JMS slow for large TextMessages (3.0.6) plus a fix.

[hofhansl]

I did some throughput tests with JBossMQ and found a servere degradation with large TextMessages. Looking at SpyTextMessage.java I found that JBossMQ does chunking to work around a bug in JDK 1.3. This chunking is implemented in a way which always makes at least one copy of the entire string when reading *and* writing from/to the stream. In my case I removed the entire logic (I have JDK 1.4), but it is very easy to rewrite the code to do chunking only if the size is > 64K and do not make a copy of the string otherwise. After the change the performance for large strings (20k chars) doubled and in addition the CPU usage dropped from 100% to 7% (in other words it is now IO bound). I can send a fix if somebody wants it, but is it really trivial to fix...

[adrian.brock]

Post a patch at
www.sf.net/projects/jboss

If you can include a check for 1.4 that would be
even better. Make use of the following class.

http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/jboss/jboss-common/src/main/org/jboss/util/platform/Java.java?annotate=1.1.2.2

Regards,
Adrian

[hchirino]

It might be good to make that a configurable option somehow. Think about the case where a 1.4 system is sending a message to a 1.3 system.

Regards,
Hiram