[Dbix-class] Caching a resultset?

[Jesse Sheidlower]

On Tue, Jan 15, 2013 at 01:30:55AM +1100, Peter Rabbitson wrote:
> 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". So I'm
> > assuming that I can't just stuff a RS into the cache and expect it to
> > work. Is there an easy way around it? (I know I could retrieve the
> > actual data and put that into the cache, but then I'd have to rewrite a
> > whole bunch of templates, that are expecting a resultset.)
> > 
> > Thanks.
> 
> So apart from the mystery around the nonsensical exception - does this help?
> 
> local $DBIx::Class::ResultSourceHandle::thaw_schema = $c->model(...)->schema;

Yes! Putting that before the "unless" seems to make everything work
correctly.... Will be testing further this afternoon. Thanks!

Does this need to be documented somewhere, or does something need to be
fixed, or...?

Jesse