The latest version has many bug fixes. You may be seeing such a bug. Sent from my iPhone
On Oct 19, 2011, at 2:27, WangRamon <[email protected]> wrote: > > Yes, I'm still using version 0.5, the plan is to verify it can work on 0.5 > and get some benchmark first then moving forward to 0.6, Sebastian, do you > think it's a problem related to Mahout? (Not Hadoop?) And do you think 0.6 > will bring us a huge performance increase? Thanks. CheersRamon >> Date: Wed, 19 Oct 2011 10:20:24 +0200 >> From: [email protected] >> To: [email protected] >> Subject: Re: Exception during running >> RowSimilarityJob-Mapper-EntriesToVectorsReducer job >> >> It seems like you're still not using Mahout 0.6. Please use the latest >> version and apply appropriate down sampling to your input data. You >> should also try to get access to a cluster with more than 2 machines. >> >> --sebastian >> >> On 19.10.2011 10:16, WangRamon wrote: >>> >>> >>> >>> >>> Hi Guys I'm continuing running the test case with a 1GB data file which >>> contains 600000 users and 2000000 items, all the jobs are running in a 2 >>> two nodes cluster, each node has 32GB RAM and 8 core CPU, the >>> RecommenderJob running until it reach >>> RowSimilarityJob-Mapper-EntriesToVectorsReducer Job, see below for the >>> error log: 11/10/18 23:09:34 INFO mapred.JobClient: map 11% reduce 1% >>> 11/10/18 23:12:46 INFO mapred.JobClient: map 11% reduce 2% >>> 11/10/18 23:13:55 INFO mapred.JobClient: map 12% reduce 2% >>> 11/10/18 23:18:22 INFO mapred.JobClient: map 13% reduce 2% >>> 11/10/18 23:22:50 INFO mapred.JobClient: map 14% reduce 2% >>> 11/10/18 23:27:08 INFO mapred.JobClient: map 15% reduce 2% >>> 11/10/18 23:28:15 INFO mapred.JobClient: map 15% reduce 3% >>> 11/10/18 23:31:42 INFO mapred.JobClient: map 16% reduce 3% >>> 11/10/18 23:33:36 INFO mapred.JobClient: Task Id : >>> attempt_201110181002_0007_r_000000_0, Status : FAILED >>> java.io.IOException: Task: attempt_201110181002_0007_r_000000_0 - The >>> reduce copier failed >>> at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:380) >>> at org.apache.hadoop.mapred.Child.main(Child.java:170) >>> Caused by: java.io.IOException: Intermediate merge failed >>> at >>> org.apache.hadoop.mapred.ReduceTask$ReduceCopier$InMemFSMergeThread.doInMemMerge(ReduceTask.java:2576) >>> at >>> org.apache.hadoop.mapred.ReduceTask$ReduceCopier$InMemFSMergeThread.run(ReduceTask.java:2501) >>> Caused by: java.lang.RuntimeException: java.io.EOFException >>> at >>> org.apache.hadoop.io.WritableComparator.compare(WritableComparator.java:103) >>> at org.apache.hadoop.mapred.Merger$MergeQueue.lessThan(Merger.java:373) >>> at org.apache.hadoop.util.PriorityQueue.upHeap(PriorityQueue.java:123) >>> at org.apache.hadoop.util.PriorityQueue.put(PriorityQueue.java:50) >>> at org.apache.hadoop.mapred.Merger$MergeQueue.merge(Merger.java:447) >>> at org.apache.hadoop.mapred.Merger$MergeQueue.merge(Merger.java:381) >>> at org.apache.hadoop.mapred.Merger.merge(Merger.java:107) >>> at org.apache.hadoop.mapred.Merger.merge(Merger.java:93) >>> at >>> org.apache.hadoop.mapred.ReduceTask$ReduceCopier$InMemFSMergeThread.doInMemMerge(ReduceTask.java:2551) >>> ... 1 more >>> Caused by: java.io.EOFException >>> at java.io.DataInputStream.readByte(DataInputStream.java:250) >>> at org.apache.mahout.math.Varint.readUnsignedVarInt(Varint.java:159) >>> at org.apache.mahout.math.Varint.readSignedVarInt(Varint.java:140) >>> at >>> org.apache.mahout.math.hadoop.similarity.SimilarityMatrixEntryKey.readFields(SimilarityMatrixEntryKey.java:64) >>> at >>> org.apache.hadoop.io.WritableComparator.compare(WritableComparator.java:97) >>> ... 9 more11/10/18 23:33:37 INFO mapred.JobClient: map 16% reduce 0% >>> 11/10/18 23:35:57 INFO mapred.JobClient: map 17% reduce 0% I googled a lot >>> and find i should increase "mapred.reduce.tasks" property in Hadoop, so I >>> set it to 8 in my environment and restart this Job only, so far so good, >>> the job is still running by now, but it's still a little slow, so here >>> comes my questions: 1) does it be so slow for this job >>> RowSimilarityJob-Mapper-EntriesToVectorsReducer Job ?2) what does this >>> property "mapred.reduce.tasks" do? And why it can effect >>> RowSimilarityJob-Mapper-EntriesToVectorsReducer Job ? (Maybe i should ask >>> this 2nd question in hadoop user list... but i think people here are both >>> pro at hadoop :) )3) what can i do to increase the speed for this job? Any >>> ideas? Thanks in advance! Ramon >> >
