Saxon has supported the StAX interface for pull parsing for a while now, but I've seen little evidence that people are using it; and in fact generally the scene seems to have gone rather quiet. There's talk that a future JAXP release will require support for StAX as well as SAX input, and on .NET the standard System.Xml parser is a pull parser, so I thought I'd take a look at relative performance - perhaps the time might even come when it's appropriate to use a StAX parser as the default.
I wrote a little program to build a Saxon tree using various parsers: two pull and two push. These were the results, all timings in milliseconds:
Input size (Mb) Xerces Piccolo SJSXP Woodstox
6.8 1200 1320 1270 1030
14.0 2400 2670 2640 2033Xerces and Piccolo are SAX (push) parsers; SJSXP and Woodstox are StAX (pull) parsers. So there's certainly no reason from these figures (or from any other considerations really) to believe that pull is intrinsically faster than push. But it's interesting (a) that Woodstock does appear to have a demonstrable edge (20%) on all the others at least on this sample -- one would have to test a variety of other XML documents to be sure that it's sustainable, and (b) that Piccolo doesn't beat Xerces in this test, though they claim to be twice as fast in other tests.
I'm not recommending that everyone switches over immediately to Woodstox - as often happens, they seem to have achieved some of the speed by taking short cuts on conformance, especially checking the detailed rules for valid names and valid characters. But if the 20% matters to you and you know the XML is valid already, it may be worth considering.