Mike Kay summarized and reviewed the symposium and added his own observations. He was a little surprised that there was nothing about Binary XML and little about speeding up XSLT or XQuery. Kay made the following main points:
Performance against other objective:
- Saxon: first standard conformance, then usability, then performance
- performance is not always the most important consideration
- David Wheeler (invented the subroutine)- “Optimize the code that users actually write”.
- Should you optimize for Joe User or the expert?
Performance metrics:
- Response time / latency
- throughout
- resource cost
- scaleability
- Jim Robinson: “Good enough for us” -- your own requirements, not the world’s best solution
Performance methodology:
- measure
- understand - figure out where bottlenecks are and what can be done to improve it
- focus on critical components
- improve -but if not, don’t leave in the things that didn’t help
- repeat until ok - what counts as ok
Where are the bottlenecks?
- application-level glue
- parsing vs. query?
- validation?
- conversion to/from XML?
- serialization?
- query/transformation?
- too many phases in the pipeline?
What improvements can we expect?
- faster parsing has ben promised?
- faster and more scalable transformation
- optimized pipelines?
- smarter users?
- faster hardware
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