Why can't I simply add an index that includes

Question

I have a table in SQL Server database which I want to be able to search and retrieve data from as fast as possible. I don't care about how long time it takes to insert into the table, I am only interested in the speed at which I can get data.

The problem is the table is accessed with 20 or more different types of queries. This makes it a tedious task to add an index specially designed for each query. I'm considering instead simply adding an index that includes ALL columns of the table. It's not something you would normally do in "good" database design, so I'm assuming there is some good reason why I shouldn't do it.

Can anyone tell me why I shouldn't do this?

UPDATE: I forgot to mention, I also don't care about the size of my database. It's OK that it means my database size will grow larger than it needed to

Answer 1

You are having a fundamental misunderstanding how indexes work.

Read this explanation "how multi-column indexes work".

The next question you might have is why not creating one index per column--but that's also a dead-end if you try to reach top select performance.

You might feel that it is a tedious task, but I would say it's a required task to index carefully. Sloppy indexing strikes back, as in this example.

Note: I am strongly convinced that proper indexing pays off and I know that many people are having the very same questions you have. That's why I'm writing a the a free book about it. The links above refer the pages that might help you to answer your question. However, you might also want to read it from the beginning.