CODEWITHSUNDEEP
google-app-enginegoogle-cloud-datastore
larsegar
larsegar

Reputation: 15

Google datastore performance: 2 gets vs 1 filter query

Using the GAE datastore, what option below would perform the best? (Assume that memcache is not available)

Option 1: DataModel: Entity User has some key, and an email address (the email can't be used as the key)

a) Perform a query on User that filters for a match by email

OR Option 2:

DataModel: Entity User has some key, Entity UserLogin has email address as key, and user key

a) Perform a get on UserLogin, then
b) Perform a get on User using the user key from UserLogin

Upvotes: 1

Views: 513

Answers (2)

Nick Johnson
Nick Johnson

Reputation: 101149

Get operations are substantially faster than queries, not to mention cheaper to execute. The sequence of two get operations is likely to be faster than a single query. For example, on the status dashboard, a get operation hovers at around 10 milliseconds, while a query operation hovers at around 80 milliseconds - but if this matters to you, I would encourage you to benchmark both and verify for yourself.

Upvotes: 4

Andrei Volgin
Andrei Volgin

Reputation: 41040

I believe that option 1 will be faster, because in option 2 you perform one operation, get the result, and only after that perform the second operation.

The difference, however, is negligible, unless you do it at least a few million times each day.

Upvotes: 1

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