In my experiment, if I do not call gc() explicitly, the shuffle files will not
be cleaned until the whole job finish… I don’t know why, maybe the rdd could
not be GCed implicitly.
In my situation, a full gc in driver takes about 10 seconds, so I start a
thread in driver to do GC like this : (do GC every 120 seconds)
while (true) {
System.gc();
Thread.sleep(120 * 1000);
}
it works well now.
Do you have more elegant ways to clean the shuffle files?
Best Regards,
Sendong Li
> 在 2015年4月1日，上午5:09，Xiangrui Meng <[email protected]> 写道：
>
> Hey Guoqiang and Sendong,
>
> Could you comment on the overhead of calling gc() explicitly? The shuffle
> files should get cleaned in a few seconds after checkpointing, but it is
> certainly possible to accumulates TBs of files in a few seconds. In this
> case, calling gc() may work the same as waiting for a few seconds after each
> checkpoint. Is it correct?
>
> Best,
> Xiangrui
>
> On Tue, Mar 31, 2015 at 8:58 AM, lisendong <[email protected]
> <mailto:[email protected]>> wrote:
> guoqiang ’s method works very well …
>
> it only takes 1TB disk now.
>
> thank you very much!
>
>
>
>> 在 2015年3月31日，下午4:47，GuoQiang Li <[email protected] <mailto:[email protected]>> 写道：
>>
>> You can try to enforce garbage collection:
>>
>> /** Run GC and make sure it actually has run */
>> def runGC() {
>> val weakRef = new WeakReference(new Object())
>> val startTime = System.currentTimeMillis
>> System.gc() // Make a best effort to run the garbage collection. It
>> *usually* runs GC.
>> // Wait until a weak reference object has been GCed
>> System.runFinalization()
>> while (weakRef.get != null) {
>> System.gc()
>> System.runFinalization()
>> Thread.sleep(200)
>> if (System.currentTimeMillis - startTime > 10000) {
>> throw new Exception("automatically cleanup error")
>> }
>> }
>> }
>>
>>
>> ------------------ 原始邮件 ------------------
>> 发件人: "lisendong"<[email protected] <mailto:[email protected]>>;
>> 发送时间: 2015年3月31日(星期二) 下午3:47
>> 收件人: "Xiangrui Meng"<[email protected] <mailto:[email protected]>>;
>> 抄送: "Xiangrui Meng"<[email protected] <mailto:[email protected]>>;
>> "user"<[email protected] <mailto:[email protected]>>; "Sean
>> Owen"<[email protected] <mailto:[email protected]>>; "GuoQiang
>> Li"<[email protected] <mailto:[email protected]>>;
>> 主题: Re: different result from implicit ALS with explicit ALS
>>
>> I have update my spark source code to 1.3.1.
>>
>> the checkpoint works well.
>>
>> BUT the shuffle data still could not be delete automatically…the disk usage
>> is still 30TB…
>>
>> I have set the spark.cleaner.referenceTracking.blocking.shuffle to true.
>>
>> Do you know how to solve my problem?
>>
>> Sendong Li
>>
>>
>>
>>> 在 2015年3月31日，上午12:11，Xiangrui Meng <[email protected]
>>> <mailto:[email protected]>> 写道：
>>>
>>> setCheckpointInterval was added in the current master and branch-1.3.
