From 7a60a5e4999e19115a2d8e144e8afe48ceb8b808 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Sat, 25 Feb 2017 10:39:13 +0900
Subject: [PATCH] Lock the BeatmapDatabase's connection during imports.

This should avoid any potential issues with intertwined transactions on the same connection while still allowing higher throughput when importing.
---
 osu.Game/Database/BeatmapDatabase.cs | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/osu.Game/Database/BeatmapDatabase.cs b/osu.Game/Database/BeatmapDatabase.cs
index 66c348279d..ff58031c57 100644
--- a/osu.Game/Database/BeatmapDatabase.cs
+++ b/osu.Game/Database/BeatmapDatabase.cs
@@ -181,15 +181,18 @@ namespace osu.Game.Database
 
         public void Import(IEnumerable<BeatmapSetInfo> beatmapSets)
         {
-            connection.BeginTransaction();
-
-            foreach (var s in beatmapSets)
+            lock (connection)
             {
-                connection.InsertWithChildren(s, true);
-                BeatmapSetAdded?.Invoke(s);
-            }
+                connection.BeginTransaction();
 
-            connection.Commit();
+                foreach (var s in beatmapSets)
+                {
+                    connection.InsertWithChildren(s, true);
+                    BeatmapSetAdded?.Invoke(s);
+                }
+
+                connection.Commit();
+            }
         }
 
         public void Delete(BeatmapSetInfo beatmapSet)