From 5718c66a2a64752b695dcccd2c9559d41b5981db Mon Sep 17 00:00:00 2001
From: Sacha Greif <sacha357@gmail.com>
Date: Sun, 23 Dec 2012 17:25:03 +0100
Subject: [PATCH] only run scoreUpdate if score difference is large enough

---
 server/scoring.js | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/server/scoring.js b/server/scoring.js
index 8703bd659..5de93a32c 100644
--- a/server/scoring.js
+++ b/server/scoring.js
@@ -5,18 +5,27 @@ var updateScore = function (collection, id) {
 
   // use baseScore if defined, if not just use the number of votes
   // note: for transition period, also use votes if there are more votes than baseScore
-  var baseScore = Math.max(object.votes || 0, object.baseScore || 0);
+  // var baseScore = Math.max(object.votes || 0, object.baseScore || 0);
+  var baseScore = object.baseScore;
 
   // now multiply by 'age' exponentiated
   // FIXME: timezones <-- set by server or is getTime() ok?
   var ageInHours = (new Date().getTime() - object.submitted) / (60 * 60 * 1000);
 
-  // HN algorithm (same as Bindle)
+  // HN algorithm
   var newScore = baseScore / Math.pow(ageInHours + 2, 1.3);
 
-  collection.update(id, {$set: {score: newScore}});
+  // Note: before the first time updateScore runs on a new item, its score will be at 0
+  var scoreDiff = Math.abs(object.score - newScore);
 
-  // console.log('old score: '+object.baseScore+' | new score: '+newScore+' | score diff: '+Math.abs(newScore-object.baseScore));
+  // console.log('updating score | scoreDiff:'+scoreDiff);
+
+  // only update database if difference is larger than a given value to avoid extra work
+  if (scoreDiff > 0.00001){
+    collection.update(id, {$set: {score: newScore}});
+    return 1;
+  }
+  return 0;
 };
 
 Meteor.startup(function () {
@@ -24,9 +33,17 @@ Meteor.startup(function () {
   // recalculate scores every N seconds
   if(scoreInterval>0){
     intervalId=Meteor.setInterval(function () {
+      var updatedPosts = 0;
+      var updatedComments = 0;
       // console.log('tick ('+scoreInterval+')');
-      Posts.find().forEach(function (post) { updateScore(Posts, post._id); });
-      Comments.find().forEach(function (comment) { updateScore(Comments, comment._id); });
+      Posts.find().forEach(function (post) {
+        updatedPosts += updateScore(Posts, post._id);
+      });
+      Comments.find().forEach(function (comment) {
+        updatedComments += updateScore(Comments, comment._id);
+      });
+      console.log("Updated "+updatedPosts+"/"+Posts.find().count()+" Posts")
+      console.log("Updated "+updatedComments+"/"+Comments.find().count()+" Comments")
     }, scoreInterval * 1000);
   }
 });