[packagekit] Caching for APT backend (or how to get queries down to 0.5s)

[Richard Hughes]

On Wed, 2007-09-26 at 23:07 +0200, Tom Parker wrote:
> Richard Hughes wrote:
> > On Wed, 2007-09-26 at 20:27 +0200, Tom Parker wrote:
> >> Haven't had much time to play with PackageKit recently (little things 
> >> like a PhD thesis to complete keep getting in my way)
> > Dude, joking aside, complete the thesis first and hack on PackageKit
> > second. In the grand scheme of things the thesis is 5000% more
> 
> I'm in the "let's process lots of supervisor's comments" stage, with
> basically no coding, and using PackageKit to keep me from going nuts
> when I've spent several hours trying to figure out how to rewrite a
> block of text.

Cool. Been there. When you look at formulas and think "I could write
that in latex for fun" then you probably need a break.

> Besides, PackageKit, and especially this bit, is so 
> different from what I'm writing about (embedded systems where 4kb of RAM 
> is typical), it's a good way to keep my perspective about the wider 
> world of computing!

Sure, me also. At work I'm working on machines with 128K of SRAM and
doing clever things with 300Mhz worth of CPU. And then I go home to dual
core 2GHz and a proper debugger :-)

> >> Haven't pushed this yet, but can post the patch if any direct comments 
> >> on the code as opposed to comments on the idea come up.
> > 
> > The idea is very sound. Could you pls post the patch just for me to cast
> > my eye over please?
> 
> Attached.

Initially looks good (and very compact, well done!).

> This is rough early work at the moment (automagically rebuilds
> only if we can't find the table in the DB for example). Notable bugs 
> include the hacky way of detecting the rebuild (can do smarter things 
> with sqlite3_open_v2 without the create flag) and that description 
> fields are not fully filled in yet. Neither of these are hard to fix, 
> but I wanted to get a bit of discussion going on this now that I had it 
> in a place where I could talk about timings with at least some certainty.

Sure. Looks good. If you want you can merge this, as I'm a couple of
weeks off releasing 0.1.0, although it might be best merged when it
works.

Thanks,

Richard.