who use index of SimpleDB?

SimpleDB declare that any column of each item will be indexed automatically. I think indexing will occupy much storage and slow performance, and is there many applications which use index of SimpleDB frequently ? or Is there some classic application cannot run without SimpleDB index ?开发者_JAVA百科

thank you very much.

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I think you're approaching SimpleDB a bit too much like one would a normal SQL-database. The always-indexed nature of SimpleDB is built into the core of the product and you don't have to worry about the index storage size since all you're billed for is the storage of the actual attribute keys and values (aside from queries)

One of the big advantages of using SimpleDB is that you outsource the performance tuning to others and can concentrate on your application logic.

Since the only real cost of keeping indices (used or unused) is disk space there should be no performance problems. Insertions maybe but I believe the eventually consistent nature of SimpleDB alleviates any such overhead.

I'm not sure as to the exact meaning of the second part of your question. There's indeed plenty of applications which use SimpleDB as their backing storage. Whether or not it's appropriate for you is something that only you can answer but index performance should not be a problem.

In the Amazon case studies for SimpleDB you'll find a bunch of companies which use SimpleDB as their only backing store or as a complement.