im using kdb+\q as well. I built a similar database in MySQL a while ago and the performance was pretty much unacceptable, although I did nothing to really tune it. kdb+ has been really fast for me so far, but the development is a lot slower just because q is so different from SQL, it's a vector oriented language and it's pretty interesting and well suited to my tasks for it, but for someone just learning like myself it's hard to use things that don't have big online communities, they do have a Google group which is pretty good though. It's 25k for the cheapest 64 bit version I believe, I just use the 32. I realize youre a professional, but obviously if you're having problems with your queries which you are reusing, you should build a class to create queries for you...you already knew that though. I'm also testing another column oriented dbms, monetDB at the suggestion of some folks on here. It's my understanding that column oriented is the way to go for tick data. Many people also recommend just writing and read binary files.
There are tons of sources for trading ideas and statistical techniques. Finding stuff that actually works is obviously the challenge. If you're brand new to this you probably know only a little less about trading than I do, but one thing that's really popular in quantitative trading is looking at relationships between timeseries instead of just single timeseries. Stationarity is the basis for a lot of the econometric techniques that apply to trading, so that's good to understand. There's all sorts of different stuff out there though, you can get a lot more in depth than investopedia just surfing random blogs, forums, research papers, interviews, free PDFs etc etc. that's where pretty much the entirety of my trading knowledge came from.