Sorry for the trouble, I had trouble answering the original question
yesterday.
I twice replied by e-mail (from a Google Mail account ironically) but the
answers did not show up in the ArangoDB Google Group.
Thus I used the web interface to respond, but could not find the original
question. So I replied to another one of your questions.
Am Mittwoch, 29. Juni 2016 04:51:51 UTC+2 schrieb Thomas Weiss:
>
> Hi Jan,
>
> It seems that this is the exact same answer to an other issue I reported,
> but I don't think the issues are related.
>
> Thanks,
> Thomas
>
> On Tuesday, June 28, 2016 at 8:57:13 PM UTC+8, Jan wrote:
>>
>> Hi Thomas,
>>
>> I used your code to reproduce the issue and it's partly related.
>> The problem in this case is not that there are immutable objects, but
>> that the call to `byExample(...).count()` returns an unexpected value.
>>
>> var fromCount1 = db.foxxdebug.byExample({ _from: from, request: false }).
>> count();
>>
>> The `byExample()` returns an object of type `SimpleQueryByExample`, and
>> when calling `toArray()` on this, the results are correct, before and after
>> the update.
>> However, when calling `count()` on that object, this will also correctly
>> execute the simple query, but sometimes returns a wrong result for `count`.
>> The reason for this is that internally the result is produced by an index
>> lookup and then may need to be post-filtered in order to return only those
>> documents that match all conditions. In this case, the byExample will use
>> the edge index on `_from` and then post-filter the result using the
>> `request == false` condition. The result of post-filtering is also correct,
>> however, the `count` value of the query is not adjusted. `count` in this
>> case will return the number of documents before post-filtering.
>>
>> In your case the number of documents with the queried `_from` and `_to`
>> values don't change due to the replace, so the `count` values before and
>> after the replace are identical. Clearly it's a bug that the count value is
>> wrong, and I just fixed it in the 2.8 branch. I checked that it's already
>> working fine in 3.0, and 2.8 is the last affected version.
>>
>> By the way, the workaround to prevent the issue from occurring is to not
>> use `byExample(...).count()` but instead use
>> `byExample(...).toArray().length`.
>> We plan to build a new 2.8 release this week end.
>>
>> Best regards
>> Jan
>>
>> Am Freitag, 24. Juni 2016 15:11:53 UTC+2 schrieb Thomas Weiss:
>>>
>>> Hi there,
>>>
>>> I was debugging a different topic in my Foxx app and decided to give the
>>> 'allowImplicit' flag a try (to make sure that all the collections I read in
>>> my transactions were declared). But I found that, even if all collections
>>> are declared, adding this flag would raise an error. Here is a simple
>>> example to reproduce that (tested on 2.8.7):
>>>
>>> controller.post('/foxxdebug', function (req, res) {
>>> var from = 'foxxdebug/123';
>>> var to = 'foxxdebug/456';
>>> db._executeTransaction({
>>> collections: {
>>> read: ['foxxdebug'],
>>> write: ['foxxdebug'],
>>> allowImplicit: false
>>> },
>>> action: function () {
>>> db.foxxdebug.insert(from, to, {});
>>> var fromCount = db.foxxdebug.byExample({ _from: from }).
>>> count();
>>> var toCount = db.foxxdebug.byExample({ _to: to }).count();
>>> res.json({ fromCount: fromCount, toCount: toCount });
>>> }
>>> });
>>> });
>>>
>>> Note that the 'foxxdebug' was created, but this call would always fail
>>> with the 'unregistered collection used in transaction' error!
>>>
>>> Thomas
>>>
>>
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