Forum: Ruby Multithread in DRb

Suppose I want to create 6 threads in client side
following: http://segment7.net/projects/ruby/drb/introduction.html

which one is better at cleint side?
===
require 'drb'

DRb.start_service
remote_array = DRbObject.new nil, ARGV.shift

for i in 1..6
children[i]=Thread.New do
     remote_array << 1
     ----do other things
end

--rest of the program
=====
OR
====
require 'drb'

for i in 1..6
children[i]=Thread.New do
     DRb.start_service
     remote_array = DRbObject.new nil, ARGV.shift
     remote_array << 1
     ----do other things
end

--rest of the program
====

To point out whats in my mind, in the later program I am getting a new
instance of the remote object, so it will not have any resource
conflict.

What do you feel? 1st one or second one is better? AND WHY?

ajay paswan wrote in post #1078978:
> Suppose I want to create 6 threads in client side
> following: http://segment7.net/projects/ruby/drb/introduction.html
>
> which one is better at cleint side?

The second appears to be broken:

1. It calls DRb.start_service 6 times
2. It calls ARGV.shift 6 times - unless your intention is to have 6 
different DRB URLs, so that you are talking to six *diffferent* remote 
arrays, and push one item onto each? Then that's something completely 
different.

> To point out whats in my mind, in the later program I am getting a new
> instance of the remote object, so it will not have any resource
> conflict.

DRb gives absolutely zero locking. If two clients make concurrent 
accesses to the same remote object, then they will cause concurrent 
method calls to execute at the server side. Tthat is, your server object 
*must* be thread-safe.

It does not matter if you make one local proxy object and invoke it from 
six threads, or six separate proxy objects onto the same remote object 
invoked from six threads.

DRb is effectively transparent to all this. If your program works 
correctly with six local threads accessing a single local object 
concurrently, then it will be fine with six threads accessing a single 
remote object over DRb.

> Then that's something completely
> different.
why? and how?

please see my post: http://www.ruby-forum.com/topic/4406522#new

I am in a problem where a thread becomes locked, all other threads are 
working fine which does not have to create a new browser, else it 
stucks.

I have no clue how to solve this issue.
Kindly help.

ajay paswan wrote in post #1078981:
>> Then that's something completely
>> different.
> why? and how?

The second code you put consumes 6 elements from ARGV. You might be 
passing the same URL 6 times, or you might be passing 6 different URLs 
pointing to 6 different remote objects.

One array is different to 6 separate arrays.

> please see my post: http://www.ruby-forum.com/topic/4406522#new

and how does that relate to DRb?

> I am in a problem where a thread becomes locked, all other threads are
> working fine which does not have to create a new browser, else it
> stucks.

It seems you are talking to a Watir object; I have no idea if one of 
those is thread-safe or not.