There are lots of options for tracing web applications. But suppose you need a holistic view, such as a combined trace of the server-side Java and client-side JavaScript in an Ajax app. You might expect your options to drop to zero. Well, they don't. DTrace can handle it. The Mozilla DTrace Project provides DTrace probes for Firefox's JavaScript engine, and recent versions of the JVM have built-in probes. Amit's latest article shows how to put these together to trace an Ajax application. It produces a true end-to-end picture, with traces flowing across the client/server boundary.

How can a large project like GlassFish make such brisk strides on performance (1, 2, 3)? Well, for one thing, it certainly doesn't hurt to have backing from a company that has created tools like DTrace.

In his latest blog entry, Paul shows how he used DTrace to identify hot spots in the PostgreSQL JDBC Driver when run on GlassFish. Of course, the same techniques could be applied to any area of GlassFish. So please, feel free to jump in and help with our endless push for top performance.

Added: Also check out this Video Interview of the Dtrace tream.

Dick Davis (Rasputkin) is the author of Number 9 where he covers a number of topics, including hardware, Solaris and System Administration.

Dick had some reservations about J2EE but RoR on GF and the GF v2 beta contest encouraged him to give GlassFish a try and he seems to like it so far. Dick's first GF-related blog explains in detail how to start GlassFish on a Zone. Since then he wrote another good one, explaining how to Use DTrace on JVMs and applying this to GlassFish.

Solaris Zones and GlassFish mix well together. For example, the GlassFish Wiki just moved to its new location, a GlassFish instance on a Solaris Zone, and John has written quite a bit about GlassFish and Zones.