaster.lock()
oldmaster.unlock()
slave.wait(oldpos)
slave.change_master(newmaster)
newmaster.unlock()

I’m sure transaction group/global IDs would simplify the process a lot, but still, having building blocks one can write pretty much self-documenting narrow code, shuffle actions done without having to rethink whole programming logic too much. Implementation of methods like .sync(), .clone(), .promote() ends up environment-specific, but may save quite some time afterwards too.

As much as I’d like everyone around to get their data management actions written down into scripts, I’d like every DBA action I do to be written down in such code too :-) I’d love to have code, which detects resource shortages, orders servers, deploys software and re-shards data automatically… well, you know what I mean :)