53 seconds included the map phase to read and process the input file. The records were updated at the end of the reduce phase.
I checked the sales ranks in the update file and the sales ranks in the Cassandra, they are different and thus, the records were not actually updated. I remember I run the word count example for Cassandra 0.8.0 some time ago, I saw the similar behavior, i.e., the results were not written to the Cassandra column family. But If I changed hadoop to write to the file system, I can see the results in the output file. I didn't try the word count example for Cassandra 0.8.2 though. Anyway to solve this problem? Thanks, John On Thu, Aug 11, 2011 at 12:17 AM, aaron morton <aa...@thelastpickle.com>wrote: > I'm a simple guy. My first step would be see if the expected data is in the > data base, if not what's missing. > > 2.5M updates / 3 nodes = 833,333 per node > 833,333 / 53 seconds = 15,723 per second > 1 / 15,723 = 0.00006 seconds / 0.06 milliseconds per mutation > > sounds reasonable to me. > > check the Write Latency in nodetool cfstats and the row count estimates. > > Cheers > > ----------------- > Aaron Morton > Freelance Cassandra Developer > @aaronmorton > http://www.thelastpickle.com > > On 11 Aug 2011, at 14:50, Jian Fang wrote: > > There are data and each Cassandra cluster node holds about 100G. From the > application point of view, if I run the job twice with the same input file, > i.e., the sales rank update file, then I should see a much smaller number of > products, whose rank change exceeds the threshold, in the output file for > the second run because the sales ranks have been updated to be the same as > the ranks in the input file during the first run. But actually, I saw the > output files stay the same for the two runs. One explanation is that the > ranks were not actually updated for the first run. Also, 53 seconds to run > the whole hadoop job with 2.5 million Cassandra updates on three nodes, do > you think that is possible? Each node is a regular Linux box with 8 CPUs. > > Thanks, > > John > > On Wed, Aug 10, 2011 at 5:40 PM, aaron morton <aa...@thelastpickle.com>wrote: > >> Seems the data are not actually written to Cassandra. >> >> >> Before jumping into the Hadoop side of things are you saying there is no >> data in Cassandra ? Can you retrieve any using the CLI ? Take a look at >> cfstats on each node to see the estimated record count. >> >> Cheers >> >> ----------------- >> Aaron Morton >> Freelance Cassandra Developer >> @aaronmorton >> http://www.thelastpickle.com >> >> On 11 Aug 2011, at 08:20, Jian Fang wrote: >> >> Hi, >> >> I am using Cassandra 0.8.2 with Hadoop 0.20.2. My application read a file >> and then write about 2.5 million records >> to Cassandra. I used ColumnFamilyOutputFormat to write to Cassandra. My >> Cassandra cluster has three nodes with >> one Hadoop task tracker on each node. The wired problem is that I only saw >> one map and one reducer tasks and job only took >> 53 seconds to finish. Seems the data are not actually written to >> Cassandra. >> >> Here is status from Hadoop web admin: >> >> User: hadoop >> Job Name: SalesRankWriter >> Job File: >> hdfs://xxxxx:54310/hadoop/tmp/mapred/system/job_201108051329_0060/job.xml >> Job Setup: Successful >> Status: Succeeded >> Started at: Wed Aug 10 15:24:43 EDT 2011 >> Finished at: Wed Aug 10 15:25:36 EDT 2011 >> Finished in: 52sec >> Job Cleanup: Successful >> Kind % Complete Num Tasks Pending Running Complete Killed Failed/Killed >> Task Attempts >> map 100.00% >> 1 0 0 1 0 0 / 0 >> reduce 100.00% >> 1 0 0 1 0 0 / 0 >> >> Counter Map Reduce Total >> Job Counters Launched reduce tasks 0 0 1 >> Launched map tasks 0 0 1 >> Data-local map tasks 0 0 1 >> FileSystemCounters FILE_BYTES_READ 50,698,700 50,698,646 101,397,346 >> HDFS_BYTES_READ 56,149,360 0 56,149,360 >> FILE_BYTES_WRITTEN 101,397,378 50,698,646 152,096,024 >> Map-Reduce Framework Reduce input groups 0 2,534,932 2,534,932 >> Combine output records 0 0 0 >> Map input records 2,534,932 0 2,534,932 >> Reduce shuffle bytes 0 0 0 >> Reduce output records 0 2,534,932 2,534,932 >> Spilled Records 5,069,864 2,534,932 7,604,796 >> Map output bytes 45,628,776 0 45,628,776 >> Map output records 2,534,932 0 2,534,932 >> Combine input records 0 0 0 >> Reduce input records 0 2,534,932 2,534,932 >> >> and the log for the mapper >> >> 2011-08-10 15:24:48,717 INFO org.apache.hadoop.metrics.jvm.JvmMetrics: >> Initializing JVM Metrics with processName=MAP, sessionId= >> 2011-08-10 15:24:48,857 INFO org.apache.hadoop.mapred.MapTask: io.sort.mb >> = 100 2011-08-10 15:24:48,917 INFO org.apache.hadoop.mapred.MapTask: data >> buffer = 79691776/99614720 2011-08-10 15:24:48,917 INFO >> org.apache.hadoop.mapred.MapTask: record buffer = 262144/327680 2011-08-10 >> 15:24:49,760 INFO org.apache.hadoop.mapred.MapTask: Spilling map output: >> record full = true 2011-08-10 15:24:49,760 INFO >> org.apache.hadoop.mapred.MapTask: bufstart = 0; bufend = 4718592; bufvoid = >> 99614720 2011-08-10 15:24:49,760 INFO org.apache.hadoop.mapred.MapTask: >> kvstart = 0; kvend = 262144; length = 327680 2011-08-10 15:24:50,364 INFO >> org.apache.hadoop.mapred.MapTask: Finished spill 0 2011-08-10 15:24:50,707 >> INFO org.apache.hadoop.mapred.MapTask: Spilling map output: record full = >> true 2011-08-10 15:24:50,707 INFO org.apache.hadoop.mapred.MapTask: bufstart >> = 4718592; bufend = 9437166; bufvoid = 99614720 2011-08-10 15:24:50,707 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 262144; kvend = 196607; length = >> 327680 2011-08-10 15:24:51,238 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 1 2011-08-10 15:24:51,583 INFO >> org.apache.hadoop.mapred.MapTask: Spilling map output: record full = true >> 2011-08-10 15:24:51,583 INFO org.apache.hadoop.mapred.MapTask: bufstart = >> 9437166; bufend = 14155740; bufvoid = 99614720 2011-08-10 15:24:51,583 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 196607; kvend = 131070; length = >> 327680 2011-08-10 15:24:52,084 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 2 2011-08-10 15:24:52,433 INFO >> org.apache.hadoop.mapred.MapTask: Spilling map output: record full = true >> 2011-08-10 15:24:52,433 INFO org.apache.hadoop.mapred.MapTask: bufstart = >> 14155740; bufend = 18874314; bufvoid = 99614720 2011-08-10 15:24:52,433 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 131070; kvend = 65533; length = >> 327680 2011-08-10 15:24:52,877 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 3 2011-08-10 15:24:53,216 INFO >> org.apache.hadoop.mapred.MapTask: Spilling map output: record full = true >> 2011-08-10 15:24:53,216 INFO org.apache.hadoop.mapred.MapTask: bufstart = >> 18874314; bufend = 23592906; bufvoid = 99614720 2011-08-10 15:24:53,216 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 65533; kvend = 327677; length = >> 327680 2011-08-10 15:24:53,660 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 4 2011-08-10 15:24:54,010 INFO >> org.apache.hadoop.mapred.MapTask: Spilling map output: record full = true >> 2011-08-10 15:24:54,010 INFO org.apache.hadoop.mapred.MapTask: bufstart = >> 23592906; bufend = 28311480; bufvoid = 99614720 2011-08-10 15:24:54,010 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 327677; kvend = 262140; length = >> 327680 2011-08-10 15:24:54,447 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 5 2011-08-10 15:24:54,793 INFO >> org.apache.hadoop.mapred.MapTask: Spilling map output: record full = true >> 2011-08-10 15:24:54,793 INFO org.apache.hadoop.mapred.MapTask: bufstart = >> 28311480; bufend = 33030054; bufvoid = 99614720 2011-08-10 15:24:54,793 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 262140; kvend = 196603; length = >> 327680 2011-08-10 15:24:55,237 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 