[Dbix-class] Caching a resultset?

[Peter Rabbitson]

On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
> 
> I have a Catalyst app that very frequently (pretty much every request)
> requires several DBIC resultsets that return a small number of values,
> that very rarely change. I'm trying to cache this, so I can update the
> cache when the values change and not have to hit my DB a half-dozen
> times on every request for data that is effectively static.
> 
> Originally the relevant line was along the lines of:
> 
>   $c->stash->{subjects} = $c->model('WordsDB::Subject')->search();
> 
> I replaced this, following the C::P::Cache docs, with 
> 
>   unless ( $c->stash->{subjects} = $cache->get( 'subjects' ) ) {
>     $c->stash->{subjects} = 
>         $c->model('WordsDB::Subject')->search();
>     $cache->set( 'subject', $c->stash->{subjects} );
>   }
> 
> However, this dies (on a second run, when it's actually hitting the
> cache) with "undef error - Can't call method "select" on an undefined
> value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957".

This is a crappy error message. Please tell us which DBIC version are
you running exactly so that we can figure out what is on this line.

> So I'm assuming that I can't just stuff a RS into the cache and expect 
> it to work.

Things should just work, at least for Storable-based serialization. Need 
more details to diagnose this.