Quota on number of entity types / kinds?

[RyanD]

A couple of quota questions:

1) Mainly: I'm looking to develop an application that has an
*unbounded* number of entity types / kinds (by using the low level
Java API). Is this possible, or is there some limit to the number of
entity types / kinds that an application may have?

2) Any limit on the number of entries for a single entity type /
kind?

Thanks,

Ryan

[Ikai L (Google)]

Ryan,

The answer to both of your questions is "no" with a gotcha. Unlike an RDBMS in which tables can enforce some degree of the concept of "Type", BigTable has no concept of type or tables. Entities are mapped by an Entity index, which in turn is also stored in BigTable. Searchable/filterable fields on an entity also generate indexes, and composite indexes are also generated depending on what queries are being done. There is no limit to the amount of entities you can store, but you will only be able to retrieve 1000 with any given query until we release cursor support in an upcoming release.

We'll be publishing an article that describes how the data store works underneath the hood soon. I'll post it when it goes live.

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Ikai Lan
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[RyanD]

One followup question to the case described above:

If I want entity types that are application controlled, and
dynamically created through the low level API (as described above),
then there is no way to create indexes unless there is also some kind
of low level API for index creation. As it stands the index files
appear to be a static part of the uploaded application files, which
wouldn't work with dynamically create entity types. Am I
understanding this index "limitation" correctly? If so, are there any
long term plans for a low level index API?

Ryan

> > google-appengi...@googlegroups.com<google-appengine%2Bunsubscrib e...@googlegroups.com>

[RyanD]

Hmm, nevermind, I see the issue in the issue tracker related to an
"Index Management API". I guess I'm not the only one. Starring it.

[Nickolas Daskalou]

You could get the dev server to update index.yaml with the dynamic indexes by running a query on the dev Datastore that would require the desired index on your dynamic entity kind. However if it's not possible to know all the dynamic entity kinds you'll need on the live server, then this wouldn't work.

What about creating a base PolyModel class, and have all your dynamic entity kinds inherit from that?

2010/1/9 RyanD <ry...@dewell.org>

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