Yes, but the issue remains present if you have to deal with a high
number of map tasks to distribute the load on many machines.
Launching a
JVM is costly, let's say it costs 1 second (i'm optimistic) , if you
have to do 2000 map, there will be 2000 seconds lost in launching
JVMs...
Executing users' code in system daemons is a security risk. In my
experience, security always wins in when pitted against performance.
IMHO, there is a happy middle ground, i.e. to maintain a pool of
running JVMs that are launched when the tasktracker starts up. Even
then, care has to be taken against memory leaks etc.
- Milind
--
Milind Bhandarkar
(mailto:[EMAIL PROTECTED])
(phone: 408-349-2136 W)
