[erlang-questions] xmerl still slow?

Erik Stenman <>
Wed Jan 31 16:44:46 CET 2007


Joel Reymont wrote:
>
> On Jan 31, 2007, at 1:32 PM, Erik Stenman wrote:
>
>> Are you saying ejabberd has a performance problem?
>
> I'm saying that they went with expat instead of xmerl for performance 
> reasons.
Are you sure? There are several reasons for going with expat instead of 
xmerl,
I am not sure that performance is the reason ejabberd uses expat.
More likely they wanted a finished fully implemented streaming xml-parser.
But I have no insight into the development of ejabberd so I don't know.

> It appears that performance mattered to them. According to you they 
> shouldn't be using XML but it's part of the XMPP protocol 
> specification :-).
I still say that if parsing XML takes to much time then there is 
something wrong with your protocol.
Too bad if the protocol is forced on you.
My experience is that you very seldom have to worry about Erlang 
performance.
Implement your application first. Then measure. Then use HiPE. Then worry.
You probably don't even have to measure because the prototype is fast 
enough.

/Erik





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