Objectify queries and strange eventual consistency

Question

I'm seeing some strange behavior related to objectify and eventual consistency. I have noticed this behavior while running some integration tests which make HTTP requests to an App Engine Java development server.

As I have wanted those tests to also work when being run against the real app engine environment, they are dealing with eventual consistency by repeating requests which return results based on eventually consistent queries.

I previously had accidentally the ObjectifyFilter in the wrong location in web.xml, so that the ObjectifyFilter would not run. Now that I moved it to the start of the filter chain, so that it actually runs, all my queries seem to always return consistent results! No more eventual consistency, that is!

For example one test does the following:

1. Request which adds a user with some username
2. Request which tries to authorize user with username and password. This will make a global query for users with given username, and the query should be eventually consistent, but it always finds the user entity.

I have no clue what is happening.

More info:

• I have checked that ofy().toString returns a different value for each request.
• I'm using -Ddatastore.default_high_rep_job_policy_unapplied_job_pct=50
• Appengine SDK version 1.8.6
• I'm making all writes inside transactions

Answer 1

Disable eventual consistency in your tests. Adding retries and sleeps does not change the logic of your code, it just complicates testing. There's no point in trying to test around eventually consistent behavior; just be aware that it exists.

I don't know the answer to your specific question because it's really about the specific behavior of the test harness. Re-read the unit testing guide closely; unapplied jobs are applied at odd points like the second time a query is run. It's only a very rough approximation of the eventually consistent behavior of the server environment.