Automatically fill the page cache

Rails
1

Hi,

I have my whole site cached with page cache, because each page needs
some time to render. What I would like to do is to delete all files in
the cache (I have no problem with that). But after I have deleted
everything, I would like to cache each and every file again, so that my
visitors don’t experience any long load times. Any ideas on how to do
this the most efficiently. It’s a cache of more than 5.000 pages. Any
ideas are welcome. Thanks.

Kind regards,

Nick

2

Hi Nick,

Nick S. wrote:

…after I have deleted everything, I would like to cache each
and every file again, so that my visitors don’t experience any
long load times. Any ideas on how to do this the most efficiently.

As far as I know, the only way to get a page into the cache is to pull
it
there with a request from a client. OTOH, the client need not be a
browser. You could write a script that ‘computes’ all the possible
requests
(reflecting on controller methods) and then issues them (to the server
through the cache) using Ruby’s net/http library. It’s not elegant, and
there’re likely to be views that wouldn’t get rendered without making
your
script smarter, but it might not be a bad first step.

HTH,
Bill

3

Well, the web server (eg apache) wouldn’t have that much load, would
it? I bet 99% of the load will be in your app anyways.

In terms of traffic I would recommend a locally installed wget or curl
client just pulling everything. And in terms of cpu load: you could
run that script reniced(see “man nice”) level, so it doesn’t block
incoming requests.

This way your users might have to wait a bit while the page cache
slowly grows, and then you are back at hi speed.

Or else: create an identical instance on a second machine, have the
cache recreated there, copy everything off that machine onto your live
system.

/eno

====================================================================
A wee piece of ruby every monday: http://1rad.wordpress.com/

4

Hi Bill,

thanks for the reply. I already tought of this solution, but this would
mean hammering my own server for a while. Isn’t there a more elegant
way, so that the web server is not involved but that Rails handles the
cache generation.

Kind regards,

Nick