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Hive, mail # user - ALTER TABLE CHANGE COLUMN issue


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Re: ALTER TABLE CHANGE COLUMN issue
hardik doshi 2013-01-30, 19:12
Thanks, Nitin & Dean.

My hive table is backed by data files in hdfs and they do contain the additional field that I am adding in my hive table schema.

I noticed that if I remove partitions and recreate them after changing the column type, it works. But it does not work
on old partition for some weird reasons.

Any ideas?

-Hardik.
________________________________
 From: Dean Wampler <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Cc: hardik doshi <[EMAIL PROTECTED]>
Sent: Wednesday, January 30, 2013 5:51 AM
Subject: Re: ALTER TABLE CHANGE COLUMN issue
 

Right, the very important thing to remember about ALTER TABLE is that it only changes metadata about your table. It doesn't modify the data in any way. You have to do that yourself.
On Wed, Jan 30, 2013 at 2:17 AM, Nitin Pawar <[EMAIL PROTECTED]> wrote:

after u did alter table, did you add any new data to table with new schema? 
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>for the old data already present in data, if you add anything new in columns it will be null value 
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>On Wed, Jan 30, 2013 at 1:44 PM, hardik doshi <[EMAIL PROTECTED]> wrote:
>
>Hi,
>>
>>I am running into an issue where ALTER TABLE CHANGE COLUMN does not seem to be working.
>>
>>I have a table with a column data type looking like array<struct<a:int, b:int>> and I am trying to it change to array<struct<a:int, b:int, c:string>> based
>>on the underlying data schema change.
>>
>>
>>
>>The alter command succeeds and subsequent describe call shows me the updated table structure. But when tried querying the table,
>>it returns null for the newly added field.
>>
>>
>>This does not happen when a new table with updated column data type is created.
>>
>>
>>Is this a known bug?
>>
>>
>>Thanks,
>>Hardik.
>>
>>
>>PS:- My alter command: ALTER TABLE hardiktest CHANGE COLUMN col1 col2 array<struct<a:int, b:int, c:string>>.
>>
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>
>
>--
>Nitin Pawar
>
--
Dean Wampler, Ph.D.
thinkbiganalytics.com
+1-312-339-1330