tree ab3ddbc4980dd30cd76a12b1b6773bd711fc830f
parent 7cbecd9f4571cc76c2a04470a78284f1485a433b
author Shawn O. Pearce <sop@google.com> 1231432209 -0800
committer Shawn O. Pearce <sop@google.com> 1231432308 -0800

Change backup to use GAE's new __key__ paging technique

Recently Google App Engine learned how to access the entity primary
key as part of the query's where clause, permitting range scans
by key.  This allows us to efficiently page the results and get
through all entities without making updates to them.

Unfortunately the change means its harder to resume if we abort,
as we don't have a way to pick up where we left off from.

Signed-off-by: Shawn O. Pearce <sop@google.com>