Greetings Almost 4 years to the day of the first commits toying with the idea, the constructor rewrite / prefetch modernization project seems to be nearing completion. At least it passes enough tests to be deemed a CPAN experimental release candidate, which *should not* eat your data.
So what is in this release? - First the notable parts of the changelog: * New Features / Changes - Rewrite from scratch the result constructor codepath - many bugfixes and performance improvements (the current codebase is now capable of outperforming both DBIx::DataModel and Rose::DB::Object on some workloads). Some notable benefits: - Multiple has_many prefetch - Partial prefetch - you now can select only columns you are interested in, while preserving the collapse functionality (collapse is now exposed as a first-class API attribute) - Prefetch of resultsets with arbitrary order (RT#54949, RT#74024, RT#74584) - Prefetch no longer inserts right-side table order_by clauses (massively helps the deficient MySQL optimizer) - Massively optimize codepath around ->cursor(), over 10x speedup on some iterating workloads. Yes, you are reading this right - in addition to many of the structural improvements DBIC now is pretty damn fast. All while maintaining 100% backwards compatibility our users have grown to expect. Some numbers on non-threaded perl 5.16.2 (DBI: 1.623, DBD::SQLite: 1.37, RDBO: 0.804, DBIx::DM: 2.31 ) - Laurent Dami's benchmarks  from his talk at FPW2012  Numbers before (DBIC 0.08206): http://paste.debian.net/plain/234081 Numbers after (DBIC 0.08240-TRIAL): http://paste.debian.net/plain/234080 - A *part* of the RDBO benchmark suite (svn) (DBIC needs further optimizations to win more of these benchmarks): Numbers before (DBIC 0.08206): http://paste.debian.net/plain/234083 Numbers after (DBIC 0.08240-TRIAL): http://paste.debian.net/plain/234082 Pretty damn good I must say. Also keep in mind that none of this requires any changes to your code. In fact if something works with 0.08206 but *does not* function under 0.08240 - this is a bug and it needs to be fixed before we go for GA. Speed is good - but what about these new features? From here on you get more fine-grained control over your selection. Prefetch is now a thin wrapper around join/+columns/collapse, and while you can use it like you did before you no longer have to. Instead you can do things like this , or this . You should receive the result you would otherwise assemble manually, but much much faster. And random order works too, just as described in . The changeset is massive, and does not easily yield to review. This is why the dev team needs your help - PLEASE TEST THIS RELEASE. Really test it stress it and bend it. Complain if a result doesn't match your expectations. Complain if the performance seems to take a nosedive on a specific workload. Whatever you are unhappy with - let us know. If despite all warnings you want to subject your eyes to the workhorse behind these improvements - check out  (but you have been warned :)) A thing to note is that the *really gnarly* code assemblers are all nicely tucked behind an interface  with minimal dependency on DBIC. In other words the collapser generator is ready to be extracted as a standalone CPAN offering (the DBIC dev-team would like this *very* much). So that should be in for now - please give it a try and let us know where/how we screwed things up. And if you are rather happy with what you see - we can always use a ++ on metacpan ;P Cheers  Proof that benchmarking against walltime is a very bad idea ;)  https://github.com/damil/compare-ORM  http://lists.scsys.co.uk/pipermail/dbix-class/2012-July/010595.html  https://www.youtube.com/watch?v=7NmJfuN3vUc  https://rose.googlecode.com/svn/trunk/modules/Rose-DB-Object/t/benchmarks/  https://metacpan.org/module/RIBASUSHI/DBIx-Class-0.08240-TRIAL/lib/DBIx/Class/ResultSet.pm#prefetch  https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08240-TRIAL/t/prefetch/manual.t#L46  https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08240-TRIAL/t/prefetch/manual.t#L226  http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits/DBIx-Class.git;a=commit;h=fcf32d045  https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08240-TRIAL/lib/DBIx/Class/ResultSource/RowParser/Util.pm  https://metacpan.org/source/RIBASUSHI/DBIx-Class-0.08240-TRIAL/lib/DBIx/Class/ResultSource/RowParser.pm#L71 _______________________________________________ List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class IRC: irc.perl.org#dbix-class SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ Searchable Archive: http://email@example.com