google-cloud-datastore

I have been playing around with google app engine and its datastore recently and created a datamodel and relationships using reference properties. However I am unclear about the concept of ancestors wrt the datastore. What is their purpose and why should I use them? How do they relate to reference properties of datastore entities? Another benefit of entity groups/ancestors is to create islands of strong consistency (as opposed to eventual consistency). For instance, you could have a project and its tasks. Without ancestors, you could 'close' a task, go back to the tasks list screen for the

I'm currently building an app for deployment to GAE, using Objectify 3.1. I am getting strange results when attempting to do a query with an order() clause. My domain: public class InvoiceLineItem { private int units; private BigDecimal unitCost; private BigDecimal extendedCost; private String description; @Parent Key<Invoice> invoice; } I am attempting to gather all of the InvoiceLineItems associated with a given Invoice using the following: ofy ().query (InvoiceLineItem.class).ancestor (invoiceKey).list ( ); In my test case, this works just fine, returning 2 rows as expected. However, when I

Coming from a relational database background, as I'm sure many others are, I'm looking for some solid guidelines for setting up / designing my datastore on Google App Engine. Are there any good rules of thumb people have for setting up these kinds of schema-less data stores? I understand some of the basics such as denormalizing since you can't do joins, but I was wondering what other recommendations people had. The particular simple example I am working with concerns storing searches and their results. For example I have the following two models defined in my Google App Engine app using Python

I'm working on providing an API via GAE that will allow users to page forwards and backwards through a set of entities. I've reviewed the section about cursors on the NDB Queries documentation page , which includes some sample code that describes how to page backwards through query results, but it doesn't seem to be working as desired. I'm using GAE Development SDK 1.8.8. Here's a modified version of that example that creates 5 sample entities, gets and prints the first page, steps forward into and prints the second page, and attempts to step backwards and print the first page again: import

Can we start a dynamic backend programatically? mean while when a backend is starting how can i handle the request by falling back on the application(i mean app.appspot.com). When i stop a backend manually in admin console, and send a request to it, its not starting "dynamically" Dynamic backends come into existence when they receive a request, and are turned down when idle; they are ideal for work that is intermittent or driven by user activity. Resident backends run continuously, allowing you to rely on the state of their memory over time and perform complex initialization. http://code

I am trying to perform some data processing in a GAE application over data that is stored in the Datastore. The bottleneck point is the throughput in which the query returns entities and I wonder how to improve the query's performance. What I do in general: everything works in a task queue, so we have plenty of time (10 minute deadline). I run a query over the ndb entities in order to select which entities need to be processed. as the query returns results, I group entities in batches of, say, 1000 and send them to another task queue for further processing. the stored data is going to be large