When do indexed views get updated

In addition, SQL Server requires all object references in an indexed view to include the two-part naming convention i. When the data of the underlying tables changes, the data in the indexed view is also automatically updated. This causes a write overhead for the referenced tables. It means that when you write to the underlying table, SQL Server also has to write to the index of the view. Therefore, you should only create an indexed view against the tables that have in-frequent data updates.

Note that indexed views weren't available until SQL Server I doubt you're using ! You're link goes to newer documentation - be aware that in such documentation, MS sometimes say "supported since When I look at the link I posted, I see no reference to when support started, so maybe it was a bug in the documentation at the time I looked at it.

Add a comment. Active Oldest Votes. T ID int not null go create view dbo. V with schemabinding as select ID from dbo. T go create unique clustered index I on dbo. Even back in the version of the documentation , this restriction is mentioned: After the clustered index is created, any connection attempting to modify the base data for the view must also have the same option settings required to create the index.

Improve this answer. Sign up or log in Sign up using Google. The update is not big concern as far as the speed is acceptable. The actual indexed view is far more complicate than I described here. It includes some compute columns and it also needs to join with other large tables. The indexed view does make the select query fast! I also found when I limit the indexed view number to less than and I will get acceptable update performance. But I cannot find any article to support this assumption.

Anyway, I will make the design change to limit the indexed view number to less than You said performance was good up to views, but were those views the real McCoy, or just the dummy you showed us? The cost for maintaining a view certainly depends on the complexity. As for the change in performance at views, it may be that they change some internal algorithm in this case. I doubt that you would ever find any documentation on this number.

My experience is that they keep such implementation details undocumented on purpose. There is also the possibility that the actual limit depends on available RAM etc.

Indexed views can be useful, but of them on a single table? Creating a unique clustered index on a view improves query performance because the view is stored in the database in the same way a table with a clustered index is stored. The query optimizer may use indexed views to speed up the query execution. The view does not have to be referenced in the query for the optimizer to consider that view for a substitution.

The following steps are required to create an indexed view and are critical to the successful implementation of the indexed view:. When executing DML 1 on a table referenced by a large number of indexed views, or fewer but very complex indexed views, those referenced indexed views will have to be updated as well. As a result, DML query performance can degrade significantly, or in some cases, a query plan cannot even be produced.

Evaluating the same expression can produce different results in the Database Engine when different SET options are active when the query is executed. To make sure that the views can be maintained correctly and return consistent results, indexed views require fixed values for several SET options.

The SET options in the following table must be set to the values shown in the Required Value column whenever the following conditions occur:. The definition of an indexed view must be deterministic. Deterministic expressions always return the same result any time they are evaluated with a specific set of input values.

Only deterministic functions can participate in deterministic expressions. For example, the DATEADD function is deterministic because it always returns the same result for any given set of argument values for its three parameters.

GETDATE is not deterministic because it is always invoked with the same argument, but the value it returns changes each time it is executed. This means the column is not deterministic or not precise.