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From Josh Wills <jwi...@cloudera.com>
Subject Re: Multiple Reduces in a Single Crunch Job
Date Wed, 26 Nov 2014 01:43:52 GMT
Drat, I was hoping it was something simple. You could manually fix it by
injecting a pipeline.run() call between the secondarySort and the
groupByKey(), but of course, we'd like to handle this situation correctly
by default.

J

On Tue, Nov 25, 2014 at 5:39 PM, Danny Morgan <unluckyboy@hotmail.com>
wrote:

> I did a parallelDo with the IdentityFn of the output of the secondarySort
> and the IdentityFn was just fused into the reduce phase of the
> secondarySort and I got the same error message.
>
> I think you want me to somehow force a map phase in between the two
> reduces?
>
> -Danny
>
> ------------------------------
> From: josh.wills@gmail.com
> Date: Tue, 25 Nov 2014 17:23:29 -0800
>
> Subject: Re: Multiple Reduces in a Single Crunch Job
> To: user@crunch.apache.org
>
> Oh, dumb question-- if you put like a dummy function between the
> secondarySort and the groupByKey, like an IdentityFn or something, do
> things work again? That would help w/diagnosing the problem.
>
> On Tue, Nov 25, 2014 at 5:15 PM, Josh Wills <jwills@cloudera.com> wrote:
>
> So if you're getting it quickly, it might be b/c the job isn't recognizing
> the dependency between the two separate phases of the job for some reason
> (e.g., it's not realizing that one job has to be run before the other one.)
> That's an odd situation, but we have had bugs like that in the past; let me
> see if I can re-create the situation in an integration test. Which version
> of Crunch?
>
> J
>
> On Tue, Nov 25, 2014 at 4:40 PM, Danny Morgan <unluckyboy@hotmail.com>
> wrote:
>
> No that's definitely not it. I get this issue if I write to a single
> output as well.
>
> If I remove the groupByKey().combineValues() line and just write out the
> output from the SecondarySort it works. Seems to only complain about the
> temp path not existing when I have multiple reduce phases in the pipeline.
> Also the error seems to happen immediately during the setup or planning
> phase, I assume this because the yarn jobs get created but they don't do
> anything, and instead of FAILED the error message is "Application killed by
> user."
>
> -Danny
>
> ------------------------------
> From: jwills@cloudera.com
> Date: Tue, 25 Nov 2014 16:30:58 -0800
>
> Subject: Re: Multiple Reduces in a Single Crunch Job
> To: user@crunch.apache.org
>
> Ack, sorry-- it's this: https://issues.apache.org/jira/browse/CRUNCH-481
> <https://issues.apache.org/jira/browse/CRUNCH-481-->
>
> On Tue, Nov 25, 2014 at 4:24 PM, Danny Morgan <unluckyboy@hotmail.com>
> wrote:
>
> Hello Again Josh,
>
> The link to the Jira issue you sent out seems to be cut off, could you
> please resend it?
>
> I deleted the line where I write the collection to a text file, and
> retried it but it didn't work either. Also tried writing the collection out
> as Avro instead of Parquet, but got the same error.
>
> Here's the rest of the stracktrace:
>
> org.apache.hadoop.mapreduce.lib.input.InvalidInputException: Input path
> does not exist: hdfs:///tmp/crunch-2008950085/p1
>         at
> org.apache.hadoop.mapreduce.lib.input.FileInputFormat.listStatus(FileInputFormat.java:285)
>         at
> org.apache.hadoop.mapreduce.lib.input.CombineFileInputFormat.getSplits(CombineFileInputFormat.java:217)
>         at
> org.apache.crunch.impl.mr.run.CrunchInputFormat.getSplits(CrunchInputFormat.java:65)
>         at
> org.apache.hadoop.mapreduce.JobSubmitter.writeNewSplits(JobSubmitter.java:491)
>         at
> org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:508)
>         at
> org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:392)
