From 1a8f61e60699c16d1356431987c88c1eb4fc8e84 Mon Sep 17 00:00:00 2001
From: Neil Kandalgaonkar <neilk@users.mediawiki.org>
Date: Tue, 20 Dec 2011 23:02:42 +0000
Subject: [PATCH] fix race condition in UploadFromChunks, followup to r104687

---
 includes/upload/UploadFromChunks.php | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/includes/upload/UploadFromChunks.php b/includes/upload/UploadFromChunks.php
index 01bc111ee6..3a5f8099be 100644
--- a/includes/upload/UploadFromChunks.php
+++ b/includes/upload/UploadFromChunks.php
@@ -187,8 +187,10 @@ class UploadFromChunks extends UploadFromFile {
 	 * Get the chunk db state and populate update relevant local values
 	 */
 	private function getChunkStatus(){
-		$dbr = $this->repo->getSlaveDb();
-		$row = $dbr->selectRow(
+		// get Master db to avoid race conditions. 
+		// Otherwise, if chunk upload time < replag there will be spurious errors
+		$dbw = $this->repo->getMasterDb();
+		$row = $dbw->selectRow(
 			'uploadstash', 
 			array( 
 				'us_chunk_inx',
-- 
2.20.1