From 997bfe51df63715beae88f9d0a22086e6735ab75 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 8 May 2026 03:54:25 +0000
Subject: [PATCH 1/2] Initial plan


From 3c00675d5a539af072eab1bc35dd20c24aee873f Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 8 May 2026 03:57:50 +0000
Subject: [PATCH 2/2] Remove forced PK_NewTasks index hint from _LockNextTask
 and add covering index

Agent-Logs-Url: https://github.com/microsoft/durabletask-mssql/sessions/8ca0a940-d65f-45e4-96c8-2f6de7571ad6

Co-authored-by: berndverst <4535280+berndverst@users.noreply.github.com>
---
 src/DurableTask.SqlServer/Scripts/logic.sql     |  3 +--
 .../Scripts/schema-1.7.0.sql                    | 17 +++++++++++++++++
 src/common.props                                |  2 +-
 3 files changed, 19 insertions(+), 3 deletions(-)
 create mode 100644 src/DurableTask.SqlServer/Scripts/schema-1.7.0.sql

diff --git a/src/DurableTask.SqlServer/Scripts/logic.sql b/src/DurableTask.SqlServer/Scripts/logic.sql
index 6fbc422..835e65d 100644
--- a/src/DurableTask.SqlServer/Scripts/logic.sql
+++ b/src/DurableTask.SqlServer/Scripts/logic.sql
@@ -1282,7 +1282,6 @@ BEGIN
     -- Table order for this sproc: NewTasks --> Payloads
 
     -- Update (lock) and return a single row.
-    -- The PK_NewTasks hint is specified to help ensure in-order selection.
     -- TODO: Filter out tasks for instances that are in a non-running state (suspended, etc.)
     UPDATE TOP (1) NewTasks WITH (READPAST)
     SET
@@ -1291,7 +1290,7 @@ BEGIN
 	    [LockExpiration] = @LockExpiration,
         [DequeueCount] = [DequeueCount] + 1
     FROM
-        NewTasks WITH (INDEX (PK_NewTasks))
+        NewTasks
     WHERE
         [TaskHub] = @TaskHub AND
 	    ([LockExpiration] IS NULL OR [LockExpiration] < @now) AND
diff --git a/src/DurableTask.SqlServer/Scripts/schema-1.7.0.sql b/src/DurableTask.SqlServer/Scripts/schema-1.7.0.sql
new file mode 100644
index 0000000..09ad453
--- /dev/null
+++ b/src/DurableTask.SqlServer/Scripts/schema-1.7.0.sql
@@ -0,0 +1,17 @@
+-- Copyright (c) Microsoft Corporation.
+-- Licensed under the MIT License.
+
+-- PERSISTENT SCHEMA OBJECTS (tables, indexes, types, etc.)
+--
+-- The contents of this file must never be changed after
+-- being published. Any schema changes must be done in
+-- new schema-{major}.{minor}.{patch}.sql scripts.
+
+-- Add a covering index on NewTasks to improve the performance of _LockNextTask.
+-- This allows SQL Server to efficiently find unlocked, visible tasks without
+-- performing a full clustered-index scan, which is important under high concurrency
+-- when there may be a backlog of locked or not-yet-visible tasks.
+IF NOT EXISTS (SELECT 1 FROM sys.indexes WHERE object_id = OBJECT_ID('__SchemaNamePlaceholder__.NewTasks') AND name = 'IX_NewTasks_LockNext')
+    CREATE NONCLUSTERED INDEX IX_NewTasks_LockNext ON __SchemaNamePlaceholder__.NewTasks(TaskHub, LockExpiration, VisibleTime)
+        INCLUDE (SequenceNumber, LockedBy, DequeueCount)
+GO
diff --git a/src/common.props b/src/common.props
index 7f63f5c..29f4887 100644
--- a/src/common.props
+++ b/src/common.props
@@ -16,7 +16,7 @@
   <!-- Version settings: https://andrewlock.net/version-vs-versionsuffix-vs-packageversion-what-do-they-all-mean/ -->
   <PropertyGroup>
     <MajorVersion>1</MajorVersion>
-    <MinorVersion>6</MinorVersion>
+    <MinorVersion>7</MinorVersion>
     <PatchVersion>0</PatchVersion>
     <VersionPrefix>$(MajorVersion).$(MinorVersion).$(PatchVersion)</VersionPrefix>
     <VersionSuffix></VersionSuffix>