Google AppEngine has made some great changes in version 1.3.1 that have caused some design decisions from regular apps to the cloud.

New Cursors Eliminate 1000 Row Limit in Datastore

Previously, developers could only easily get the first 1000-2000 rows of any query or filter easily.  This is because BigTable stores data in a way that fetching beyond that was difficult.  So if you wanted to get rows 3000-4000 or better yet 3010-3020 for a small page of data, you would have to devise a system to increment the rows previously and then have a marker to filter by that marker, then ensure they were in order.  It was troublesome and grew linearly in response times the deeper you needed to go.

With Cursors you can now put in a filter and page through the data, they seemingly encapsulated the difficult part of dealing with their cloud datastore structure and hopefully sped up the deep queried needed in such tools as logs, leaderboards, large lists and well, just about any web app now with any amount of data where you need to page deep.  And this will allow faster development of data applications for developers not used to cloud databases as most RDBMS have decent cursor/paging systems.

Wildcard Domains

If you are building a service where people get a username or where you want to shorten urls you can now use wildcard domains.  Domains like mybusiness.inventoryserviceapp.com instead of www.inventoryserviceapp.com/mybusinessapp.  It feels more personalized and is good for software as a service apps.  These are now possible on Google AppEngine.

You can use wildcards to map subdomains at any level, starting at third-level subdomains. For example, if your domain is example.com and you enter text in the web address field:

Entering * maps all subdomains of example.com to your app.

Entering *.private maps all subdomains of private.example.com to your app.

Entering *.nichol.sharks.nhl maps all subdomains of nichol.sharks.nhl.example.com to your app.

Entering *.excogitate.system maps all subdomains of excogitate.system.example.com to your app.

If you use Google Apps with other subdomains on your domain, such as sites and mail, those mappings have higher priority and are matched first, before any wildcard mapping takes place. In addition, if you have other App Engine apps mapped to other subdomains, those mappings also have higher priority than any wildcard mapping.

Note that some DNS providers might not work with wildcard subdomain mapping. In particular, a DNS provider must permit wildcards in CNAME host entries.

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Great changes in this update of the engine and built in a scalable way in the cloud.  As they refine and learn more about usage there will be more great changes making it less of a burden to move to the cloud, or better yet convincing others to move to Google AppEngine. Other stuff in this build that is great is the AppStats instrumentation apis, custom admin console and more…