Here are the descriptions and calculation models for each of these metrics. The URL
Fetch service is covered in Chapter 8 in more detail.
URL Fetch API Calls : The total number of times the application
accesses the URL Fetch service to perform an HTTP or HTTPS
URL Fetch Data Sent : Each request to the URL Fetch service gets
measured for data sent as part of the request. This also counts toward
your Outgoing Bandwidth quota.
URL Fetch Data Received : The amount of data received in response
to a URL Fetch request. This also counts toward your Outgoing
XMPP is new as of version 1.2.5 of the Java SDK for App Engine. This service allows
your App Engine application to interact with XMPP services like Google Talk. We'll
show an example of that type of application in Chapter 9. Table 2-7 shows the limits
for the XMPP services.
Table 2-7. App Engine Quotas for the XMPP Service
XMPP API Calls
3,000 calls /
32,000 calls /
XMPP Data Sent
22MB / min
740MB / min
XMPP Invitations Sent
XMPP is a fantastic new addition to the App Engine API. Google Talk users can chat
with the application or send notifications from the application to a Google Talk user
who is online. Chapter 9 covers a few of the more advanced topics around App