>>> Please help check whether it works. It will be included in the 1.3.1 and
>>> 1.4.0 release. -Xiangrui
>>>
>>> On Mon, Mar 30, 2015 at 7:27 AM, lisendong <[email protected]
>>> <mailto:[email protected]>> wrote:
>>> hi, xiangrui:
>>> I found the ALS of spark 1.3.0 forget to do checkpoint() in explicit ALS:
>>> the code is :
>>> https://github.com/apache/spark/blob/db34690466d67f9c8ac6a145fddb5f7ea30a8d8d/mllib/src/main/scala/org/apache/spark/ml/recommendation/ALS.scala
>>>
>>> <https://github.com/apache/spark/blob/db34690466d67f9c8ac6a145fddb5f7ea30a8d8d/mllib/src/main/scala/org/apache/spark/ml/recommendation/ALS.scala>
>>> <PastedGraphic-2.tiff>
>>>
>>> the checkpoint is very important in my situation, because my task will
>>> produce 1TB shuffle data in each iteration, it the shuffle data is not
>>> deleted in each iteration(using checkpoint()), the task will produce 30TB
>>> data…
>>>
>>>
>>> So I change the ALS code, and re-compile by myself, but it seems the
>>> checkpoint does not take effects, and the task still occupy 30TB disk… ( I
>>> only add two lines to the ALS.scala) :
>>>
>>> <PastedGraphic-3.tiff>
>>>
>>>
>>>
>>> and the driver’s log seems strange, why the log is printed together...
>>> <PastedGraphic-1.tiff>
>>>
>>> thank you very much!
>>>
>>>
>>>> 在 2015年2月26日，下午11:33，163 <[email protected] <mailto:[email protected]>> 写道：
>>>>
>>>> Thank you very much for your opinion:)
>>>>
>>>> In our case, maybe it 's dangerous to treat un-observed item as negative
>>>> interaction(although we could give them small confidence, I think they are
>>>> still incredible...)
>>>>
>>>> I will do more experiments and give you feedback:)
>>>>
>>>> Thank you;)
>>>>
>>>>
>>>>> 在 2015年2月26日，23:16，Sean Owen <[email protected]
>>>>> <mailto:[email protected]>> 写道：
>>>>>
>>>>> I believe that's right, and is what I was getting at. yes the implicit
>>>>> formulation ends up implicitly including every possible interaction in
>>>>> its loss function, even unobserved ones. That could be the difference.
>>>>>
>>>>> This is mostly an academic question though. In practice, you have
>>>>> click-like data and should be using the implicit version for sure.
>>>>>
>>>>> However you can give negative implicit feedback to the model. You
>>>>> could consider no-click as a mild, observed, negative interaction.
>>>>> That is: supply a small negative value for these cases. Unobserved
>>>>> pairs are not part of the data set. I'd be careful about assuming the
>>>>> lack of an action carries signal.
>>>>>
>>>>>> On Thu, Feb 26, 2015 at 3:07 PM, 163 <[email protected]
>>>>>> <mailto:[email protected]>> wrote:
>>>>>> oh my god, I think I understood...
>>>>>> In my case, there are three kinds of user-item pairs:
>>>>>>
>>>>>> Display and click pair(positive pair)
>>>>>> Display but no-click pair(negative pair)
>>>>>> No-display pair(unobserved pair)
>>>>>>
>>>>>> Explicit ALS only consider the first and the second kinds
>>>>>> But implicit ALS consider all the three kinds of pair(and consider the
>>>>>> third
>>>>>> kind as the second pair, because their preference value are all zero and
>>>>>> confidence are all 1)
>>>>>>
>>>>>> So the result are different. right?
>>>>>>
>>>>>> Could you please give me some advice, which ALS should I use?
>>>>>> If I use the implicit ALS, how to distinguish the second and the third
>>>>>> kind
>>>>>> of pair:)
>>>>>>
>>>>>> My opinion is in my case, I should use explicit ALS ...
>>>>>>
>>>>>> Thank you so much
>>>>>>
>>>>>> 在 2015年2月26日，22:41，Xiangrui Meng <[email protected]
>>>>>> <mailto:[email protected]>> 写道：
>>>>>>
>>>>>> Lisen, did you use all m-by-n pairs during training? Implicit model
>>>>>> penalizes unobserved ratings, while explicit model doesn't. -Xiangrui
>>>>>>
>>>>>>> On Feb 26, 2015 6:26 AM, "Sean Owen" <[email protected]
>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>
>>>>>>> +user
>>>>>>>
>>>>>>>> On Thu, Feb 26, 2015 at 2:26 PM, Sean Owen <[email protected]
>>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>>
>>>>>>>> I think I may have it backwards, and that you are correct to keep the 0
>>>>>>>> elements in train() in order to try to reproduce the same result.
