Thanks Peter - i think i'm forced to use a query like the one above
because the only criteria i have for deleting these objects is a
timestamp and the foreign key. So I would have to make a seperate
query to get the object's keys. Please let me know if i'm missing some
trick here or if it makes sense to do this another way
It looks like the only solution that isn't causing errors is to delete
1000 at a time and then restart the delete task until the result is
zero. This is all very expensive though, it looks like it costs about
$2.00 to delete a couple hundred thousand records this way.
The big question is, is it the deletePersistentAll that's costing the
cpu time? Should i get the query and iterate through the result and
use the low level api to delete each key?
Here is what i currently have that is costing a lot of $ to purge a
couple 100K of records from the database
Query q = pm.newQuery(RecordedValue.class,"pointFK== k
&& timestamp
< d");
q.declareImports("import java.util.Date");
q.setRange(0,1000);
q.setOrdering("timestamp ascending");
Map<String, Object> args = new HashMap<String,
Object>();
args.put("k",pointId);
args.put("d", d.getTime());
List<RecordedValue> v = (List<RecordedValue>)
q.executeWithMap(args);
long count = v.size();
if (count > 0)
{
pm.deletePersistentAll(v);
DataServiceImpl.startDeleteDataTask(pointId,true,expDays);
}
On Feb 12, 1:57 pm, Peter Liu <tinyee...@gmail.com> wrote:
> Try using the low level API and do keys only query with limit of 1000
> (and delete them) repeatedly instead of retrieving whole objects.
>
> I am guessing the out of memory is due to large amount of objects
> returned by the query. Keys only query also use much less api cpu.
>
> On Feb 12, 9:22 pm, Benjamin <bsaut...@gmail.com> wrote:
>
>
>
>
>
>
>
> > I'm getting errors when a task kicks off to delete a lot of data based
> > on a timestamp. I enabled billing and already chewed through $0.50 in
> > CPU time, but i'm still getting the error message. Is there anything
> > else I should do? I was trying to avoid splitting the task up with a
> > result limit or something, i really just need to blow away persisted
> > objects that have a timestamp older than a specified date - this
> > snippet of code causes the error:
>
> > PersistenceManager pm = PMF.get().getPersistenceManager();
> > Calendar d = Calendar.getInstance();
> > long retVal = 0;
> > if (expDays > 0)
> > {
> > d.add(Calendar.DATE,(expDays * -1));
> > Query q =
> > pm.newQuery(RecordedValue.class,"pointFK== k && timestamp
> > < d");
> > q.declareImports("import java.util.Date");
> > Map<String, Object> args = new HashMap<String,
> > Object>();
> > args.put("k",pointId);
> > args.put("d", d.getTime());
> > retVal = q.deletePersistentAll(args);
>
> > }
> > pm.close();
> > return retVal;
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