From a892ae1567284e800e89fd87d88e49943ef85386 Mon Sep 17 00:00:00 2001
From: Stephan <stephane@umbraco.dk>
Date: Mon, 11 Feb 2019 11:35:21 +0100
Subject: [PATCH] Add missing index on UserLogin table (prevents deadlocks)

---
 src/Umbraco.Core/Migrations/MigrationBase_Extra.cs | 6 ++++++
 src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs | 2 +-
 src/Umbraco.Core/Persistence/Dtos/UserLoginDto.cs  | 7 +++++--
 src/Umbraco.Core/Umbraco.Core.csproj               | 1 +
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/Umbraco.Core/Migrations/MigrationBase_Extra.cs b/src/Umbraco.Core/Migrations/MigrationBase_Extra.cs
index 6d936e8407..bf07e4d08f 100644
--- a/src/Umbraco.Core/Migrations/MigrationBase_Extra.cs
+++ b/src/Umbraco.Core/Migrations/MigrationBase_Extra.cs
@@ -96,6 +96,12 @@ namespace Umbraco.Core.Migrations
             return tables.Any(x => x.InvariantEquals(tableName));
         }
 
+        protected bool IndexExists(string indexName)
+        {
+            var indexes = SqlSyntax.GetDefinedIndexes(Context.Database);
+            return indexes.Any(x => x.Item2.InvariantEquals(indexName));
+        }
+
         protected bool ColumnExists(string tableName, string columnName)
         {
             var columns = SqlSyntax.GetColumnsInSchema(Context.Database).Distinct().ToArray();
diff --git a/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs b/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs
index a9444a0918..cfa82748d2 100644
--- a/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs
+++ b/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs
@@ -127,7 +127,7 @@ namespace Umbraco.Core.Migrations.Upgrade
             To<ConvertRelatedLinksToMultiUrlPicker>("{ED28B66A-E248-4D94-8CDB-9BDF574023F0}");
             To<UpdatePickerIntegerValuesToUdi>("{38C809D5-6C34-426B-9BEA-EFD39162595C}");
             To<RenameUmbracoDomainsTable>("{6017F044-8E70-4E10-B2A3-336949692ADD}");
-
+            To<AddUserLoginDtoDateIndex>("98339BEF-E4B2-48A8-B9D1-D173DC842BBE");
 
             //FINAL
 
diff --git a/src/Umbraco.Core/Persistence/Dtos/UserLoginDto.cs b/src/Umbraco.Core/Persistence/Dtos/UserLoginDto.cs
index e03efa8fe9..d7d02631b7 100644
--- a/src/Umbraco.Core/Persistence/Dtos/UserLoginDto.cs
+++ b/src/Umbraco.Core/Persistence/Dtos/UserLoginDto.cs
@@ -30,11 +30,14 @@ namespace Umbraco.Core.Persistence.Dtos
         /// Updated every time a user's session is validated
         /// </summary>
         /// <remarks>
-        /// This allows us to guess if a session is timed out if a user doesn't actively log out
-        /// and also allows us to trim the data in the table
+        /// <para>This allows us to guess if a session is timed out if a user doesn't actively
+        /// log out and also allows us to trim the data in the table.</para>
+        /// <para>The index is IMPORTANT as it prevents deadlocks during deletion of
+        /// old sessions (DELETE ... WHERE lastValidatedUtc &lt; date).</para>
         /// </remarks>
         [Column("lastValidatedUtc")]
         [NullSetting(NullSetting = NullSettings.NotNull)]
+        [Index(IndexTypes.NonClustered, Name = "IX_userLoginDto_lastValidatedUtc")]
         public DateTime LastValidatedUtc { get; set; }
 
         /// <summary>
diff --git a/src/Umbraco.Core/Umbraco.Core.csproj b/src/Umbraco.Core/Umbraco.Core.csproj
index b80d607d4f..f5bdc417bd 100755
--- a/src/Umbraco.Core/Umbraco.Core.csproj
+++ b/src/Umbraco.Core/Umbraco.Core.csproj
@@ -367,6 +367,7 @@
     <Compile Include="Migrations\Upgrade\V_7_9_0\AddUmbracoAuditTable.cs" />
     <Compile Include="Migrations\Upgrade\V_7_9_0\AddUmbracoConsentTable.cs" />
     <Compile Include="Migrations\Upgrade\V_7_9_0\CreateSensitiveDataUserGroup.cs" />
+    <Compile Include="Migrations\Upgrade\V_8_0_0\AddUserLoginDtoDateIndex.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\ConvertRelatedLinksToMultiUrlPicker.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\AddContentTypeIsElementColumn.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\AddLogTableColumns.cs" />