Python blogging software
Diez B. Roggisch
deets at nospam.web.de
Sun Sep 17 19:58:53 CEST 2006
> Fair enough. I shouldn't have said "lousy performance of the
> framework itself" when I should have included the application. If the
> application's page computations are so lengthy, then they too need
> speeding up.
> We've got a situation where some big sites (Slashdot, Wikipedia) have
> a lot of cached static pages for non-logged-in users (they all see the
> same thing), but any user who is logged in sees a version customized
> by their preferences, that's usually not cached. So there's a
> perverse incentive to not log in, since you see the static page
> I'd really like to get hold of a big active blog or BBS server to
> profile it. It's been puzzling me for years what makes them so slow.
> They just paste user-contributed content together with HTML from
> templates, so you'd think it shouldn't be too complicated.
Most of the time, that means fetching data from the DB, which means
context switches and network transfer. I'm a developer on a large
java-driven application that deals with books. The app benefits hugely
from caching - the whole object model is rather elaborated, and fetching
it into memory (including images stored as blobs), and serializing it
takes a couple of seconds. Per user! But just grabbing it from a disk as
html snippet speeds up the app tremendously.
Additionally, commercial sites often are composed by a rather large
number of different parts. Teasers, lists of e.g. thematically related
content and so on. And if you have lots of comparably large objects that
are very diverse, a larger number of users may mean to exhaust memory
quickly or even worse swap it around. All this is remedied by caching.
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