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From "cumtyjh" <cumt...@163.com>
Subject Re: Re: got Error: GC overhead limit exceeded when generate productsimilariy
Date Mon, 09 Nov 2009 04:31:04 GMT
thanks Sean Owen.

i have set jvm options like -Xmx2048m,no -server.


i want to generate item-item similarity offline, then i can use it for recommendation.


do you have some suggestion on generating item-item similarity offline?


2009-11-09 



cumtyjh 



发件人: Sean Owen 
发送时间: 2009-11-09  12:05:08 
收件人: mahout-user 
抄送: 
主题: Re: got Error: GC overhead limit exceeded when generate productsimilariy 
 
This basically means "out of heap space". It didn't technically run
out of memory, but, is triggering garbage collection so much that the
JVM figures it is critically low on free heap space.
You need to allocate more heap space. Try just 256MB with -Xm256m
Have you looked at the documentation, there are some other settings
you should be using with the JVM, like -server.
Also you don't need to create a GenericItemSimilarity. That is going
to consume a fair bit of memory as it is pre-computing and storing in
memory all item-item similarities from a Pearson correlation.
On Mon, Nov 9, 2009 at 2:28 AM, cumtyjh <cumtyjh@163.com> wrote:
> hi,all
>
> i got some error when generate product similarity according to rating file, and there
is about 250,000 recordes in rating file.
>
> it works when there is only 10,000 recordes in rating file.
>
>
> do you have some suggestion? any help is appreciated
>
> thanks in advance.
>
>
> following is code and log:
>
>
>  File file = new File(ratingFile);
>  logger.log(Level.INFO, "begin to load rating file...");
>  FileDataModel model = new FileDataModel(file);
>  logger.log(Level.INFO, "load rating file OK.");
> ItemSimilarity pearson = new LogLikelihoodSimilarity(model);
> GenericItemSimilarity gif = new GenericItemSimilarity(pearson,model);
>
>
>
> INFO: load rating file OK.
> - Reading file info...
> - Processed 100000 lines
> - Processed 200000 lines
> Exception in thread "Thread-9" java.lang.OutOfMemoryError: GC overhead limit exceeded
> at org.apache.mahout.cf.taste.impl.common.FastSet.<init>(FastSet.java:74)
> at org.apache.mahout.cf.taste.impl.model.GenericDataModel.getNumUsersWithPreferenceFor(GenericDataModel.java:195)
> at org.apache.mahout.cf.taste.impl.model.file.FileDataModel.getNumUsersWithPreferenceFor(FileDataModel.java:314)
> at org.apache.mahout.cf.taste.impl.similarity.LogLikelihoodSimilarity.itemSimilarity(LogLikelihoodSimilarity.java:48)
> at org.apache.mahout.cf.taste.impl.similarity.GenericItemSimilarity$DataModelSimilaritiesIterator.next(GenericItemSimilarity.java:291)
> at org.apache.mahout.cf.taste.impl.similarity.GenericItemSimilarity$DataModelSimilaritiesIterator.next(GenericItemSimilarity.java:260)
> at org.apache.mahout.cf.taste.impl.similarity.GenericItemSimilarity.initSimilarityMaps(GenericItemSimilarity.java:128)
> at org.apache.mahout.cf.taste.impl.similarity.GenericItemSimilarity.<init>(GenericItemSimilarity.java:103)
>
> 2009-11-09
>
>
>
> cumtyjh
>
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