1. This limit is gone, but obviously the time it takes to do a query scales
with the result set. The design is actually quite easy: get back a cursor,
pass the cursor on the next iteration. I don't trivially say things are
easy; I err on the side of saying something is too complex.

2. Nope, not anymore.

You might want to look into something like appengine-mapreduce. In theory
you should be able to aggregate large numbers of entities into a few
blobstore (App Engine files API) entities:

http://code.google.com/p/appengine-mapreduce/

I say "in theory" because this tool is still experimental. We have every
intention of making this tool a core part of the platform but it isn't
there yet. Still, many developers are using this in production now for
offline computation:

http://googleappengine.blogspot.com/2010/08/practical-report-generation-on-app.html

--
Ikai Lan
Developer Programs Engineer, Google App Engine
plus.ikailan.com | twitter.com/ikai



On Wed, Dec 14, 2011 at 9:56 AM, Luca de Alfaro <[email protected]>wrote:

> We need to write an app/site whose general usage pattern matches quite
> well AppEngine, except for one thing: the site will be collecting data /
> logs, and every now and then, we need to download bulk data from the
> database tables collecting such data / logs, for offline analysis.
> If we went with a "non-appengine" solution, we could obviously do this by
> generating e.g. csv files from DB queries or dumps, and then processing the
> files.
> Will it be possible to have the same kind of simple access to bulk data on
> AppEngine?  We can of course build a (web) API that issues DB queries and
> produces csv files for download, but my concerns are:
>
>    1. I remember that there is a limit to how many records can be
>    extracted from a DB using a query (1000?), so that we would have to
>    implement the query with continuation parameters etc -- feasible, but
>    complicating the design.
>    2. I worry about the execution time of the query (is it still true
>    that processes taking over 1s are killed?).
>
> I guess access to log files / bulk data must be a pretty common
> requirement for many apps, so I am hoping someone has good words of
> advice...
> Many thanks!!
>
> Luca
>
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