hi,
I noticed on AppEngine dashboard at the Quata Details page that there is a high peak of Frontend Instance Hours. While going through the logs i noticed each client who has opened a page sends every 5 secs a Heartbeat message to the server. So I have used almost 30% of my daily Frontend Instance Quota in about 8 hours with 2 open clients that are just sitting there and doing nothing!!! I had just deployed the Vaadin wizard generated sample app to GAE…
It seems the heartbeat is a new feature of Vaadin7: ‘Heartbeat to reliably detect closed UI’
http://vaadin.com/download/release/7.0/7.0.2/release-notes.html
Therefore the question is, is Vaadin7 really intended to use on GAE or is it more a proof-of-concept / -technology thing?
because with a live application and even with multiple 100 of daily user the application won’t be payable on GAE…
Based on the answers, do you have any best practices for Vaadin7 + GAE?
thanks.
PS: the Book of Vaadin on section 11.7 Google App Engine Integration, constains the following statement:
"
Avoid (or be very careful when) updating application state in a TransactionListener …
"
However according the Vaadin API the TransactionListener class no longer exists in Vaadin7:
https://vaadin.com/api/7.0.2/index.html