>>>>>>>>
>>>>>>>> The second formulation is called 'weighted regularization' and is used
>>>>>>>> for both implicit and explicit feedback, as far as I can see in the
>>>>>>>> code.
>>>>>>>>
>>>>>>>> Hm, I'm actually not clear why these would produce different results.
>>>>>>>> Different code paths are used to be sure, but I'm not yet sure why they
>>>>>>>> would give different results.
>>>>>>>>
>>>>>>>> In general you wouldn't use train() for data like this though, and
>>>>>>>> would
>>>>>>>> never set alpha=0.
>>>>>>>>
>>>>>>>>> On Thu, Feb 26, 2015 at 2:15 PM, lisendong <[email protected]
>>>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>>>
>>>>>>>>> I want to confirm the loss function you use (sorry I’m not so familiar
>>>>>>>>> with scala code so I did not understand the source code of mllib)
>>>>>>>>>
>>>>>>>>> According to the papers :
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> in your implicit feedback ALS, the loss function is (ICDM 2008):
>>>>>>>>>
>>>>>>>>> in the explicit feedback ALS, the loss function is (Netflix 2008):
>>>>>>>>>
>>>>>>>>> note that besides the difference of confidence parameter Cui, the
>>>>>>>>> regularization is also different. does your code also has this
>>>>>>>>> difference?
>>>>>>>>>
>>>>>>>>> Best Regards,
>>>>>>>>> Sendong Li
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> 在 2015年2月26日，下午9:42，lisendong <[email protected]
>>>>>>>>>> <mailto:[email protected]>> 写道：
>>>>>>>>>>
>>>>>>>>>> Hi meng, fotero, sowen:
>>>>>>>>>>
>>>>>>>>>> I’m using ALS with spark 1.0.0, the code should be:
>>>>>>>>>>
>>>>>>>>>> https://github.com/apache/spark/blob/branch-1.0/mllib/src/main/scala/org/apache/spark/mllib/recommendation/ALS.scala
>>>>>>>>>>
>>>>>>>>>> <https://github.com/apache/spark/blob/branch-1.0/mllib/src/main/scala/org/apache/spark/mllib/recommendation/ALS.scala>
>>>>>>>>>>
>>>>>>>>>> I think the following two method should produce the same (or near)
>>>>>>>>>> result:
>>>>>>>>>>
>>>>>>>>>> MatrixFactorizationModel model = ALS.train(ratings.rdd(), 30, 30,
>>>>>>>>>> 0.01,
>>>>>>>>>> -1, 1);
>>>>>>>>>>
>>>>>>>>>> MatrixFactorizationModel model = ALS.trainImplicit(ratings.rdd(), 30,
>>>>>>>>>> 30, 0.01, -1, 0, 1);
>>>>>>>>>>
>>>>>>>>>> the data I used is display log, the format of log is as following:
>>>>>>>>>>
>>>>>>>>>> user item if-click
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I use 1.0 as score for click pair, and 0 as score for non-click pair.
>>>>>>>>>>
>>>>>>>>>> in the second method, the alpha is set to zero, so the confidence for
>>>>>>>>>> positive and negative are both 1.0 (right?)
>>>>>>>>>>
>>>>>>>>>> I think the two method should produce similar result, but the result
>>>>>>>>>> is
>>>>>>>>>> : the second method’s result is very bad (the AUC of the first
>>>>>>>>>> result is
>>>>>>>>>> 0.7, but the AUC of the second result is only 0.61)
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I could not understand why, could you help me?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Thank you very much!
>>>>>>>>>>
>>>>>>>>>> Best Regards,
>>>>>>>>>> Sendong Li
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>
>>>
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