![]() They help by giving SQL Server insight into how much data will be accessed. Statistics help SQL Server with the gathering / processing of the data. ![]() So, how does SQL Server “get” to the data? Processing Data However, the main point is that you’re requesting a data set – not HOW that data set should be found/processed. ![]() When you submit a request to SQL Server to access data, you usually write a Transact-SQL statement – in the form of an actual SELECT or possibly execute a stored procedure (and, yes, there are other options). To understand this, I want to talk a bit about accessing data and the process of optimization. And, SQL Server often needs some with certain data patterns and data sets – to really optimize effectively. However, it’s important to know that while some aspects of statistics ARE handled automatically they’re not perfect. If you want to read a bit more about this – check out Erin’s SQL101 post: SQLskills SQL101: Updating SQL Server Statistics Part I – Automatic Updates and why it’s generally better to update statistics manually (but through a more selective/automated process) here: SQLskills SQL101: Updating SQL Server Statistics Part II – Scheduled Updates However, there are some products/guidance out there that recommends that you turn this off.
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