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Hive >> mail # user >> reg : reteriveing a single column from hive serde table


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Mohit Chaudhary01 2012-12-17, 08:21
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Nitin Pawar 2012-12-17, 08:24
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Mohit Chaudhary01 2012-12-17, 10:19
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Re: reg : reteriveing a single column from hive serde table
Mohit,
There is nothing wrong with the query. It seems (from the line below)
that you are using a custom SerDe:
org.apache.hadoop.hive.contrib.serde2.XmlInputFormat$XmlRecordReader.<init>(XmlInputFormat.java:76)

That seems to the causing the problem. You'd need to look into the
input format's code to see what's going on.

Mark

On Mon, Dec 17, 2012 at 2:19 AM, Mohit Chaudhary01
<[EMAIL PROTECTED]> wrote:
>
> I am using serde in hive to store data into hive table from xml file.
>
> Whenever I retrieve data using command select * from table it give all records  from table.
>
>
>
> But when I want to extract an individual column it gives error .
>
> Please Tell me how can I retrieve a single column from this table.
>
>
>
> This is the error when I try to extract a single column from hive serde table .
>
>
>
> java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
>
>         at org.apache.hadoop.hive.shims.Hadoop20SShims$CombineFileRecordReader.initNextRecordReader(Hadoop20SShims.java:306)
>
>         at org.apache.hadoop.hive.shims.Hadoop20SShims$CombineFileRecordReader.<init>(Hadoop20SShims.java:269)
>
>         at org.apache.hadoop.hive.shims.Hadoop20SShims$CombineFileInputFormatShim.getRecordReader(Hadoop20SShims.java:366)
>
>         at org.apache.hadoop.hive.ql.io.CombineHiveInputFormat.getRecordReader(CombineHiveInputFormat.java:413)
>
>         at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:371)
>
>         at org.apache.hadoop.mapred.MapTask.run(MapTask.java:325)
>
>         at org.apache.hadoop.mapred.Child$4.run(Child.java:270)
>
>         at java.security.AccessController.doPrivileged(Native Method)
>
>         at javax.security.auth.Subject.doAs(Subject.java:396)
>
>         at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1127)
>
>         at org.apache.hadoop.mapred.Child.main(Child.java:264)
>
> Caused by: java.lang.reflect.InvocationTargetException
>
>         at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
>
>         at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
>
>         at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
>
>         at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
>
>         at org.apache.hadoop.hive.shims.Hadoop20SShims$CombineFileRecordReader.initNextRecordReader(Hadoop20SShims.java:292)
>
>         ... 10 more
>
> Caused by: java.lang.NullPointerException
>
>         at org.apache.hadoop.hive.contrib.serde2.XmlInputFormat$XmlRecordReader.<init>(XmlInputFormat.java:76)
>
>         at org.apache.hadoop.hive.contrib.serde2.XmlInputFormat.getRecordReader(XmlInputFormat.java:44)
>
>         at org.apache.hadoop.hive.ql.io.CombineHiveRecordReader.<init>(CombineHiveRecordReader.java:68)
>
>         ... 15 more
>
>
>
>
>
> From: Nitin Pawar [mailto:[EMAIL PROTECTED]]
> Sent: Monday, December 17, 2012 1:54 PM
> To: [EMAIL PROTECTED]
> Subject: Re: reg : reteriveing a single column from hive serde table
>
>
>
> select * will just hdfs cat your file
>
>
>
> when you are using serde, do you have column separator in place? if not can you do select * from table limit 1
>
>
>
> to get normally a single coulmn you should do select column from table where column=value
>
>
>
> On Mon, Dec 17, 2012 at 1:51 PM, Mohit Chaudhary01 <[EMAIL PROTECTED]> wrote:
>
> Hi
>
> I am using serde in hive to store data into hive table from xml file.
>
> Whenever I retrieve data using command select * from table it give all records  from table.
>
>
>
> But when I want to extract an individual column it gives error .
>
> Please Tell me how can I retrieve a single column from this table.
>
>
>
> Thanks
>
> Mohit chaudhary
>
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