From a9cc12c6673f3cddaf06e10d378afbe35c5c7dbe Mon Sep 17 00:00:00 2001
From: barisusakli <barisusakli@gmail.com>
Date: Thu, 24 Mar 2016 21:01:20 +0200
Subject: [PATCH] retry failed upserts closes #4467

---
 src/database/mongo/sorted.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/database/mongo/sorted.js b/src/database/mongo/sorted.js
index 0baa08b2f6..d8a9205ce0 100644
--- a/src/database/mongo/sorted.js
+++ b/src/database/mongo/sorted.js
@@ -524,6 +524,13 @@ module.exports = function(db, module) {
 		data.score = parseInt(increment, 10);
 
 		db.collection('objects').findAndModify({_key: key, value: value}, {}, {$inc: data}, {new: true, upsert: true}, function(err, result) {
+			// if there is duplicate key error retry the upsert
+			// https://github.com/NodeBB/NodeBB/issues/4467
+			// https://jira.mongodb.org/browse/SERVER-14322
+			// https://docs.mongodb.org/manual/reference/command/findAndModify/#upsert-and-unique-index
+			if (err && err.message.startsWith('E11000 duplicate key error')) {
+				return module.sortedSetIncrBy(key, increment, value, callback);
+			}
 			callback(err, result && result.value ? result.value.score : null);
 		});
 	};