And when retrieving only one supercolumn? Can I further specify which subcolumns to retrieve?
On Mon, Apr 19, 2010 at 9:29 PM, Jonathan Ellis <jbel...@gmail.com> wrote: > the latter, if you are retrieving multiple supercolumns. > > On Mon, Apr 19, 2010 at 8:10 PM, Joost Ouwerkerk <jo...@openplaces.org> > wrote: > > hmm, might be too much data. In the case of a supercolumn, how do I > specify > > which sub-columns to retrieve? Or can I only retrieve entire > supercolumns? > > On Mon, Apr 19, 2010 at 8:47 PM, Jonathan Ellis <jbel...@gmail.com> > wrote: > >> > >> Possibly you are asking it to retrieve too many columns per row. > >> > >> Possibly there is something else causing poor performance, like > swapping. > >> > >> On Mon, Apr 19, 2010 at 7:12 PM, Joost Ouwerkerk <jo...@openplaces.org> > >> wrote: > >> > I'm slowly getting somewhere with Cassandra... I have successfully > >> > imported > >> > 1.5 million rows using MapReduce. This took about 8 minutes on an > >> > 8-node > >> > cluster, which is comparable to the time it takes with HBase. > >> > Now I'm having trouble scanning this data. I've created a simple > >> > MapReduce > >> > job that counts rows in my ColumnFamily. The Job fails with most > tasks > >> > throwing the following Exception. Anyone have any ideas what's going > >> > wrong? > >> > java.lang.RuntimeException: TimedOutException() > >> > > >> > at > >> > > >> > > org.apache.cassandra.hadoop.ColumnFamilyRecordReader$RowIterator.maybeInit(ColumnFamilyRecordReader.java:165) > >> > at > >> > > >> > > org.apache.cassandra.hadoop.ColumnFamilyRecordReader$RowIterator.computeNext(ColumnFamilyRecordReader.java:215) > >> > at > >> > > >> > > org.apache.cassandra.hadoop.ColumnFamilyRecordReader$RowIterator.computeNext(ColumnFamilyRecordReader.java:97) > >> > at > >> > > >> > > com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:135) > >> > at > >> > > >> > > com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:130) > >> > at > >> > > >> > > org.apache.cassandra.hadoop.ColumnFamilyRecordReader.nextKeyValue(ColumnFamilyRecordReader.java:91) > >> > at > >> > > >> > > org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:423) > >> > at > >> > > org.apache.hadoop.mapreduce.MapContext.nextKeyValue(MapContext.java:67) > >> > at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:143) > >> > at > org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:583) > >> > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305) > >> > at org.apache.hadoop.mapred.Child.main(Child.java:170) > >> > Caused by: TimedOutException() > >> > at > >> > > >> > > org.apache.cassandra.thrift.Cassandra$get_range_slices_result.read(Cassandra.java:11015) > >> > at > >> > > >> > > org.apache.cassandra.thrift.Cassandra$Client.recv_get_range_slices(Cassandra.java:623) > >> > at > >> > > >> > > org.apache.cassandra.thrift.Cassandra$Client.get_range_slices(Cassandra.java:597) > >> > at > >> > > >> > > org.apache.cassandra.hadoop.ColumnFamilyRecordReader$RowIterator.maybeInit(ColumnFamilyRecordReader.java:142) > >> > ... 11 more > >> > > >> > On Sun, Apr 18, 2010 at 6:01 PM, Stu Hood <stu.h...@rackspace.com> > >> > wrote: > >> >> > >> >> In 0.6.0 and trunk, it is located at > >> >> src/java/org/apache/cassandra/hadoop/ColumnFamilyInputFormat.java > >> >> > >> >> You might be using a pre-release version of 0.6 if you are seeing a > fat > >> >> client based InputFormat. > >> >> > >> >> > >> >> -----Original Message----- > >> >> From: "Joost Ouwerkerk" <jo...@openplaces.org> > >> >> Sent: Sunday, April 18, 2010 4:53pm > >> >> To: user@cassandra.apache.org > >> >> Subject: Re: Help with MapReduce > >> >> > >> >> Where is the ColumnFamilyInputFormat that uses Thrift? I don't > >> >> actually > >> >> have a preference about client, I just want to be consistent with > >> >> ColumnInputFormat. > >> >> > >> >> On Sun, Apr 18, 2010 at 5:37 PM, Stu Hood <stu.h...@rackspace.com> > >> >> wrote: > >> >> > >> >> > ColumnFamilyInputFormat no longer uses the fat client API, and > >> >> > instead > >> >> > uses > >> >> > Thrift. There are still some significant problems with the fat > >> >> > client, > >> >> > so it > >> >> > shouldn't be used without a good understanding of those problems. > >> >> > > >> >> > If you still want to use it, check out contrib/bmt_example, but I'd > >> >> > recommend that you use thrift for now. > >> >> > > >> >> > -----Original Message----- > >> >> > From: "Joost Ouwerkerk" <jo...@openplaces.org> > >> >> > Sent: Sunday, April 18, 2010 2:59pm > >> >> > To: user@cassandra.apache.org > >> >> > Subject: Help with MapReduce > >> >> > > >> >> > I'm a Cassandra noob trying to validate Cassandra as a viable > >> >> > alternative > >> >> > to > >> >> > HBase (which we've been using for over a year) for our application. > >> >> > So > >> >> > far, > >> >> > I've had no success getting Cassandra working with MapReduce. > >> >> > > >> >> > My first step is inserting data into Cassandra. I've created a > >> >> > MapRed > >> >> > job > >> >> > based using the fat client API. I'm using the fat client > >> >> > (StorageProxy) > >> >> > because that's what ColumnFamilyInputFormat uses and I want to use > >> >> > the > >> >> > same > >> >> > API for both read and write jobs. > >> >> > > >> >> > When I call StorageProxy.mutate(), nothing happens. The job > >> >> > completes > >> >> > as > >> >> > if > >> >> > it had done something, but in fact nothing has changed in the > >> >> > cluster. > >> >> > When > >> >> > I call StorageProxy.mutateBlocking(), I get an IOException > >> >> > complaining > >> >> > that > >> >> > there is no connection to the cluster. I've concluded with the > >> >> > debugger > >> >> > that StorageService is not connecting to the cluster, even though > >> >> > I've > >> >> > specified the correct seed and ListenAddress (I've using the exact > >> >> > same > >> >> > storage-conf.xml as the nodes in the cluster). > >> >> > > >> >> > I'm sure I'm missing something obvious in the configuration or my > >> >> > setup, > >> >> > but > >> >> > since I'm new to Cassandra, I can't see what it is. > >> >> > > >> >> > Any help appreciated, > >> >> > Joost > >> >> > > >> >> > > >> >> > > >> >> > >> >> > >> > > >> > > > > > >
