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Infinite loop running Mod_R/Rapache

5 messages · BJ, Bill Szkotnicki, Frank E Harrell Jr +2 more

BJ
# 
I installed mod_r according to the specifications, and have been trying 
to get the demo script to work correctly. I am running debian, the 
latest build of R, apache 2 with prefork mpm, and the latest mod_r. Is 
anyone else using this module successfully? I added:

LoadModule R_module mod_R.so
<Location /test/hello>
    SetHandler r-handler
    Rsource /var/www/html/test.R
    RreqHandler handler
</Location>

to my http.conf and

test.R in /var/www/html is:

handler<-function(r){
    apache.write(r,"<h1>Hello World!</h1>")
OK
}

When I start apache2, my /tmp directory fills with rtmp directories 
until memory is exausted. The first time it created 32,000 before I 
noticed. Does anyone have any idea as to what I could be doing wrong, or 
have a software configuration that works? Thank you for all of your 
help. ~BJ
Bill Szkotnicki
# 
Hello,

Recently I have been reading a lot of material about statistical modeling
using R. There seems to be conflicting opinions about what the best approach
is between the SAS community and the R community.
1) In R one might start with a model that has all possible effects of
interest in it and then simplify by eliminating/adding insignificant effects
using a stepwise procedure.
2) In SAS one may starts with a "reasonable" model and look at type 3 SS's
to test hypotheses and report LSMEANS. This can be done in R too I think.

Does anyone have current opinions about this? I know it's been discussed
before but I would be very interested in hearing about the advantages and
pitfalls of both approaches.

Bill
Frank E Harrell Jr
#
Bill Szkotnicki wrote:
You'll get lots of opinions about this.  Both R and SAS can be abused 
terribly, and both approaches you mentioned have major problems if you 
use P-values to specify models.  Better and more replicable results can 
be obtained using modern shrinkage methods and being more liberal with 
inclusion of variables, or by using Bayesian model averaging.

Note that LSMEANS and Type III tests are SAS concoctions and that if you 
have interactions in the model, type III tests have been criticized.  If 
there are no interactions, type Type III = Type II.

Frank Harrell
Jeffrey Horner
#
BJ wrote:
This is definitely an apache configuration problem. After responding to 
you privately about this issue, I got paranoid and checked the latest 
R/Apache code release (rapache-0.1.1) with the following debian packages:

apache2-common/unstable uptodate 2.0.55-4
apache2-utils/unstable uptodate 2.0.55-4
apache2-mpm-prefork/unstable uptodate 2.0.55-4
apache2-prefork-dev/unstable uptodate 2.0.55-4

I could not reproduce the behavior you are witnessing. Maybe you can 
send me (off-list) your /etc/apache2/apache2.conf, 
/etc/apache2/sites-enabled/* and  see if I can't help you troubleshoot.

But this bit of R creating a temp dir (for transient files?) needs to be 
handled more delicately in a server environment. I'm going to do some 
more digging in the R source... I hope I haven't made some glaringly 
wrong assumptions.