On Sat, Jan 30, 2010 at 2:01 AM, Vinicius Carvalho <[email protected]> wrote: > Hello there! I'm trying to get Taste to work on the 10M dataset but, even > following some tips from Sean on Mahout in Action, I can't get it working > using SlopeOneRecommender and JDBC.
You are referring to the GroupLens data set right? > Caused by: java.lang.NullPointerException > at com.mysql.jdbc.ResultSetImpl.getLong(ResultSetImpl.java:2843) > at com.mysql.jdbc.ResultSetImpl.getLong(ResultSetImpl.java:2830) > at > org.apache.commons.dbcp.DelegatingResultSet.getLong(DelegatingResultSet.java:190) > at > org.apache.mahout.cf.taste.impl.model.jdbc.AbstractJDBCDataModel.getLongColumn(AbstractJDBCDataModel.java:602) That's odd, it's an error from the MySQL driver. I am taking a guess that one of the columns in the table had a null value? everything should be non-NULL. Or else... not sure, sounds like a driver bug? try the latest version 5.1.11. > I tried to replace the MemoryDiff by a JDBCDiff. After almost 1 hour running > the code, and 100% CPU usage by my mysql process. I decided to quit, is it > supposed to take so long? Depends on what you're doing -- what job are you running, computing recs for all users? Is your table indexed properly? that makes a huge difference. Why switch to JDBC? memory is a lot faster and seems like you have a lot of heap. That makes the driver issue a moot point. > > I tried to change the maxEntries to a smaller value but the NullPointer > always happens. My table is not exactly like the one used as sample on the > source code, but I do inform the correct columns and they are of the same > type.
