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Where is cache hit ratio in SQL Server?
Buffer Cache Hit Ratio can be viewed either through the SQL Server Performance Monitor under “SQLServer:Buffer Manager” (or when using a named instance “MSSQL$InstanceName:Buffer Manager”) or by searching the sys.
What is SQL Server buffer cache?
In SQL Server, the buffer cache is the memory that allows you to query frequently accessed data quickly. When data is written to or read from a SQL Server database, the buffer manager copies it into the buffer cache (aka the buffer pool).
What is the hit ratio of cache if a system?
What’s the Ideal Hit and Miss Ratios in Caches? Generally speaking, for most sites, a hit ratio of 95-99%, and a miss ratio of one to five percent is ideal.
What is a good hit rate?
However numerous professionals and empirical experience on different type of portfolios is hinting to fact that 50% is rather a good Hit Ratio. Very limited number of skilled investment professional are able to consistently maintain this level.
What should the buffer cache hit ratio be in SQL Server?
Ideally, SQL Server would read all pages from the buffer cache and there will be no need to read any from disk. In this case, the Buffer Cache Hit Ratio value would be 100. The recommended value for Buffer Cache Hit Ratio is over 90. When better performance is needed, the minimal acceptable value is 95. A lower value indicates a memory problem
What does it mean when the cache hit ratio is low?
Conversely, if the Buffer Cache Hit Ratiovalue is low, then this is a sure sign sign that SQL Server is under memory pressure and doing lots of physical disk reads to retrieve the required data. Buffer Cache hit ratio is in percentage and higher the better .
Is there a problem with the buffer cache?
There is no problem if the SQL Server shows a drop in the buffer cache hit ratio but the Page Life Expectancy hasn’t decreased very much. However, if both the buffer cache hit ratio and the Page Life Expectancy drop drastically, then a SQL Server performance problem is likely.
Why is it important to monitor SQL server buffer pool?
As the SQL Server buffer pool manages data cache, it’s important to monitor various buffer pool metrics as they help identify and solve memory pressure issues In this article, we will present 2 more Buffer Manager counters – Buffer Cache Hit Ratio and Page Life Expectancy.