Re: [xml] performance of parsing docbook with xincludes

[Nick Wellnhofer <wellnhofer aevum de>]

On May 15, 2018, at 21:56 , Stefan Sauer <ensonic hora-obscura de> wrote:
> On 05/15/2018 08:40 PM, Stefan Sauer wrote:
> > On 05/15/2018 12:42 PM, Nick Wellnhofer wrote:
> > > Can you try to change the line to
> > >
> > >     xmlCtxtUseOptions(pctxt, ctxt->parseFlags);
> > >
> > > and see if it helps?
> > It does not help. I'll experiment further. Thanks for the recomendations.

I think you also have to remove the line at https://git.gnome.org/browse/libxml2/tree/xinclude.c#n463

    pctxt->loadsubset |= XML_DETECT_IDS;

Looks like the idea is to make sure that ID attributes are detected for XIncludes with XPointers. IMO, it 
should be the application's responsibility to set the XML_PARSE_DTDLOAD flag in this case. But changing the 
behavior might break code that relies on this feature.

> Is libxml2 doing that for each file over and over?

Yes.

> Wouldn't it make sense to only load each dtd once?

This would make sense.

> And where exatly is it loaded (I can only
> see xmlFreeDtd, but can't find a xmlLoadDtd or the like.

Via xmlParseDocument -> xmlSAX2ExternalSubset -> xmlParseExternalSubset.

Nick