Updating a view mssql
I’ve been asked a lot of questions about updating statistics in SQL Server over the years. Here’s a rundown of all the practical questions that I tend to get about how to maintain these in SQL Server.I don’t dig into the internals of statistics and optimization in this post. ⇒ Be a proactive: If you have millions of rows in some of your tables, you can get burned by doing no statistics maintenance at all if query performance stats to get slow and out of date statistics are found to be the cause.These are not considered ‘user created’ even though our user query was the cause of them being auto-generated.(“User created” means someone ran a CREATE STATISTICS command.) SQL Server can now use the statistic on Gender and the statistic on First Name Id for future queries that run. First Name By Year table has a clustered primary key, and here is the statistic that was created along with that index: If columns are important enough to index, SQL Server assumes that it’s also important to estimate how many rows would be returned by that index when you query it.The SQL Server query optimizer uses statistics to estimate how many rows will be returned by parts of your query. By default, the SQL Server optimizer will see that no statistics exists, and wait while two column statistics are created on the First Name Id and Gender columns.Statistics are small, and are created super fast– my query isn’t measurably any faster when I run it a second time.
Mukesh is a passionate web developer who has keen interest in open source technologies, programming & blogging.With default database settings, the SQL Server optimizer looks at how many changes have occurred for a given column statistic as part of query optimization.If it looks like a significant amount of rows in the column have changed, SQL Server updates the statistic, then optimizes the query.A view is stored as a SELECT statement in the database.DML operations on a view like INSERT, UPDATE, DELETE affects the data in the original table upon which the view is based.