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Posted to mapreduce-user@hadoop.apache.org by Fengyun RAO <ra...@gmail.com> on 2014/03/06 09:09:00 UTC
MapReduce: How to output multiplt Avro files?
our input is a line of text which may be parsed to e.g. A or B object.
We want all A objects written to "A.avro" files, while all B objects
written to "B.avro".
I looked into AvroMultipleOutputs class:
http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
There is an example, however, it's not quite clear.
For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
schemas for A and B.
In my program looks like:
AvroMultipleOutputs.addNamedOutput(job, "A",
AvroKeyOutputFormat.class, aSchema, null);
AvroMultipleOutputs.addNamedOutput(job, "B",
AvroKeyOutputFormat.class, bSchema, null);
I believe this is for Reducer output files.
*My question is* what the Mapper output should be, in specific what
"job.setMapOutputValueClass" should be,
since the Mapper output could be A or B object, with schema aSchema or
bSchema.
In my progam, I simply set it to GenericData, but get error as below:
14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
attempt_1393817780522_0012_m_000010_2, Status : FAILED
Error: java.lang.NullPointerException
at
org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
at
org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
at
org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
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:1491)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
I have no idea what this means.
RE: MapReduce: How to output multiplt Avro files?
Posted by java8964 <ja...@hotmail.com>.
You may consider "SpecificRecord" or "GenericRecord" of Avor.
Yong
Date: Fri, 7 Mar 2014 10:29:49 +0800
Subject: Re: MapReduce: How to output multiplt Avro files?
From: raofengyun@gmail.com
To: user@hadoop.apache.org; harsh@cloudera.com
thanks, Harsh.
any idea on how to build a common map output data type? The only way I can think of is "toString()", which would be very inefficient, since A and B are big objects and may change with time, which is also the reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> 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:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J
RE: MapReduce: How to output multiplt Avro files?
Posted by java8964 <ja...@hotmail.com>.
You may consider "SpecificRecord" or "GenericRecord" of Avor.
Yong
Date: Fri, 7 Mar 2014 10:29:49 +0800
Subject: Re: MapReduce: How to output multiplt Avro files?
From: raofengyun@gmail.com
To: user@hadoop.apache.org; harsh@cloudera.com
thanks, Harsh.
any idea on how to build a common map output data type? The only way I can think of is "toString()", which would be very inefficient, since A and B are big objects and may change with time, which is also the reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> 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:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J
RE: MapReduce: How to output multiplt Avro files?
Posted by java8964 <ja...@hotmail.com>.
You may consider "SpecificRecord" or "GenericRecord" of Avor.
Yong
Date: Fri, 7 Mar 2014 10:29:49 +0800
Subject: Re: MapReduce: How to output multiplt Avro files?
From: raofengyun@gmail.com
To: user@hadoop.apache.org; harsh@cloudera.com
thanks, Harsh.
any idea on how to build a common map output data type? The only way I can think of is "toString()", which would be very inefficient, since A and B are big objects and may change with time, which is also the reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> 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:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J
RE: MapReduce: How to output multiplt Avro files?
Posted by java8964 <ja...@hotmail.com>.
You may consider "SpecificRecord" or "GenericRecord" of Avor.
Yong
Date: Fri, 7 Mar 2014 10:29:49 +0800
Subject: Re: MapReduce: How to output multiplt Avro files?
From: raofengyun@gmail.com
To: user@hadoop.apache.org; harsh@cloudera.com
thanks, Harsh.
any idea on how to build a common map output data type? The only way I can think of is "toString()", which would be very inefficient, since A and B are big objects and may change with time, which is also the reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> 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:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J
Re: MapReduce: How to output multiplt Avro files?
Posted by Fengyun RAO <ra...@gmail.com>.
thanks, Harsh.
any idea on how to build a common map output data type?
The only way I can think of is "toString()", which would be very
inefficient,
since A and B are big objects and may change with time, which is also the
reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
> If you have a reducer involved, you'll likely need a common map output
> data type that both A and B can fit into.
>
> On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> > our input is a line of text which may be parsed to e.g. A or B object.
> > We want all A objects written to "A.avro" files, while all B objects
> written
> > to "B.avro".
