老外还真不错，每次维护都是在太平洋时间的白天，刚好是北京时间的晚上12点后了，对我的所有应用形成不了冲击。估计老外没啥必须在晚上12点后加班的习惯，福利真是好。

似乎Google的所有服务都在晚上2点重启一下，Google Adsense是在北京时间15:00重新计算的，GAE后台也可以清楚看出在15:00左右服务器Reset了。


We’ve recently developed better visibility into our maintenance
schedule. This information isn’t perfect, but we’ve heard from many
developers that they’d like more advance notice from App Engine about
when these maintenance periods will occur. Therefore, we’re happy to
announce below the preliminary maintenance schedule for the rest of
2009:

- Tuesday, September 22nd, 5:00 PM Pacific Time
- Tuesday, November 3rd, 5:00 PM Pacific Time
- Tuesday, December 1st, 5:00 PM Pacific Time

We don’t expect this information to change, but if it does, we’ll
notify you (via the Downtime Notify Google Group) as soon as possible.
The App Engine team members are personally dedicated to keeping your
applications serving without interruption, and we realize that weekday
maintenance periods aren’t ideal for many. However, we’ve selected the
day of the week and time of day for maintenance to balance disruption
to App Engine developers with availability of the full engineering
teams of the services App Engine relies upon, like GFS and Bigtable.
In the coming months, we expect features like Megastore replication to
help reduce the length of our maintenance periods.

See more details here:
http://googleappengine.blogspot.com/2009/09/migration-to-better-datastore.html