*In my store,have more than 100,000 entities here,but i find delete(limit
400) it's cost > 26s*
my datas is wrong so i must delete all entities of the kind(no index in the
kind)!
*1. first i use:*
Query q = pm.newQuery(query);
q.setRange(0, 400);
int count = 0;
try {
resultList = (List<T>) q.execute();
for (T t : resultList) {
pm.deletePersistent(t);
count++;
}
return count;
} finally {
q.closeAll();
}
I found that:every time it's delete only few entity(<100)!(I watch 200
entities of the kind with GAE Datastore Viewer)
*2 second i use:*
UtilGAE.howTimer(true),return how time cost with a threadlocal var store a
start millionseconds,arg is a flag(true if cost time>26second throw a
IllegalStateException("it's cost more than limit 26s");
DatastoreService ds = DatastoreServiceFactory.getDatastoreService();
Query query = new
Query(Section.class.getSimpleName()).setKeysOnly();
int count = 0;
try {
Iterable<Entity> iter =
ds.prepare(query).asIterable(FetchOptions.Builder.withLimit(400));
logger.info("query cost time：{}s",
UtilGAE.howTimer(true)/1000d);
for (Entity entity : iter) {
Key key = entity.getKey();
ds.delete(entity.getKey());
count++;
UtilGAE.howTimer(true);
}
if (count != 0) throw new IllegalStateException("next continue
to delete...");
} finally {
logger.info("delete：{},cost time:{}s", count,
UtilGAE.howTimer()/1000d);
}
so it's work fine(it's real delete entity from my store) and a most of cost
time in the 26s!
I say there have most of limited in the GAE Stored!you must to be carefull
when you have a larger datastore!
2010/3/12 Toby <[email protected]>
> Hello,
>
> deleting 500 should not take a lot of time. Did you try the
> deletePersistentAll method?
> Query q = pm.newQuery(persistentClass);
> q.deletePersistentAll();
>
> otherwise what I do is using the task queue. I delete 1000 entities
> and then put a task in the queue to delete another 1000. In that case
> you can not use the deletePersistentAll. You need to query by object
> type and limit:
>
> Query q = pm.newQuery(query);
> q.setRange(0, size);
>
> try {
> resultList = (List<T>) q.execute();
> resultSize = resultList.size();
> for (T t : resultList) {
> pm.deletePersistent(t);
> }
> return resultSize;
> } finally {
> q.closeAll();
> }
>
> since I return the size I see how much records where affected. If it
> is less than 1000 I know that I can stop doing the queuing.
> This is a bit difficult to set up but works fine. I believe there is
> not better way to do that but I am happy about any other suggestions.
>
> Cheers,
> Toby
>
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