SQL Server buffer pool

An SQL server buffer pool is nothing but a place in system memory that is use for caching tables and index data page for read or modify from the disk. It is also known as sql server buffer cache. The primary purpose of the SQL buffer pool is to reduce database file I/O and improve the response time for data retrieval.

 Hard disks are slow, memory is fast. Whenever data is written to or read from a SQL Server database, it will be copied into memory by the buffer manager. The buffer pool will use as much memory as is allocated to it in order to hold as many pages of data as possible. When the buffer cache fills up, older and less used data will be purged in order to make room for newer data.

Below sql script is use to find the buffer pages

SELECT                 COUNT(*) AS buffer_cache_pages,                 COUNT(*) * 8 / 1024 AS buffer_cache_used_MB FROM sys.dm_os_buffer_descriptors;