Re: [xml] Bug 133736 – Relax NG validation sometimes takes long

[Daniel Veillard <veillard redhat com>]

On Tue, Jul 17, 2007 at 01:35:37PM +0200, John Loutzenhiser wrote:
> 
>    Hello,
>    we would very much like to move to relaxng for validation of our xml's
>    in our middleware, but unfortunately we ran across this bug!
>    I can confirm the exponential blowup reported in this bug perfectly. A
>    document  with an element with 13 optional attributes takes ~2 seconds
>    to   validate,  way  too  long  considering  W3C  validation  using  a
>    semantically equivalant schema takes just a few milliseconds.
>    It  seems  the  number  of validation states undergoes blowup. I can't
>    pretend to really understand the problem, but there is a loop over all
>    states in the validation context at line 10461 in relaxng.c
>    where validate state gets called. With 13 optional attributes it tries
>    to  validate 8192 states, and this loop starts being a real drag. Take
>    it up to 14 and it tries AGAIN to validate 16,384 states.
>    We  love  libxml2,  and  we  love  relaxng,  but  this  bug  is a real
>    show-stopper.
>    Any news? Please, please let us know.

  Sounds like a bug, yes, but I had no time to try to address it at the
moment.

Daniel

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