[LON-CAPA-admin] hang httpd processes

[Guy Albertelli II]

Hi Hon-Kie,

> Yesterday, for the second time, 2 httpd processes hanged and consume a lot 
> of resources. I am not sure what function cause it to hang though the first 
> time there is a strong correlation with the print (PRT) button on the 
> remote. (There were errors on the print page when printing as a student but 
> the same problems printed on the construction space did not give any error.)
> 
> Question: Is there some way for me to find out what cause the process to 
> hang? I hate to see this happen off hours just before the assignment is due.

Four ways

1) 
  a) note the PID of the rogue procceses
  b) goto http://yourservername/server-status/
    It should say what URL is being processed by that child

2)
  a)  note the PID of the rogue procceses
  b) goto /proc/PID/ 
  c) ls -la the fd directory, this will list all files the child has
     open from this you might be able to discern what is going on

3) 
  a) note PID
  b) attach gdb to the running process use gdb to debug what it is
     doing

4)
  a) note PID
  b) use strace to attach to the proccess
  c) from the log of system calls try to discren what it is trying to
     do


Let me know one way or another what you see going on.


(BTW in version 0.6 instructors can cause infinte loops that don't
time out by generating resources that have missing end tags, this will
be fixed in 0.6.1)

-- 
guy at albertelli.com          BM: n^20 t20 z20 qS 
Guy Albertelli -7-7-7-  O-
    No man is an isthmus.