6 2011-08-10 15:24:55,564 INFO >> org.apache.hadoop.mapred.MapTask: Spilling map output: record full = true >> 2011-08-10 15:24:55,564 INFO org.apache.hadoop.mapred.MapTask: bufstart = >> 33030054; bufend = 37748628; bufvoid = 99614720 2011-08-10 15:24:55,564 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 196603; kvend = 131066; length = >> 327680 2011-08-10 15:24:55,981 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 7 2011-08-10 15:24:56,434 INFO >> org.apache.hadoop.mapred.MapTask: Spilling map output: record full = true >> 2011-08-10 15:24:56,434 INFO org.apache.hadoop.mapred.MapTask: bufstart = >> 37748628; bufend = 42467202; bufvoid = 99614720 2011-08-10 15:24:56,434 INFO >> org.apache.hadoop.mapred.MapTask: kvstart = 131066; kvend = 65529; length = >> 327680 2011-08-10 15:24:56,848 INFO org.apache.hadoop.mapred.MapTask: >> Finished spill 8 2011-08-10 15:24:57,051 INFO >> org.apache.hadoop.mapred.MapTask: Starting flush of map output 2011-08-10 >> 15:24:57,282 INFO org.apache.hadoop.mapred.MapTask: Finished spill 9 >> 2011-08-10 15:24:57,291 INFO org.apache.hadoop.mapred.Merger: Merging 10 >> sorted segments 2011-08-10 15:24:57,297 INFO >> org.apache.hadoop.mapred.Merger: Down to the last merge-pass, with 10 >> segments left of total size: 50698660 bytes 2011-08-10 15:24:59,552 INFO >> org.apache.hadoop.mapred.TaskRunner: >> Task:attempt_201108051329_0060_m_000000_0 is done. And is in the process of >> commiting 2011-08-10 15:24:59,555 INFO org.apache.hadoop.mapred.TaskRunner: >> Task 'attempt_201108051329_0060_m_000000_0' done. >> >> and the log for the reducer >> >> 2011-08-10 15:25:00,835 INFO org.apache.hadoop.metrics.jvm.JvmMetrics: >> Initializing JVM Metrics with processName=SHUFFLE, sessionId= 2011-08-10 >> 15:25:01,005 INFO org.apache.hadoop.mapred.ReduceTask: ShuffleRamManager: >> MemoryLimit=140699232, MaxSingleShuffleLimit=35174808 2011-08-10 >> 15:25:01,022 INFO org.apache.hadoop.mapred.ReduceTask: >> attempt_201108051329_0060_r_000000_0 Thread started: Thread for merging >> on-disk files 2011-08-10 15:25:01,022 INFO >> org.apache.hadoop.mapred.ReduceTask: attempt_201108051329_0060_r_000000_0 >> Thread started: Thread for merging in memory files 2011-08-10 15:25:01,022 >> INFO org.apache.hadoop.mapred.ReduceTask: >> attempt_201108051329_0060_r_000000_0 Thread waiting: Thread for merging >> on-disk files 2011-08-10 15:25:01,024 INFO >> org.apache.hadoop.mapred.ReduceTask: attempt_201108051329_0060_r_000000_0 >> Need another 1 map output(s) where 0 is already in progress 2011-08-10 >> 15:25:01,024 INFO org.apache.hadoop.mapred.ReduceTask: >> attempt_201108051329_0060_r_000000_0 Thread started: Thread for polling Map >> Completion Events 2011-08-10 15:25:01,037 INFO >> org.apache.hadoop.mapred.ReduceTask: attempt_201108051329_0060_r_000000_0 >> Scheduled 0 outputs (0 slow hosts and0 dup hosts) 2011-08-10 15:25:01,038 >> INFO org.apache.hadoop.mapred.ReduceTask: >> attempt_201108051329_0060_r_000000_0: Got 1 new map-outputs 2011-08-10 >> 15:25:06,039 INFO org.apache.hadoop.mapred.ReduceTask: >> attempt_201108051329_0060_r_000000_0 Scheduled 1 outputs (0 slow hosts and0 >> dup hosts) 2011-08-10 15:25:06,121 INFO org.apache.hadoop.mapred.ReduceTask: >> header: attempt_201108051329_0060_m_000000_0, compressed len: 50698646, >> decompressed len: 50698642 2011-08-10 15:25:06,121 INFO >> org.apache.hadoop.mapred.ReduceTask: Shuffling 50698642 bytes (50698646 raw >> bytes) into Local-FS from attempt_201108051329_0060_m_000000_0 2011-08-10 >> 15:25:06,314 INFO org.apache.hadoop.mapred.ReduceTask: Read 50698646 bytes >> from map-output for attempt_201108051329_0060_m_000000_0 2011-08-10 >> 15:25:06,315 INFO org.apache.hadoop.mapred.ReduceTask: >> attempt_201108051329_0060_r_000000_0 Thread waiting: Thread for merging >> on-disk files 2011-08-10 15:25:07,055 INFO >> org.apache.hadoop.mapred.ReduceTask: GetMapEventsThread exiting 2011-08-10 >> 15:25:07,055 INFO org.apache.hadoop.mapred.ReduceTask: getMapsEventsThread >> joined. 