> MongoDb doesn’t support Serializable interface. You're right. My mistake. Even if it was, Utf8 implementing Serializable isn't an option.
> I end up with a bunch of MongoResults instead of WebPages Are the WebPages "serialized" into Mongo, but not out of Mongo? Tyler On Fri, Oct 10, 2014 at 5:37 AM, Renato Marroquín Mogrovejo < renatoj.marroq...@gmail.com> wrote: > Hi guys, > > So I have just tried putting and getting elements (Nutch's WebPage) > entries specifically and everything works fine. So this is confusing, I > guess Nutch is doing something in the middle there that may have to do with > the mapping file or something like it. Because I tried changing the key > type (from String to Utf8) and gave an unrelated error saying that the > collection hadn't been defined (which is not true), I would have expected > to get a classCastException. And the other weird thing is that when > performing a get using a query object I end up with a bunch of MongoResults > instead of WebPages. I think that is bug (or . . . a feature) that we are > not aware of. Maybe Damian can help us out here. > I will keep on pocking around, but gora-mongodb is getting the data in, > and it is able to take it out. > > > Renato M. > > 2014-10-10 9:17 GMT+02:00 Kiril Menshikov <p...@kiril.me>: > >> Tyler, >> >> MongoDb doesn’t support Serializable interface. BasicBSONEncoder has >> direct class checks. Unfortunately it's not enough to make Utf8 >> serializable. >> >> -Kiril >> >> On Oct 9, 2014, at 21:44, Lewis John Mcgibbney <lewis.mcgibb...@gmail.com> >> wrote: >> >> > Hi Folks, >> > Whilst in the muddle of upgrading Nutch 2.3-SNAPSHOT to use Gora 0.5 >> we've run into a problem when implementing the gora-mongodb stuff. >> > The issue is described within the Jira issue [0]. This being said, >> Kiril (CC'd) has stated quite clearly why this is happening. This is a >> consequence of the following lines of the Nutch code base >> > >> > >> https://github.com/apache/nutch/blob/2.x/src/java/org/apache/nutch/fetcher/FetcherJob.java#L218 >> > >> > >> https://github.com/apache/nutch/blob/2.x/src/java/org/apache/nutch/parse/ParserJob.java#L274 >> > >> > >> https://github.com/apache/nutch/blob/2.x/src/java/org/apache/nutch/crawl/DbUpdaterJob.java#L128 >> > >> > and results in the following stack trace >> > java.lang.IllegalArgumentException: can't serialize class >> org.apache.avro.util.Utf8 >> > at org.bson.BasicBSONEncoder._putObjectField(BasicBSONEncoder.java:284) >> > at org.bson.BasicBSONEncoder.putObject(BasicBSONEncoder.java:185) >> > at org.bson.BasicBSONEncoder.putObject(BasicBSONEncoder.java:131) >> > at com.mongodb.DefaultDBEncoder.writeObject(DefaultDBEncoder.java:33) >> > at com.mongodb.OutMessage.putObject(OutMessage.java:289) >> > at com.mongodb.OutMessage.writeQuery(OutMessage.java:211) >> > at com.mongodb.OutMessage.query(OutMessage.java:86) >> > at com.mongodb.DBCollectionImpl.find(DBCollectionImpl.java:81) >> > at com.mongodb.DBCollectionImpl.find(DBCollectionImpl.java:66) >> > at com.mongodb.DBCursor._check(DBCursor.java:458) >> > at com.mongodb.DBCursor._hasNext(DBCursor.java:546) >> > at com.mongodb.DBCursor.hasNext(DBCursor.java:571) >> > at >> org.apache.gora.mongodb.query.MongoDBResult.nextInner(MongoDBResult.java:69) >> > at org.apache.gora.query.impl.ResultBase.next(ResultBase.java:114) >> > at >> org.apache.gora.mapreduce.GoraRecordReader.nextKeyValue(GoraRecordReader.java:119) >> > at >> org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:531) >> > at >> org.apache.hadoop.mapreduce.MapContext.nextKeyValue(MapContext.java:67) >> > at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144) >> > at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764) >> > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:364) >> > at >> org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:223) >> > at >> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) >> > at java.util.concurrent.FutureTask.run(FutureTask.java:262) >> > at >> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) >> > at >> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) >> > at java.lang.Thread.run(Thread.java:744) >> > >> > The cause is the following line (example from FetcherJob): >> > filter.getOperands().add(new Utf8(batchId)); >> > >> > During serialization MongoDB doesn't know about Utf8 type. >> > >> > My question is now... should we remove the Utf8 from Nutch, or should >> gora-mongodb handle this silently? >> > >> > Thanks for reading. >> > Lewis >> > >> > [0] https://issues.apache.org/jira/browse/NUTCH-1843 >> > >> > -- >> > Lewis >> >> >
