Re: Performance of Woodstox StAX vs Java SAX

For what it's worth, now that Woodstox also implements SAX interface (as of 3.2.0), it is possible to see what effects API might have on implementations. With Woodstox, access via SAX API is slightly slower (for trivial browse-through case), but difference is minor (5-10%). Conceptually SAX and StAX interfaces are both low-level, and although to implement StAX one has to retain more state (and therefore gets more complicated), there are also couple of more optimizations one can do, as more processing can be deferred on as-needed basis than with SAX. But these do not have major effect on most usage.

Personally I would like to think that the speed is because Woodstox was designed from beginning with specific API and functionality in mind (as opposed to having to add new things like namespaces after the fact), as well as due to performance having been one of the top priorities throughout development.

As to Java-vs-C, interestingly there is one fairly recent comparison:

http://www.xml.com/pub/a/2007/05/09/xml-parser-benchmarks-part-1.html

results of which seem in line with what I would expect. Fastest (?) C implementation is bit faster than Woodstox, roughly with same ratio as Woodstox is faster than Xerces/SAX. Woodstox was the fastest of Java alternatives.

I hope this helps,

-+ Tatu +-

ps. Just in case it's not obvious, ObDisclaimer is that as the author of Woodstox my opinions may be slightly biased. ;-)