From 881eb373c5f846eba21b143838285722c2531b06 Mon Sep 17 00:00:00 2001
From: Sam <sam.saffron@gmail.com>
Date: Fri, 25 Nov 2016 12:33:10 +1100
Subject: [PATCH] improve performance of backfill avoid queuing more than 1
 backfill call

---
 app/assets/javascripts/discourse/models/post-stream.js.es6 | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/app/assets/javascripts/discourse/models/post-stream.js.es6 b/app/assets/javascripts/discourse/models/post-stream.js.es6
index 7db4ea2ce02..a711303f228 100644
--- a/app/assets/javascripts/discourse/models/post-stream.js.es6
+++ b/app/assets/javascripts/discourse/models/post-stream.js.es6
@@ -732,10 +732,15 @@ export default RestModel.extend({
     this._excerpts = this._excerpts || [];
     const stream = this.get('stream');
 
+    this._excerpts.loadNext = streamPosition;
+
     if (this._excerpts.loading) {
       return this._excerpts.loading.then(()=>{
         if(!this._excerpts[stream[streamPosition]]) {
-          return this.backfillExcerpts(streamPosition);
+
+          if (this._excerpts.loadNext === streamPosition) {
+            return this.backfillExcerpts(streamPosition);
+          }
         }
       });
     }