> >
> > I looked into AvroMultipleOutputs class:
> >
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> > There is an example, however, it's not quite clear.
> > For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> > schemas for A and B.
> > In my program looks like:
> > AvroMultipleOutputs.addNamedOutput(job, "A",
> > AvroKeyOutputFormat.class, aSchema, null);
> > AvroMultipleOutputs.addNamedOutput(job, "B",
> > AvroKeyOutputFormat.class, bSchema, null);
> > I believe this is for Reducer output files.
> >
> > My question is what the Mapper output should be, in specific what
> > "job.setMapOutputValueClass" should be,
> > since the Mapper output could be A or B object, with schema aSchema or
> > bSchema.
> >
> > In my progam, I simply set it to GenericData, but get error as below:
> >
> > 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> > attempt_1393817780522_0012_m_000010_2, Status : FAILED
> > Error: java.lang.NullPointerException
> > at
> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> > at
> > org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> > at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> > at
> >
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> > at
> org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> > at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> > 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:1491)
> > at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
> >
> > I have no idea what this means.
>
>
>
> --
> Harsh J
>
Re: MapReduce: How to output multiplt Avro files?
Posted by Fengyun RAO <ra...@gmail.com>.
thanks, Harsh.
any idea on how to build a common map output data type?
The only way I can think of is "toString()", which would be very
inefficient,
since A and B are big objects and may change with time, which is also the
reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
> If you have a reducer involved, you'll likely need a common map output
> data type that both A and B can fit into.
>
> On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> > our input is a line of text which may be parsed to e.g. A or B object.
> > We want all A objects written to "A.avro" files, while all B objects
> written
> > to "B.avro".
> >
> > I looked into AvroMultipleOutputs class:
> >
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> > There is an example, however, it's not quite clear.
> > For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> > schemas for A and B.
> > In my program looks like:
> > AvroMultipleOutputs.addNamedOutput(job, "A",
> > AvroKeyOutputFormat.class, aSchema, null);
> > AvroMultipleOutputs.addNamedOutput(job, "B",
> > AvroKeyOutputFormat.class, bSchema, null);
> > I believe this is for Reducer output files.
> >
> > My question is what the Mapper output should be, in specific what
> > "job.setMapOutputValueClass" should be,
> > since the Mapper output could be A or B object, with schema aSchema or
> > bSchema.
> >
> > In my progam, I simply set it to GenericData, but get error as below:
> >
> > 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> > attempt_1393817780522_0012_m_000010_2, Status : FAILED
> > Error: java.lang.NullPointerException
> > at
> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> > at
> > org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> > at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> > at
> >
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> > at
> org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> > at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> > 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:1491)
> > at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
> >
> > I have no idea what this means.
>
>
>
> --
> Harsh J
>
Re: MapReduce: How to output multiplt Avro files?
Posted by Fengyun RAO <ra...@gmail.com>.
thanks, Harsh.
any idea on how to build a common map output data type?
The only way I can think of is "toString()", which would be very
inefficient,
since A and B are big objects and may change with time, which is also the
reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
> If you have a reducer involved, you'll likely need a common map output
> data type that both A and B can fit into.
>
> On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> > our input is a line of text which may be parsed to e.g. A or B object.
> > We want all A objects written to "A.avro" files, while all B objects
> written
> > to "B.avro".
> >
> > I looked into AvroMultipleOutputs class:
> >
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> > There is an example, however, it's not quite clear.
> > For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> > schemas for A and B.
> > In my program looks like:
> > AvroMultipleOutputs.addNamedOutput(job, "A",
> > AvroKeyOutputFormat.class, aSchema, null);
> > AvroMultipleOutputs.addNamedOutput(job, "B",
> > AvroKeyOutputFormat.class, bSchema, null);
> > I believe this is for Reducer output files.
> >
> > My question is what the Mapper output should be, in specific what
> > "job.setMapOutputValueClass" should be,
> > since the Mapper output could be A or B object, with schema aSchema or
> > bSchema.
> >
> > In my progam, I simply set it to GenericData, but get error as below:
> >
> > 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> > attempt_1393817780522_0012_m_000010_2, Status : FAILED
> > Error: java.lang.NullPointerException
> > at
> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> > at
> > org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> > at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> > at
> >
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> > at
> org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> > at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> > 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:1491)
> > at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
> >
> > I have no idea what this means.
