Re: performance of parsing docbook with xincludes

On May 15, 2018, at 21:56 , Stefan Sauer <[email protected]> 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