>         at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1268)
>         at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1265)
>         at java.security.AccessController.doPrivileged(Native Method)
>         at javax.security.auth.Subject.doAs(Subject.java:415)
>         at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1528)
>         at org.apache.hadoop.mapreduce.Job.submit(Job.java:1265)
>         at
> org.apache.crunch.hadoop.mapreduce.lib.jobcontrol.CrunchControlledJob.submit(CrunchControlledJob.java:340)
>         at
> org.apache.crunch.hadoop.mapreduce.lib.jobcontrol.CrunchJobControl.startReadyJobs(CrunchJobControl.java:277)
>         at
> org.apache.crunch.hadoop.mapreduce.lib.jobcontrol.CrunchJobControl.pollJobStatusAndStartNewOnes(CrunchJobControl.java:316)
>         at
> org.apache.crunch.impl.mr.exec.MRExecutor.monitorLoop(MRExecutor.java:113)
>         at
> org.apache.crunch.impl.mr.exec.MRExecutor.access$000(MRExecutor.java:55)
>         at
> org.apache.crunch.impl.mr.exec.MRExecutor$1.run(MRExecutor.java:84)
>         at java.lang.Thread.run(Thread.java:744)
>
> Thanks Josh!
>
> ------------------------------
> From: jwills@cloudera.com
> Date: Tue, 25 Nov 2014 16:10:33 -0800
> Subject: Re: Multiple Reduces in a Single Crunch Job
> To: user@crunch.apache.org
>
>
> Hey Danny,
>
> I'm wondering if this is caused by
> https://issues.apache.org/jira/browse/CRUNCH-481-- I think we use
> different output committers for text files vs. parquet files, so at least
> one of the outputs won't be written properly-- does that make sense?
>
> Josh
>
> On Tue, Nov 25, 2014 at 4:07 PM, Danny Morgan <unluckyboy@hotmail.com>
> wrote:
>
> Hi Crunchers,
>
> I've attached a pdf of what my plan looks like. I've run into this problem
> before where I have multiple reduce steps chained together in a single
> pipeline and always get the same error.
>
> In the case of the attached pdf the error is "org.apache.hadoop.mapreduce.lib.input.InvalidInputException:
> Input path does not exist: hdfs:///tmp/crunch-1279941375/p1"
>
> That's the temp directory the crunch planner set up for the first reduce
> phase.
>
> Can I run multiple chained reduces within the same pipeline? Do I have to
> manually write out the output from the first reduce?
>
> Here's what the code looks like:
>
>       // Simple mapper
>       PTable<String, Pair<Long, Log>> first = Danny.filterForDanny(logs);
>       // Secondary sort happens here
>       PTable<Danny, Long> second = Danny.extractDannys(first);
>       // Regular group by
>       PTable<Danny, Long> third =
> second.groupByKey().combineValues(Aggregators.SUM_LONGS());
>       // simple function that populates some fields in the Danny object
> with the aggregate results
>       PCollection<Pair<Danny, String>> done = Danny.finalize(third);
>       Pair<PCollection<Danny>, PCollection<String>> splits =
> Channels.split(done);
>       splits.second().write(To.textFile(mypath, WriteMode.OVERWRITE);
>       Target pq_danny = new AvroParquetFileTarget(pqPath));
>       splits.first().write(pq_danny, WriteMode.OVERWRITE)
>
> Thanks!
>
> -Danny
>
>
>
>
> --
> Director of Data Science
> Cloudera <http://www.cloudera.com>
> Twitter: @josh_wills <http://twitter.com/josh_wills>
>
>
>
>
> --
> Director of Data Science
> Cloudera <http://www.cloudera.com>
> Twitter: @josh_wills <http://twitter.com/josh_wills>
>
>
>
>
> --
> Director of Data Science
> Cloudera <http://www.cloudera.com>
> Twitter: @josh_wills <http://twitter.com/josh_wills>
>
>
>


-- 
Director of Data Science
Cloudera <http://www.cloudera.com>
Twitter: @josh_wills <http://twitter.com/josh_wills>

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