>
>
>
> --
> Harsh J
>
Re: MapReduce: How to output multiplt Avro files?
Posted by Fengyun RAO <ra...@gmail.com>.
thanks, Harsh.
any idea on how to build a common map output data type?
The only way I can think of is "toString()", which would be very
inefficient,
since A and B are big objects and may change with time, which is also the
reason we want to use Avro serialization.
2014-03-07 9:55 GMT+08:00 Harsh J <ha...@cloudera.com>:
> If you have a reducer involved, you'll likely need a common map output
> data type that both A and B can fit into.
>
> On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> > our input is a line of text which may be parsed to e.g. A or B object.
> > We want all A objects written to "A.avro" files, while all B objects
> written
> > to "B.avro".
> >
> > I looked into AvroMultipleOutputs class:
> >
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> > There is an example, however, it's not quite clear.
> > For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> > schemas for A and B.
> > In my program looks like:
> > AvroMultipleOutputs.addNamedOutput(job, "A",
> > AvroKeyOutputFormat.class, aSchema, null);
> > AvroMultipleOutputs.addNamedOutput(job, "B",
> > AvroKeyOutputFormat.class, bSchema, null);
> > I believe this is for Reducer output files.
> >
> > My question is what the Mapper output should be, in specific what
> > "job.setMapOutputValueClass" should be,
> > since the Mapper output could be A or B object, with schema aSchema or
> > bSchema.
> >
> > In my progam, I simply set it to GenericData, but get error as below:
> >
> > 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> > attempt_1393817780522_0012_m_000010_2, Status : FAILED
> > Error: java.lang.NullPointerException
> > at
> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> > at
> > org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> > at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> > at
> >
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> > at
> org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> > at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> > at java.security.AccessController.doPrivileged(Native Method)
> > at javax.security.auth.Subject.doAs(Subject.java:415)
> > at
> >
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
> > at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
> >
> > I have no idea what this means.
>
>
>
> --
> Harsh J
>
Re: MapReduce: How to output multiplt Avro files?
Posted by Harsh J <ha...@cloudera.com>.
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:415)
> at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J
Re: MapReduce: How to output multiplt Avro files?
Posted by Harsh J <ha...@cloudera.com>.
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:415)
> at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J
Re: MapReduce: How to output multiplt Avro files?
Posted by Harsh J <ha...@cloudera.com>.
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:415)
> at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J
Re: MapReduce: How to output multiplt Avro files?
Posted by Harsh J <ha...@cloudera.com>.
If you have a reducer involved, you'll likely need a common map output
data type that both A and B can fit into.
On Thu, Mar 6, 2014 at 12:09 AM, Fengyun RAO <ra...@gmail.com> wrote:
> our input is a line of text which may be parsed to e.g. A or B object.
> We want all A objects written to "A.avro" files, while all B objects written
> to "B.avro".
>
> I looked into AvroMultipleOutputs class:
> http://avro.apache.org/docs/1.7.4/api/java/org/apache/avro/mapreduce/AvroMultipleOutputs.html
> There is an example, however, it's not quite clear.
> For job submission, it uses AvroMultipleOutputs.addNamedOutput to add
> schemas for A and B.
> In my program looks like:
> AvroMultipleOutputs.addNamedOutput(job, "A",
> AvroKeyOutputFormat.class, aSchema, null);
> AvroMultipleOutputs.addNamedOutput(job, "B",
> AvroKeyOutputFormat.class, bSchema, null);
> I believe this is for Reducer output files.
>
> My question is what the Mapper output should be, in specific what
> "job.setMapOutputValueClass" should be,
> since the Mapper output could be A or B object, with schema aSchema or
> bSchema.
>
> In my progam, I simply set it to GenericData, but get error as below:
>
> 14/03/06 15:55:34 INFO mapreduce.Job: Task Id :
> attempt_1393817780522_0012_m_000010_2, Status : FAILED
> Error: java.lang.NullPointerException
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:989)
> at
> org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:390)
> at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:79)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:746)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
> at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:165)
> 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:1491)
> at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:160)
>
> I have no idea what this means.
--
Harsh J