giovedì 17 dicembre 2009

Is Groovy such terribly slow ?

A thing you hear often is that Groovy is not a good language because of its performances. Actually Groovy IS slow. Depending on the type of task, it can be from 10 - 15 times to 90 times slower than the equivalent Java version. And is usually much slower than Scala too. (By the way, Scala seems to be the hot language of the moment, what Groovy used to be 1 year ago...).
And the reason why Groovy is so slow is quite clear. To add all the metaprogramming magic, Groovy has to dispatch every method (even the ones that don't use metaprogramming) dynamically.
So, the best thing we can do is to stop using Groovy, go back to POF (Plain Old but Fast for those who love acronyms) Java and maybe start learning Scala...
There are a lot of reasons to keep using Groovy.
Performances are constantly improving at every new version. There is even an attempt to create a partially statically compiled version of Groovy (see the Groovy++ project). They are tryng to offer a better support to concurrency throught the introduction of the "Actors Pattern", present in languages like Scala and Erlang (see the GPars project). Maybe I will write a post on these two projects someday. So, there are a lot of efforts on this topic. And then there is a very important reason...the killer application of Groovy.
Of course Grails is based on Groovy, and extensively uses Groovy metaprogramming capabilities: so Grails performances are not so exciting. But it will take benefit from the improving performances of Groovy. And they are also working on big improvements on the performance side. As announced in the recent Groovy and Grails Exchange, (by the way, great event!) they are working on the precompilation of the GSP, maybe one of the biggest bottleneck in Grails. The number of request per second that Grails will handle in version 1.2 will double compared with older versions. And then, is the language speed so important when your application works with databases ? And with the network ? The weakest parts are others, not the language itself. With the current version (1.1), without GSP optimization , Grails performances are already comparable with the ones of other popular web frameworks (Tapestry, Wicket, Seam). But Grails is far mor productive than most of other frameworks.

So, is Groovy a slow language ? Yes, it is. If I want to develop an performance critical application with tons of business logic and number crunching, Groovy is not my first choice. But you shall not use the same tool for every job. (and yes, the language is a tool, even if a very important one, to build applications). For other kind of applications, the boost of productivity will overcome the performance issues. Do you remember what C++ developers were saying when Java came up ?

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