[Dbix-class] [ANNOUNCE] A much faster DBIx::Class 0.08250 is now on CPAN

[Peter Rabbitson]

After a long and fascinating journey DBIx::Class version 0.08250 [1] is 
finally here. Not much has entered the changelog [2] since the first 
trial announcement [3], but a great deal of oversights have been fixed 
and extra optimizations have taken place. To recap: if you upgrade from 
an older version of DBIC to the current 0.08250 you will:

- Not need to change any of your existing code. The undertaking to clean 
  up and streamline the internals was always centered around the premise 
  that the spice must flow. If something seems to be working differently – 
  please do file a bugreport.

- Observe a massive speed-up of iterating codepaths - places where you do
  while (my $r = $rs->next) { ... }

- Finally be able to truly reap the benefits of prefetching [4]. Up 
  until now a combination of several factors could turn this feature from 
  an optimization to a massive time-waster, especially on large 
  resultsets. No more – the current codepath performs equally well on 
  resultsets containing either 5 or 500,000 individual results.

- Notice that DBIx::Class::ResultClass::HashRefInflator [5] is now twice 
  as fast. The new internals allow for intelligent bypassing of much of 
  the result construction machinery when all you need is a hash.

- Be able to specify exactly which columns you wish to prefetch, instead 
  of the old "all or nothing" approach. Future blogposts will likely 
  explore this improvement in detail, but this test case should be a 
  decent primer for what is currently possible: observe what is returned 
  [6] given this fixture [7] and these search criteria [8]. The only thing 
  that is new API is the collapse() attribute [9], everything else behaves 
  exactly as you expect.

- And as shown in the above examples you will finaly be able to perform 
  any combination of same level has_many prefetches, and perform 
  prefetches fom resultsets with any arbitrary order_by (including 
  RANDOM() ).


As customary – here are some numbers from 3rd party benchmark suites
comparing the current 0.08250 (right) with the previous stable 0.08210 
(left).

 - Laurent Dami's benchmark taken from https://github.com/damil/compare-ORM
   (git 5782179afd): http://www.diffchecker.com/v89swf0a

 - John Siracusa's benchmark taken from
   http://rose.googlecode.com/svn/trunk/modules/Rose-DB-Object/t/benchmarks
   (svn rev 2274): http://www.diffchecker.com/6uzm88b5

I also would like to thank folks who helped along the way with code, 
documentation, ideas, and plain old prodding. In particular:

abraxxa - Alexander Hartmaier
Caelum - Rafael Kitover
castaway - Jess Robinson
frew - Arthur Schmidt
ldami - Laurent Dami
mattp - Matt Phillips
mna
mo - Moritz Onken
mst - Matt Trout
rkinyon - Rob Kinyon
SineSwiper - Brendan Byrd

And likely others I can not currently remember. Thank you all! This code 
would not have materialized without your help.


So this is it. Take it for a spin and let us know what we missed. In the 
meantime the next yak awaits ;)

Cheers and happy search()ing \o/

[1] https://metacpan.org/release/RIBASUSHI/DBIx-Class-0.08250/
[2] https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08250/Changes#L4
[3] http://lists.scsys.co.uk/pipermail/dbix-class/2013-February/011109.html
[4] https://metacpan.org/module/DBIx::Class::ResultSet#PREFETCHING
[5] https://metacpan.org/module/RIBASUSHI/DBIx-Class-0.08250/lib/DBIx/Class/Manual/Cookbook.pod#Skip-result-object-creation-for-faster-results
[6] https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08250/t/prefetch/manual.t#L338
[7] https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08250/t/prefetch/manual.t#L15
[8] https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08250/t/prefetch/manual.t#L223
[9] https://metacpan.org/module/DBIx::Class::ResultSet#collapse