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    <p>Short answer, <em>Yes</em> if you indexed the property.</p> <p>App Engine limits the number of property values a single entity can have on an index (number of rows * the number of columns) since it needs to create an index for each permutation. In the case of a single index property you have 5000rows * 1column = 5000.</p> <p>To show why App Engine does this let's take the example from their <a href="http://code.google.com/appengine/docs/python/datastore/queries.html#Big_Entities_and_Exploding_Indexes" rel="nofollow">documentation</a>.</p> <p>Model:</p> <pre><code>class MyModel(db.Model): x = db.StringListProperty() y = db.StringListProperty() </code></pre> <p>Index.yaml</p> <pre><code>indexes: - kind: MyModel properties: - name: x - name: y </code></pre> <p>Execution</p> <pre><code>e2 = MyModel() e2.x = ['red', 'blue'] e2.y = [1, 2] e2.put() </code></pre> <p>In this case, App Engine will have to create 12 indexes for this datastore entry alone, since effectively you can search for any combination of values:</p> <pre><code>x1 x2 y1 y2 x1 y1 x1 y2 x2 y1 x2 y2 y1 x1 y1 x2 y2 x1 y2 x2 </code></pre> <p>Now if you had 100 values in each property, you can imagine that the list would sky rocket to an obscene amount of queries.</p> <p>The equation is <em>something</em> like this:</p> <pre><code>len(x) + len(y) + (len(x)-1 * len(y) * (len(x) + len(y))) = number of indexed **2 values per property** 2 + 2 + (1 * 2 * (2 + 2)) = 12 **100 values per property** 100 + 100 + (99 * 100 * (100 + 100)) = 1,980,200 </code></pre>
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    1. POGoogle App Engine Datastore index cap
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    1. COSo here's my live example. I have a Calendar class and a child class, Event. Calendar has a list property of type List<Event>. My question is, can this list have more than 5000 indexed elements (events). I actually added over 5000 instances of event to that list and everything got stored with no errors, therefore I am confused. I may not understand the inner workings of the datastore, so any clarification is appreciated. Thanks.
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    2. COOne more thing, to clarify. Im am not using a custom index for that list, but GAE is automatically generating one because of the nature of the property.
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    3. COYou can have a list of more then 5000 items if you property is not 'indexed'. If your property is indexed, the maximum amount is 5000. To set a property not to be indexed you need to do following CalendarEvents = ListProperty(Event, indexed=False)
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