Michael Haardt's randomized retry stuff, using the new letter "H".

5 files changed, 34 insertions, 10 deletions

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 3f2121c1c..c3d1fe70a 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -1,4 +1,4 @@
-$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.235 2005/09/19 09:41:37 fanf2 Exp $
+$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.236 2005/09/19 11:56:11 ph10 Exp $
 
 Change log file for Exim from version 4.21
 -------------------------------------------
@@ -207,6 +207,9 @@ TF/06 The fix for widen_domains has also been applied to qualify_single and
       search_parents which are the other dnslookup options that can cause
       header rewrites.
 
+PH/49 Michael Haardt's randomized retrying, but as a separate retry parameter
+      type ("H").
+
 
 Exim version 4.52
 -----------------
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index cd69ef60e..4640547ae 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -1,4 +1,4 @@
-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.71 2005/09/15 12:22:41 fanf2 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.72 2005/09/19 11:56:11 ph10 Exp $
 
 New Features in Exim
 --------------------
@@ -155,6 +155,16 @@ TF/01 There's a new script in util/ratelimit.pl which extracts sending
       rates from log files, to assist with choosing appropriate settings
       when deploying the ratelimit ACL condition.
 
+PH/13 A new letter, "H", is available in retry parameter sets. It is similar
+      to "G" (geometric increasing time intervals), except that the interval
+      before the next retry is randomized. Each time, the previous interval is
+      multiplied by the factor in order to get a maximum for the next interval.
+      The mininum interval is the first argument of the parameter, and an
+      actual interval is chosen randomly between them. Such a rule has been
+      found to be helpful in cluster configurations when all the members of the
+      cluster restart at once, and may synchronize their queue processing
+      times.
+
 
 Exim version 4.52
 -----------------
diff --git a/src/ACKNOWLEDGMENTS b/src/ACKNOWLEDGMENTS
index 238b52d2a..9b60b6f30 100644
--- a/src/ACKNOWLEDGMENTS
+++ b/src/ACKNOWLEDGMENTS
@@ -1,4 +1,4 @@
-$Cambridge: exim/src/ACKNOWLEDGMENTS,v 1.34 2005/09/12 13:50:03 ph10 Exp $
+$Cambridge: exim/src/ACKNOWLEDGMENTS,v 1.35 2005/09/19 11:56:11 ph10 Exp $
 
 EXIM ACKNOWLEDGEMENTS
 
@@ -20,7 +20,7 @@ relatively small patches.
 Philip Hazel
 
 Lists created: 20 November 2002
-Last updated:  12 September 2005
+Last updated:  19 September 2005
 
 
 THE OLD LIST
@@ -146,6 +146,7 @@ Michael Haardt            Tidies to make the code stricter
                             continued maintenance of same
                           Patch for faster sort algorithm in queue.c
                           Patch for LDAP timeout handling
+                            ... and several more
 Thomas Hager              Patch for saslauthd crash bug
 Richard Hall              Fix for file descriptor leak in redirection
 Steve Haslam              Lots of stuff, including
diff --git a/src/src/readconf.c b/src/src/readconf.c
index 220438ada..3ceece489 100644
--- a/src/src/readconf.c
+++ b/src/src/readconf.c
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/src/src/readconf.c,v 1.12 2005/08/08 10:48:27 ph10 Exp $ */
+/* $Cambridge: exim/src/src/readconf.c,v 1.13 2005/09/19 11:56:11 ph10 Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
@@ -3554,6 +3554,7 @@ while ((p = get_config_line()) != NULL)
       break;
 
       case 'G':   /* Geometrically increasing intervals */
+      case 'H':   /* Ditto, but with randomness */
       rule->p1 = retry_arg(&p, 0);
       rule->p2 = retry_arg(&p, 1);
       break;
@@ -3564,7 +3565,7 @@ while ((p = get_config_line()) != NULL)
       }
 
     if (rule->timeout <= 0 || rule->p1 <= 0 ||
-          (rule->rule == 'G' && rule->p2 < 1000))
+          (rule->rule != 'F' && rule->p2 < 1000))
       log_write(0, LOG_PANIC_DIE|LOG_CONFIG_IN,
         "bad parameters for retry rule");
 
diff --git a/src/src/retry.c b/src/src/retry.c
index 2e743a793..5126e5344 100644
--- a/src/src/retry.c
+++ b/src/src/retry.c
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/src/src/retry.c,v 1.3 2005/06/29 14:17:01 ph10 Exp $ */
+/* $Cambridge: exim/src/src/retry.c,v 1.4 2005/09/19 11:56:11 ph10 Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
@@ -739,15 +739,24 @@ for (i = 0; i < 3; i++)
         if (rule == NULL) next_try = now; else
           {
           if (rule->rule == 'F') next_try = now + rule->p1;
-          else  /* assume rule = 'G' */
+          else  /* rule = 'G' or 'H' */
             {
             int last_predicted_gap =
               retry_record->next_try - retry_record->last_try;
             int last_actual_gap = now - retry_record->last_try;
             int lastgap = (last_predicted_gap < last_actual_gap)?
               last_predicted_gap : last_actual_gap;
-            next_try = now + ((lastgap < rule->p1)? rule->p1 :
-               (lastgap * rule->p2)/1000);
+            int next_gap = (lastgap * rule->p2)/1000;
+            if (rule->rule == 'G')
+              {
+              next_try = now + ((lastgap < rule->p1)? rule->p1 : next_gap);
+              }
+            else  /* The 'H' rule */
+              {
+              next_try = now + rule->p1;
+              if (next_gap > rule->p1)
+                next_try += random_number(next_gap - rule->p1);
+              }
             }
           }