Merge pull request #7995 from MicrosoftDocs/release-sqlseattle

Release sqlseattle

Author: MikeRayMSFT

docs/database-engine/configure-windows/hybrid-buffer-pool.md

@@ -0,0 +1,33 @@
+---
+title: "Hybrid Buffer Pool | Microsoft Docs"
+ms.custom: ""
+ms.date: "11/06/2018"
+ms.prod: sql
+ms.prod_service: high-availability
+ms.reviewer: ""
+ms.technology: configuration
+ms.topic: conceptual
+ms.assetid: 
+author: DBArgenis
+ms.author: Argenis.Fernandez
+manager: craigg
+---
+# Hybrid Buffer Pool
+[!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md](../../includes/appliesto-ss-xxxx-xxxx-xxx-md.md)]
+
+With SQL Server 2019 CTP 2.1 a new feature is introduced in the SQL Server database engine which allows it to directly access data pages in database files stored in persistent memory (PMEM) devices. 
+
+In a traditional system without persistent memory, SQL Server caches data pages in the buffer pool. With Hybrid Buffer Pool, SQL Server skips performing a copy of the page into the DRAM-based portion of the buffer pool, and instead references the page directly on the database file that lives on a PMEM device. Access to data files in PMEM for Hybrid Buffer Pool is performed using memory-mapped I/O, also known as enlightenment.
+
+Only clean pages can be referenced directly on a PMEM device. When a page becomes dirty it is kept in DRAM, and then eventually written back to the PMEM device.
+
+This feature is available on both Windows and Linux.
+
+## Enable Hybrid Buffer Pool
+
+On CTP 2.1, you must enable the startup trace flag 809 in order to use Hybrid Buffer Pool.
+
+## Best Practices for Hybrid Buffer Pool
+
+* When formatting your PMEM device on Windows use the largest allocation unit size available for NTFS (2MB in Windows Server 2019) and ensure the device has been enabled for DAX (DirectAccess)
+  

docs/sql-server/what-s-new-in-sql-server-ver15.md

@@ -35,6 +35,7 @@ Community technology preview (CTP) 2.1 is the latest public release of [!INCLUDE
   - UTF-8 collations support in [!INCLUDE[ssNoVersion](../includes/ssnoversion-md.md)] setup
   - Use derived table or view aliases in graph match queries
   - Improved diagnostic data for stats blocking
+  - Hybrid Buffer Pool
 - [Tools](#tools)
   - Azure Data Studio
 
@@ -285,9 +286,11 @@ Any [!INCLUDE[ssNoVersion](../includes/ssnoversion-md.md)] file that is placed o
 > [!NOTE]
 > For this preview release, enlightenment of files on persistent memory devices is only available on Linux. SQL Server on Windows supports persistent memory devices starting with SQL Server 2016.
 
-### Hybrid Buffer Pool (CTP 2.1)
+### Hybrid buffer pool (CTP 2.1)
 
-Hybrid Buffer Pool is a new feature of the SQL Server database engine where database pages sitting on database files placed on a persistent memory (PMEM) device will be directly accessed when required. Since PMEM devices provide very low latency for data access, the engine can forgo making a copy of the data in a "clean pages" area of the buffer pool and simply access the page directly on PMEM. Access is performed using memory mapped I/O, as is the case with enlightenment. This brings performance benefits from avoiding a copy of the page to DRAM, and from the avoidance of the I/O stack of the operating system to access the page on persistent storage. This feature is available on both SQL Server on Windows and SQL Server on Linux.   
+Hybrid buffer pool is a new feature of the SQL Server database engine where database pages sitting on database files placed on a persistent memory (PMEM) device will be directly accessed when required. Since PMEM devices provide very low latency for data access, the engine can forgo making a copy of the data in a "clean pages" area of the buffer pool and simply access the page directly on PMEM. Access is performed using memory mapped I/O, as is the case with enlightenment. This brings performance benefits from avoiding a copy of the page to DRAM, and from the avoidance of the I/O stack of the operating system to access the page on persistent storage. This feature is available on both SQL Server on Windows and SQL Server on Linux.
+
+For more information, see [Hybrid buffer pool](../database-engine/configure-windows/hybrid-buffer-pool.md)
 
 ### Support for columnstore statistics in DBCC CLONEDATABASE (CTP 2.0)