Whoops, send with no content -- fumble-fingered.
On 4 April 2017 at 12:43, Chris Dollin <chris.dol...@epimorphics.com> wrote:
>
>
> On 4 April 2017 at 09:37, Chris Dollin <chris.dol...@epimorphics.com>
> wrote:
>
>> I ran a simplified version of the test code, with no
>> sort but with a limit, and could not produce warnings.
>>
>
Well of course not, it needs sort + small limit to involve TopN.
Chris
> So I'd not do anything to change TopN unless/until we
>> have more warnings to work with.
>>
>> Have we stabilised enough that I turn this into a JIRA/PR with
>> a unit test?
>>
>> Chris
>>
>>
>> On 3 April 2017 at 15:34, Chris Dollin <chris.dol...@epimorphics.com>
>> wrote:
>>
>>> Argh, yes, all occurences of "open()" are supposed
>>> to be "close()".
>>>
>>> | Have you seen warnings in the TopN case?
>>>
>>> I haven't got an isolated TopN test case but it has a similar
>>> pattern of keeping references to the source iterator but
>>> not closing via them.
>>>
>>> I can construct an example and see what happens.
>>>
>>> Chris
>>>
>>>
>>>
>>>
>>>
>>> On 3 April 2017 at 11:15, Andy Seaborne <a...@apache.org> wrote:
>>>
>>>>
>>>>
>>>> On 31/03/17 16:40, Chris Dollin wrote:
>>>>
>>>>> Hi Andy
>>>>>
>>>>> Yes, the cancel thread doesn't call open(), I understand
>>>>> that.
>>>>>
>>>>
>>>> is that "close()" not "open()"?
>>>>
>>>> The warnings are intermittent because the iterator
>>>>> in question (the "source" interator of QueryIterSort)
>>>>> is only left open if the cancel request is noticed while
>>>>> the sort databag is filling up.
>>>>>
>>>>> QueryIterSort never explicitly closes the source
>>>>> iterator. But if the sort databag pulls all of the
>>>>> source bindings, the source iterator self-closes.
>>>>> So there's a window while the bag is filling when
>>>>> a detected cancellation will leave the source
>>>>> iterator open.
>>>>>
>>>>> A fix is to ensure that the source iterator
>>>>> is closed when QueryIterSort closes:
>>>>>
>>>>> @Override public void closeIterator() {
>>>>>
>>>>
>>>> and also:
>>>>
>>>> this.db.close();
>>>>
>>>> c.f. requestCancel
>>>>
>>>> embeddedIterator.close();
>>>>> super.closeIterator();
>>>>> }
>>>>>
>>>>> "embeddedIterator" is the source iterator.
>>>>>
>>>>
>>>> SortedDataBag: add close() to cancel:
>>>>
>>>> public void cancel() {
>>>> comparator.cancel();
>>>> close();
>>>> }
>>>>
>>>>
>>>>
>>>>> This fix eliminates the presenting problem and
>>>>> the tests continue to pass /except/ that
>>>>> CallBackIterator's close() method needs to
>>>>> be made a no-op rather than failing, since
>>>>> that open() is now actually called.
>>>>>
>>>>
>>>> close()?
>>>>
>>>>
>>>>> [It looks like QueryIterTopN has the same problem]
>>>>>
>>>>
>>>> It would do no harm to have the same close processing in QueryIterTopN
>>>> though it does not use data bags because it is an unconditional single pass
>>>> over the data.
>>>>
>>>> Have you seen warnings in the TopN case?
>>>>
>>>> Andy
>>>>
>>>>
>>>>
>>>>> Chris
>>>>>
>>>>>
>>>>>
>>>>> On 20 March 2017 at 15:48, Chris Dollin <chris.dol...@epimorphics.com>
>>>>> wrote:
>>>>>
>>>>> On 17 March 2017 at 17:08, Andy Seaborne <a...@apache.org> wrote:
>>>>>>
>>>>>>
>>>>>>> SortedDataBag.cancel does not call close.
>>>>>>>
>>>>>>>
>>>>>> You're quite right, am having another look at the problem.
>>>>>>
>>>>>> Chris
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>> --
>>> "What I don't understand is this ..." Trevor Chaplin, /The Beiderbeck
>>> Affair/
>>>
>>> Epimorphics Ltd, http://www.epimorphics.com
>>> Registered address: Court Lodge, 105 High Street, Portishead, Bristol
>>> BS20 6PT
>>> Epimorphics Ltd. is a limited company registered in England (number
>>> 7016688)
>>>
>>
>>
>>
>> --
>> "What I don't understand is this ..." Trevor Chaplin, /The Beiderbeck
>> Affair/
>>
>> Epimorphics Ltd, http://www.epimorphics.com
>> Registered address: Court Lodge, 105 High Street, Portishead, Bristol
>> BS20 6PT
>> Epimorphics Ltd. is a limited company registered in England (number
>> 7016688)
>>
>
>
>
> --
> "What I don't understand is this ..." Trevor Chaplin, /The Beiderbeck
> Affair/
>
> Epimorphics Ltd, http://www.epimorphics.com
> Registered address: Court Lodge, 105 High Street, Portishead, Bristol BS20
> 6PT
> Epimorphics Ltd. is a limited company registered in England (number
> 7016688)
>
--
"What I don't understand is this ..." Trevor Chaplin, /The Beiderbeck
Affair/
Epimorphics Ltd, http://www.epimorphics.com
Registered address: Court Lodge, 105 High Street, Portishead, Bristol BS20
6PT
Epimorphics Ltd. is a limited company registered in England (number 7016688)
