Yannick Richard wrote:
>
>
> Thomas Vandahl-2 wrote:
>>
>> Yannick Richard wrote:
>>> Hi,
>>>
>>>
>>>
>>> I am currently working on a Torque project that will handle database
>>> synchronization.
>>>
>>> The problem we have is an Out of Memory exception while selecting a big
>>> bunch of data from the database.
>>>
>>>
>>>
>>> Here is the command we are using :
>>>
>>> List ObjectsFromDB = ObjectPeer.doSelect(criteria, connection);
>>>
>>>
>>>
>>> I saw the LargeSelect class you worked on but cannot find any Java
>>> example that could help me go forward.
>>>
>>> Could you help me point to an example or help me understand how to
>>> integrate LargeSelect ?
>>
>> Just a few hints, I don't have a complete example at hand:
>>
>> LargeSelect ls = new LargeSelect(criteria, pageSize,
>> memoryPageLimit,
>> ObjectPeer.class.getName());
>>
>> where the pageSize defines how many records to get with one call and the
>> memoryPageLimit defines how many of these pages to "read ahead".
>>
>> With this object you can now loop through the pages and LargeSelect will
>> load the necessary data as needed, (pageSize * memoryPageLimit) records
>> at a time. Like:
>>
>> while (ls.getNextResultsAvailable())
>> {
>> List ObjectsFromDB = ls.getNextResults();
>> // do what is necessary
>> }
>>
>> See the JavaDoc at
>> http://db.apache.org/torque/releases/torque-3.3/runtime/apidocs/index.html
>> for more information.
>>
>> Bye, Thomas.
>>
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>>
>>
>>
>
> With your explanations I succeeded in running LargeSelect. It is now
> working while reading 10 000 records with a PageSize of 1000 and a
> MemoryPageLimit of 20. I don't know if it is normal, but when I use a
> MemoryPageLimit of 5 (5x1000 records), it is reading 1 - 5000 of 10000
> again and again and never get out of the loop...
>
> Next, I tried to use PageSize of 5000/MemoryPageLimit of 50 in order to
> read less than 250 000 records, I had following exception : Exception in
> thread "Thread-2" java.lang.OutOfMemoryError: Java heap space
>
> I then modified the Eclipse shortcut arguments to better manage Heap
> memory, etc :
> -vmargs -XX:+UseConcMarkSweepGC -XX:+CMSPermGenSweepingEnabled
> -XX:+CMSClassUnloadingEnabled -XX:MaxPermSize=256M -Xms128M -Xmx1024M
>
> Unfortunately, it jammed on first call of .getNextResults() for a night...
> When I debug it I can see that the Thread is sleeping in getResults(start,
> size) for all night on following command: while (((start + size - 1) >
> currentlyFilledTo) && !queryCompleted)
>
> Is this a memory problem or I did something wrong ?
>
> Regards,
> Yannick Richard
>
>
>
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