2011-08-10 15:25:07,056 INFO org.apache.hadoop.mapred.ReduceTask: >> Closed ram manager 2011-08-10 15:25:07,056 INFO >> org.apache.hadoop.mapred.ReduceTask: Interleaved on-disk merge complete: 1 >> files left. 2011-08-10 15:25:07,056 INFO >> org.apache.hadoop.mapred.ReduceTask: In-memory merge complete: 0 files left. >> 2011-08-10 15:25:07,061 INFO org.apache.hadoop.mapred.ReduceTask: Merging 1 >> files, 50698646 bytes from disk 2011-08-10 15:25:07,062 INFO >> org.apache.hadoop.mapred.ReduceTask: Merging 0 segments, 0 bytes from memory >> into reduce 2011-08-10 15:25:07,065 INFO org.apache.hadoop.mapred.Merger: >> Merging 1 sorted segments 2011-08-10 15:25:07,072 INFO >> org.apache.hadoop.mapred.Merger: Down to the last merge-pass, with 1 >> segments left of total size: 50698642 bytes 2011-08-10 15:25:30,126 INFO >> org.apache.hadoop.mapred.TaskRunner: >> Task:attempt_201108051329_0060_r_000000_0 is done. And is in the process of >> commiting 2011-08-10 15:25:30,129 INFO org.apache.hadoop.mapred.TaskRunner: >> Task 'attempt_201108051329_0060_r_000000_0' done. >> >> My code is similar to the word count example: >> >> public int run(String[] args) throws Exception { >> ... >> getConf().set(CONF_COLUMN_NAME, columnName); >> >> Job job4 = new Job(getConf(), "SalesRankWriter"); >> job4.setJarByClass(SalesRankLoader.class); >> job4.setMapperClass(RankUpdateMapper.class); >> job4.setReducerClass(RankUpdateReducer.class); >> job4.setMapOutputKeyClass(Text.class); >> job4.setMapOutputValueClass(IntWritable.class); >> job4.setOutputKeyClass(ByteBuffer.class); >> job4.setOutputValueClass(List.class); >> job4.setOutputFormatClass(ColumnFamilyOutputFormat.class); >> job4.setInputFormatClass(TextInputFormat.class); >> FileInputFormat.addInputPath(job4, new Path(prePath)); >> >> ConfigHelper.setOutputColumnFamily(job4.getConfiguration(), >> KEYSPACE, columnFamily); >> ConfigHelper.setRpcPort(job4.getConfiguration(), "9260"); >> ConfigHelper.setInitialAddress(job4.getConfiguration(), >> "dnjsrcha01"); >> ConfigHelper.setPartitioner(job4.getConfiguration(), >> "org.apache.cassandra.dht.RandomPartitioner"); >> >> job4.waitForCompletion(true); >> ... >> } >> >> where the mapper and reducer are defined as: >> >> public static class RankUpdateMapper extends Mapper<LongWritable, Text, >> Text, IntWritable> { public void map(LongWritable key, Text value, Context >> context) throws IOException, InterruptedException { String line = >> value.toString(); StringTokenizer tokenizer = new StringTokenizer(line); >> String ean = tokenizer.nextToken(); int rank = >> Integer.parseInt(tokenizer.nextToken()); context.write(new Text(ean), new >> IntWritable(rank)); } } public static class RankUpdateReducer extends >> Reducer<Text, IntWritable, ByteBuffer, List<Mutation>> { private ByteBuffer >> outputKey; protected void setup(org.apache.hadoop.mapreduce.Reducer.Context >> context) throws IOException, InterruptedException { outputKey = >> ByteBufferUtil.bytes(context.getConfiguration().get(CONF_COLUMN_NAME)); } >> public void reduce(Text key, Iterable<IntWritable> values, Context context) >> throws IOException, InterruptedException { context.write(outputKey, >> Collections.singletonList(getMutation(key, >> values.iterator().next().get()))); } private static Mutation >> getMutation(Text key, int value) { Column c = new Column(); >> c.setName(ByteBuffer.wrap(Arrays.copyOf(key.getBytes(), key.getLength()))); >> c.setValue(ByteBufferUtil.bytes(String.valueOf(value))); >> c.setTimestamp(System.currentTimeMillis() * 1000); Mutation m = new >> Mutation(); m.setColumn_or_supercolumn(new ColumnOrSuperColumn()); >> m.column_or_supercolumn.setColumn(c); return m; } } >> >> Any thing wrong here? >> >> Thanks, >> >> John >> >> >> > >
