AppEngine：运行时限制

I'm an avid GAE/J user, now trying to create my first GAE/go project.

What are the limitations of the AppEngine Go runtime compared to Java or Python runtimes? Missing APIs? Runtime limitations?

https://developers.google.com/appengine/features/ covers what features are implemented by which runtimes.

What I was able to find out so far is:

1. DB Query: missing composite filters (AND and OR).
2. DB Query: missing "member of" filter operator (IN).
3. No App Identity API Edit: this seems to exist, but is not listed under services
4. No Prospective Search