Google App Engine datastore supports only 200 indexes

I am a newbi开发者_StackOverflow中文版e to app engine datastore. I am currently evaluating to migrate my existing webapp to app engine. I found that the hard limit for indexes is 200 for an application. So, i am really confused whether this constraint forces many limitations on the app engine datastore design.[ for eg. no of entity kinds, no of properties in an entity] etc.

Please advice me on this

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The answer you already got in Google Groups, copied below, is a pretty good one.

The number if indexes isn't affected by the number of properties on an entity. It only has to do with the number of indexes for "complex queries" that are needed in your application (i.e. Those in index.yaml). So the number of indexes created automatically (by properties on indexes) are probably only limited by your available storage and doesn't limit the number of entities or properties on entities.

See:
http://code.google.com/appengine/docs/python/config/indexconfig.html
http://code.google.com/appengine/docs/python/datastore/propertyclass....

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For dynamic queries, one way to get around the limit of 200 indices is detailed at https://developers.google.com/appengine/articles/indexselection

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The composite index quota might become an issue if your application grows large, as in number of features, not users. Here are some open tickets:

https://code.google.com/p/googleappengine/issues/detail?id=8305 https://code.google.com/p/googleappengine/issues/detail?id=287#c6

Note the comments regarding buying premium support to get around this issue.

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I'm unsure where you got the 200 number but that is not accurate. To my knowledge there is no limit to the number of indexes per application, but there is a limitation to the number of indexes per model. I believe there is a limitation of 5000 indexed properties on a model.

For more information on indexes you should get familiar with the Queries and Indexes section of the AppEngine documentation.