[Dbix-class] Why is prefetch so slow?

[Jon Schutz]

On Thu, 2007-10-18 at 19:38 +0100, Matt S Trout wrote:
> On Thu, Oct 18, 2007 at 03:03:24PM +0930, Jon Schutz wrote:
> > 
> > According to the bug report above, the problem should be fixed in RPM
> > perl-5.8.8-22 and later, so I compiled and installed perl-5.8.8-24 and
> > re-ran Nigel's benchmark.  The results show that the patched patched
> > version in 5.8.8-24 is still about 2-4 as slow with/without my patch to
> > ResultSourceHandle.  This compares against 8-12 times slower with
> > perl-5.8.8-10.
> 
> Would you concur that in that case this doesn't justify modifying DBIx::Class'
> code to compensate?

Yes.

> 
> Do you reckon a warning or just a note in the documentation is in order to
> warn people using broken RH perls to compile their own for best performance?
> 

I would strongly support a warning sent to stderr on startup, which
could be turned off by setting an environment variable, e.g.
DBIC_IM_SICK_OF_THAT_WARNING=1.

To outline the ramifications that this problem had for us would be
tedious, so let's just say that the several days that I spent isolating
the issue out of our wider system, plus all the support provided by
Nigel and others on IRC, is only a fraction of the impact.

Adding a note to the documentation would of course be sensible, but
insufficient by itself.

Thanks everyone for your various levels of support on this.

-- 

Jon