Re: DateTime performance

On Thursday 03 May 2012 02:14:45 you wrote:
> > From: Philipp K. Janert [mailto:[email protected]]
> > Sent: Wednesday, 2 May 2012 8:29 AM
> > 
> > Question:
> > 
> > When using DateTime for a large number of
> > instances, it becomes a serious performance
> > drag.
> 
> ...
> 
> > Is this expected behavior? And are there access
> > patterns that I can use to mitigate this effect?
> > (I tried to supply a time_zone explicitly, but that
> > does not seem to improve things significantly.)
> 
> Hi Phillip,
> 
> My #1 tip is to pre-prepare/cache the DateTime::TimeZone object and pass it
> in to each creation of a DateTime object (via whatever mechanism you're
> using to do that). I have seen a case where we were using time_zone =>
> 'local' in a reasonably tight datetime object creation loop and saw
> significant speed increases just by cutting out that chunk of processing.
> 
> In hindsight that was a silly thing to do but it became an easy win :-)
> 
> I apologise if this is what you meant by supplying a time_zone explicitly
> in your comment above.

I have tried to specify the timezone explicitly as a string:
  $dt = DateTime->new( ..., time_zone => "America/Chicago" )
which does not seem to help, but I have not tried to do:
  $tz = DateTime::TimeZone( 'America/Chicago' )
  $dt = DateTime->new( ..., time_zone => $tz )

I'll try that the next time I have to process one of my data
sets again. ;-)

Thanks for the hint.

> 
> I can't recommend using a tool like NYTProf highly enough on a run of your
> tool to spot the low hanging fruit. See
> https://metacpan.org/module/Devel::NYTProf
> 
> Cheers,
> 
> Andrew