[Dbix-class] Avoiding _prune_unused_joins

[Bob MacCallum]

(I'm using 0.08250)

I'll avoid a boring preamble and just ask if anyone could advise on
how to construct resultsets so that deep in the internals,
_prune_unused_joins isn't called?  (so as to save me some CPU cycles)

I have tried to read the code but I'm not really sure what $ident is holding.

Here's the query that is called most in my code:

  my $rs = $row->some_relation->search(
     {},
     { where => { rank => { '>' => 0 } },
       order_by => 'rank',
       prefetch => { type => { 'dbxref' => 'db' } } }
  );

Performance with the prefetch is slightly better than with no prefetch at all.
Appreciate any help!

many thanks,
Bob.