I've got an ... interesting ... result on my hands.
I've been experimenting with feeding an application (Xalan) directly from
an XNI stream rather than from a SAX stream. The experimental code's
basically just doing a conversion from XNI to SAX and calling my normal SAX
handlers... plus a bit of additional hacking about if we happen to find a
PSVI annotation.
With schema validation turned off, performance of the XNI setup is
comparable to that of the SAX version -- as expected, since my XNI-to-SAX
conversion is probably very similar to what you folks do.
HOWEVER -- when I turn on the schema validator, parser performance falls
through the floor -- even though none of the test documents references a
schema, and only two of them reference a DTD. The parse() operation takes
almost twice as long to complete.
JProbe calls out the following as accounting for most of the difference.
The measurement is how much fasterr NON-schema-validated is versus
shema-validated, and includes all methods called by the named method. I
haven't attempted to sort them into who-calls-who order, though I suspec
the time sort actually comes pretty close to achieving that. (Apologies in
advance if this doesn't line up nicely on your screen; try a fixed-pitch
font.)
Cumulative time
StandardParserConfiguration.parse(boolean) -169872 (-48.7%)
XMLDocumentFragmentScannerImpl.scanDocument(boolean) -167192 (-48.4%)
XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(boolean)
-167182 (-48.4%)
XMLNamespaceBinder.handleStartElement(QName, XMLAttributes, Augmentations,
boolean)
-112707 (-67.2%)
XMLDocumentFragmentScannerImpl.scanStartElement() -112687 (-59.3%)
XMLDTDValidator.startElement(QName, XMLAttributes, Augmentations)
-112335 (-65.1%)
XMLNamespaceBinder.startElement(QName, XMLAttributes, Augmentations)
-112305 (-66.8%)
Is this a known issue (possibly already patched)? Or have I botched the
parser configuration somehow?
If the answer is "yes, it's slow and we're working on it" or "we've
improved in in the current CVS code", that's fine... but I thought I should
make sure you were aware of this, and ensure that it wasn't something
particularly stupid in my own code, before I proceeded to work on trying to
optimize my end of things.
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