Indexed Views In SQL Server: No Filtered Indexes Or Filtered Statistics

Half Baked


In my quest to love indexed views more, I’m always trying new things with them to solve problems.

Occasionally, I am pleasantly surprised by what can be accomplished with them. Occasionally.

Today was not an occasion. Let’s take an unfortunate look.

CREATE TABLE
    dbo.IndexedViewMe
(
    id int PRIMARY KEY CLUSTERED
);
GO 

CREATE VIEW 
    dbo.TheIndexedView
WITH SCHEMABINDING
AS
SELECT
    ivm.id
FROM dbo.IndexedViewMe AS ivm;
GO 

CREATE UNIQUE CLUSTERED INDEX
    uqi
ON dbo.TheIndexedView
    (id);

INSERT 
    dbo.IndexedViewMe
(
    id
)
SELECT
    x.c
FROM 
(
    SELECT 1 
      UNION ALL 
    SELECT 2
) AS x(c);

This gives us a tiny little table and indexed view. If we try to do either of these things, it doesn’t go well:

CREATE INDEX 
    i
ON dbo.TheIndexedView
    (id)
WHERE 
    id = 2;

Msg 10610, Level 16, State 1, Line 40

Filtered index ‘i’ cannot be created on object ‘dbo.TheIndexedView’ because it is not a user table. Filtered indexes are only supported on tables.

If you are trying to create a filtered index on a view, consider creating an indexed view with the filter expression incorporated in the view definition.

CREATE STATISTICS 
    s
ON dbo.TheIndexedView
    (id)
WHERE 
    id = 2;

Msg 10623, Level 16, State 1, Line 47

Filtered statistics ‘s’ cannot be created on object ‘dbo.TheIndexedView’ because it is not a user table. Filtered statistics are only supported on user tables.

Sort of a bummer, that. And it strikes me that it’s an odd limitation — especially for the statistics — but what can you do?

Indexed views haven’t changed aside from bug fixes in forever and a day. I doubt there’ll be any real investment in enhancing them anytime soon.

Thanks for reading!

Going Further


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