I saw the work you did in OEJB. This would be a HUGE help as well.
On Jun 14, 2007, at 9:44 AM, Rick McGuire wrote:
One thing that might be a useful first start would be something
similar to the "Hungry Exception" cleanup effort that was done with
openejb3. Basically, this just ensured that any place where an
exception gets thrown because of another caught exception that the
original exception was maintained as a cause. I've spend a lot of
time grumbling about situations where the original exception
information was thrown away, sometimes through multiple levels of
failure.
Rick
Matt Hogstrom wrote:
Lately I've been working with users in debugging various
application problems. Some of the problems are merely
configuration but others are deeper application / infrastructure
problems. Regardless of the type of problem I've never personally
been satisfied with the diagnostic information produced by the
server (this isn't a Geronimo statement but really AppServers as a
whole including WebSphere and WebLogic).
Here are some thoughts that I want to pursue:
I’ve been working with some customers lately and the work has
centered around debugging some of the aspects of their server. In
this case it was using Apache Geronimo but the problem really
applies to most application servers in general. For the most part
there is little diagnostic information available when an
application fails. We get the ever popular nested Java Stack
trace which is certainly a good indicator of where a failure
occurred but is woefully inadequate in many instances of why a
failure occurred. This get’s worse in that for the most part
people need to recreate the problem with additional tracing and,
in the worst case, additional diagnostic code in their
application. Wouldn’t it be nice if some of the diagnostic
capability that was needed was included in the server itself?
Over the next few weeks I’m going to be doing some experimentation
on how to improve server diagnostics through the use of Aspects
and/or Instrumentation. Since this is experimental we’ll see what
the final result will be. Here are some of my initial goals:
1. Improve diagnostics by providing a Diagnostic Report when a
Tx fails.
2. Provide better visualization of Java Stack traces so problem
areas pop out.
3. Capture wait information
For number 1 I’m going to focus on servlets to begin with given
that they represent the preponderance of requests made in
AppServers today. This information will include information from
the request object, the servlet being invoked, invocation time,
transaction ID (if it exists), enlisted connections (database and
messaging), oh yeah, and the Thread ID of execution. This is a
mouthful to begin with anyway.
Number 2 is really just applying some template information on a
Java Stack trace. I want application classes to standout so
developers will be able to quickly see where their application is
involved. Infrastructure pieces like the server, Hibernate,
TopLink, etc. would also be highlighted in a different color and
style and plain old java classes would be a boring style as their
are merely pawns in the transactional game.
Finally, wouldn’t it be nice to know how long a thread has been
waiting and for what reason? Is it waiting on a request from
another server or perhaps there is a database locking problem.
Did a WebService go awry? Basically, I want to know what in the
heck a thread is waiting on.
Please chime in with your thoughts. I spect that Aspects or
Instrumentation may be the only way to go for some of this as many
of the components we include won't have this capability in them.
