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From Kristian Waagan <kristian.waa...@oracle.com>
Subject Maven debug and source artifacts for Derby
Date Wed, 25 Apr 2012 16:02:50 GMT
Hi,

A few JIRAs have been logged where users are requesting that the Derby 
community provide debug artifacts for Maven (links at the end):
   o DERBY-5668: Derby does not publish source artifacts to Maven Central
   o DERBY-5543: include debug info in derby builds uploaded to maven
   o DERBY-3910: debug artifacts should be available in maven repositories

Regarding the source artifacts, I think we should just do it! Does 
anyone see a reason why we don't want to do it?

The debug artifacts requires a little more consideration. There are two 
requests at play here:
   a) include line numbers
   b) include the extra checks guarded by the SanityManager blocks
      (what's called a sane build)

I think many of the users would want to use artifacts (a). In fact I'd 
say they should probably be the default. I imagine artifacts (b) to be 
used during development and when you debug a problem. What we are 
currently proving is more along the lines of (c):
   c) reduced disk-footprint JARs for small devices

(a) and (c) are suitable for production, (b) isn't because of the 
performance degradation caused by the extra sanity checks.


A recent build of trunk shows the following increases in size when 
including line numbers [1]:
   o derby.jar: 2.6 MB -> 3.5 MB
   o derbyclient.jar: 523 KB -> 686 KB
   o derbynet.jar: 237 KB -> 302 KB

Not compiling away the extra checks only adds a little more. The growth 
is most significant for derby.jar, where it ends up at 3.7 MB.

They way I see it, adding line numbers has the following potential benefits:
   o make it easier for users to debug/investigate a problem where they 
get a stack trace
   o make it easier for the Derby community to start debugging a problem 
when they have a stack trace

The only downside I see is the increase in size. This probably isn't a 
big deal for most users, but I expect there will be some users that want 
to keep things as small as possible. As a note to this, there has been 
some speculation (?) that the increased size may slow down class 
loading. Again I assume this is a concern to only a subset of our users.

Together with source artifacts, I believe adding debug information will 
make it easier for people using Maven as their build tool to get 
involved with Derby. I think providing these artifacts can benefit both 
these users and the Derby community.
I can't see how providing these artifacts would hurt.

What do others think?


Links to the issues mentioned:
https://issues.apache.org/jira/browse/DERBY-5668
https://issues.apache.org/jira/browse/DERBY-5543
https://issues.apache.org/jira/browse/DERBY-3910


Regards,
-- 
Kristian

[1] We're only specifying debug=true, which I assume has the same effect 
as debug=on. This again I'm assuming causes -g to be passed to the 
compiler, since we're not specifying debuglevel, and -g means all debug 
information (-g:lines,vars,source).

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