RE : [PATCH] FIFO file repository

[Diego Castillo <di...@inexbee.com>]

Hi Noel,

I do have a need for FIFO. I have been asking for such a feature for a
long time. You can check the thread "FIFO spool manager" on the user
mailing list (January 24, 2003).

I agree that the patch is ridiculous. I thought about making it
configurable via something like:
<config>
  <enforce-fifo>true</enforce-fifo> 
</config>

The default value could be false, so that no CPU time is spent unless
the user demands it.

However, I found that the simplest the change would be, the greater its
chances to get approved.

I do have tested its correct behaviour. With 1 spool thread, it is
perfectly FIFO.

I have also performed stress tests with the modification and have
experience no performance loss. My CPU intensive mailet application can
handle a durable load of 11 e-mail per second with the FIFO file
repository on dual Xeon 2.4GHz server. I was getting the same score
without the FIFO modification. However, I must admit that the
repositories are kept very small during my stress tests, so I can not
offer any figures of the CPU cost of sorting a long list. Sun claims to
have implemented the sorting algorithm in a n*log(n) manner.

Regards,


Diego

-----Message d'origine-----
De : Noel J. Bergman [mailto:noel@devtech.com] 
Envoyé : mardi 23 septembre 2003 20:40
À : server-dev@james.apache.org
Cc : Diego Castillo
Objet : RE: [PATCH] FIFO file repository

Diego,

I received the copy of the patch that you sent.  Yes, you have to be
subscribed to the mailing list, or your messages will require
moderation.

With respect to the patch, the only functional change is:

  +        Collections.sort(clone);

Have you been finding a problem?  In the event of very large
directories, I
don't know that we should spend the CPU that way if we don't have a
need.

	--- Noel

-----Original Message-----
From: Diego Castillo [mailto:diego.castillo@inexbee.com]
Sent: Monday, September 22, 2003 3:55
To: server-dev@james.apache.org
Cc: Diego Castillo, INEXBEE
Subject: [PATCH] FIFO file repository


Hi all,
Here goes a patch for enforcing FIFO ordering on file repositories.
Hopefully it will make it into version 2.2.0.
Regards,


Diego

--- AvalonMailRepository.java.orig	Wed Aug 06 09:41:56 2003
+++ AvalonMailRepository.java	Fri Sep 19 18:18:26 2003
@@ -431,12 +431,13 @@
      *
      */
     public Iterator list() {
-        // Fix ConcurrentModificationException by cloning
+        // Fix ConcurrentModificationException by cloning
         // the keyset before getting an iterator
-        final Collection clone;
+        final ArrayList clone;
         synchronized(keys) {
             clone = new ArrayList(keys);
         }
+        Collections.sort(clone);
         return clone.iterator();
     }
 }


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