App Engine: How to "reset" the datastore?

Question

Well, I'm developing in App Engine (Java) and after a lot of tries and deployments, I need to reset the datastore. There is a lot of random data I added to test performance, and besides that the entities changed a lot, so I need to delete all: data, tables, indexes.

How can I do that?

Solution 1

There is no built in command equivalent to DROP TABLE or TRUNCATE TABLE in SQL. You just need to create a "delete everything" page in your app, then repeatedly call that page via a script. In that page, you want to delete as many entities as you can yet still reasonably expect to finish before the request times out. The exact code depends on whether you're using JDO/JPA or the low level API. (the low level API will be faster because you can use batch operations.)

This previous SO question is pretty much the same, only for Python

Solution 2

Sorry to wake this thread up, but just in case I'd like to add a tip for noobs like me (finally found the answer in google documentation) :

If you want to reset the Local datastore (for example while developping using eclipse) all at once, shut down the server, find the file 'local_db.bin' in your project (should be in the WEB-INF/appengine-generated/ directory), and delete it.

Works fine with java, didn't try with python yet.

++

Solution 3

Clearing the Development Server Datastore

The development web server uses a local version of the datastore for testing your application, using temporary files. The data persists as long as the temporary files exist, and the web server does not reset these files unless you ask it to do so.

If you want the development server to erase its datastore prior to starting up, use the --clear_datastore option when starting the server:

dev_appserver.py --clear_datastore helloworld/

Using the Datastore

Solution 4

Just execute a query without a filter to fetch all the entities, and delete them one by one.

import javax.servlet.http.*;

import com.google.appengine.api.datastore.DatastoreService;
import com.google.appengine.api.datastore.DatastoreServiceFactory;
import com.google.appengine.api.datastore.Entity;
import com.google.appengine.api.datastore.PreparedQuery;
import com.google.appengine.api.datastore.Query;

public class MyServlet extends HttpServlet {
        public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws IOException {

        DatastoreService datastore = 
                    DatastoreServiceFactory.getDatastoreService();

    Query mydeleteq = new Query();
    PreparedQuery pq = datastore.prepare(mydeleteq);
    for (Entity result : pq.asIterable()) {
        datastore.delete(result.getKey());      
    }   
}

Solution 5

sorry to be so late on this, but I was just trying to do the same myself...

I logged into my account (appengine.google.com) and found the option to browse the datastore through an admin utility (datastore/dataviewer)... that allows create/update/delete.

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