From f8a6721703bad8881a993e490a8987891290ec5e Mon Sep 17 00:00:00 2001
From: Albert Santoni <albert.santoni@sourcefabric.org>
Date: Mon, 19 Oct 2015 17:31:26 -0400
Subject: [PATCH] Increase transaction isolation level for track scheduling and
 moving

---
 airtime_mvc/application/models/Scheduler.php | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/airtime_mvc/application/models/Scheduler.php b/airtime_mvc/application/models/Scheduler.php
index 51b964589..e5ecd707c 100644
--- a/airtime_mvc/application/models/Scheduler.php
+++ b/airtime_mvc/application/models/Scheduler.php
@@ -955,6 +955,10 @@ class Application_Model_Scheduler
         $this->con->beginTransaction();
 
         try {
+            //Increase the transaction isolation level to prevent two concurrent requests from potentially resulting
+            //in tracks scheduled at the same time.
+            $this->con->exec("SET TRANSACTION ISOLATION LEVEL SERIALIZABLE");
+
             $this->validateMediaItems($mediaItems); //Check for missing files, etc.
             $this->validateRequest($scheduleItems, true);
 
@@ -1005,6 +1009,9 @@ class Application_Model_Scheduler
         //$this->con->useDebug(true);
 
         try {
+            //Increase the transaction isolation level to prevent two concurrent requests from potentially resulting
+            //in tracks scheduled at the same time.
+            $this->con->exec("SET TRANSACTION ISOLATION LEVEL SERIALIZABLE");
 
             $this->validateItemMove($selectedItems, $afterItems[0]);
             $this->validateRequest($selectedItems);