In this article I'm going to talk about one of the new feature of SQL Server 2014. As you know SQL Server 2014 contains some interesting new features. Although SQL Server Standard Edition is limited to 128GB of memory, teams deploying on Standard Edition have an option to fit more of their working set in low latency storage Buffer Pool Extensions that are introduced with SQL Server 2014. Well, the Buffer Pool is one of the main memory consumers in SQL Server. When you read data from your storage, the data is cached in the Buffer Pool. SQL Server caches Execution Plans in the Plan Cache, which is also part of the Buffer Pool. The more physical memory you have, the larger your Buffer Pool will be (configured through the Max Server Memory setting).

sql server 2014 with asphostportal.com

Creating a buffer pool extension for SQL Server 2014 is like being able to define a different page file in Windows. As data pages move into memory, they begin to fill up the buffer pool. If the buffer pool fills up, the less frequently used pages will be paged to disk. Then when they're needed again, they'll be swapped with something else in the buffer pool and moved back into memory. The buffer pool extension option allows you to define an SSD as a buffer file location. Because SSD is so much faster than spinning disk, the paging is considerably quicker, which increases performance dramatically in some cases. You can define a buffer pool extension file up to 32 times the size of your memory.

Prior to SQL Server 2014, the management of data and index pages in the buffer pool was handled by the buffer manager. This has not changed with the release of SQL Server 2014, a change in the architecture has allowed for creation of a hybrid buffer pool. The hybrid buffer pool now consists of the existing buffer pool plus an extension that resides on nonvolatile storage or an SSD. The buffer manager still deals with identifying those pages in the buffer pool that can be expunged, when required pages for a request are not residing in memory but on disk. This practice is still handled and undertaken by the buffer manager. In addition to the buffer manager deciding on which pages should be in the buffer pool or not, it is now identifying those pages which are considered as “clean pages” and migrating those pages out of the buffer pool onto the BPE to allow for even more data to reside in the buffer pool. This practice is providing the following benefits to your SQL Server environment (as stated in the Microsoft BPE article):

  • Increased random I/O throughput
  • Reduced I/O latency
  • Increased transactional throughput
  • Improved read performance with a larger hybrid buffer pool
  • A caching architecture that can take advantage of present and future low-cost memory drives