Limit on Google App Engine Entities' Collection attributes

Okay, so as many 开发者_如何转开发of you may know, one can define entities with attributes like

List<String> lotsOStrings;

or in general

    Collection<T> stuff;

My question is, if I dont index that attribute, is there a limit to how big it's size() can be?

Yes the limit is 5000 entries and if you want to go upper than 5000, you shouldn't use a list but you should denormalize your model with an external entity representing the relation.

Apparently, even if you remove the index, the limitation of 5000 is still present.

Using an index on a such list can be quite dangerous because for each entry in the list, it will create lots of entries in indexes.
Read this to have more info: http://code.google.com/intl/fr/appengine/docs/python/datastore/queries.html#Big_Entities_and_Exploding_Indexes

I think list properties are constrained to 5000 entries. I don't if taking them off the index makes a difference, though.