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From w00t w00t <w00...@yahoo.de>
Subject Re: Hive and Lzo Compression
Date Tue, 13 Aug 2013 07:13:11 GMT
Thanks for your replies and the link.

I could get it working, but wondered why the CREATE TABLE statement worked without the STORED
AS Clause as well...that's what puzzles me a bit...

But I will use the STORED AS Clause to be on the safe side.





________________________________
 Von: Lefty Leverenz <leftyleverenz@gmail.com>
An: user@hive.apache.org 
CC: w00t w00t <w00tel@yahoo.de> 
Gesendet: 19:06 Samstag, 10.August 2013
Betreff: Re: Hive and Lzo Compression
 


I'm not seeing any documentation link in Sanjay's message, so here it is again (in the Hive
wiki's language manual):  https://cwiki.apache.org/confluence/display/Hive/LanguageManual+LZO.



On Thu, Aug 8, 2013 at 3:30 PM, Sanjay Subramanian <Sanjay.Subramanian@wizecommerce.com>
wrote:

Please refer this documentation here
>Let me know if u need more clarifications so that we can make this document better and
complete
>
>
>Thanks
>
>
>sanjay
>
>From: w00t w00t <w00tel@yahoo.de>
>Reply-To: "user@hive.apache.org" <user@hive.apache.org>, w00t w00t <w00tel@yahoo.de>
>Date: Thursday, August 8, 2013 2:02 AM
>To: "user@hive.apache.org" <user@hive.apache.org>
>Subject: Hive and Lzo Compression
>
>
>
>
>
>Hello,
> 
>I am started to run Hive with Lzo compression on Hortonworks 1.2
> 
>I have managed to install/configure Lzo and  hive -e "set io.compression.codecs" shows
me the Lzo Codecs:
>io.compression.codecs=
>org.apache.hadoop.io.compress.GzipCodec,
>org.apache.hadoop.io.compress.DefaultCodec,
>com.hadoop.compression.lzo.LzoCodec,
>com.hadoop.compression.lzo.LzopCodec,
>org.apache.hadoop.io.compress.BZip2Codec
> 
>However, I have some questions where I would be happy if you could help me.
>(1) CREATE TABLE statement
>
>
>I read in different postings, that in the CREATE TABLE statement, I have to use the following
STORAGE clause:
> 
>CREATE EXTERNAL TABLE txt_table_lzo (
>   txt_line STRING
>)
>ROW FORMAT DELIMITED FIELDS TERMINATED BY '||||'
>STORED AS INPUTFORMAT 'com.hadoop.mapred.DeprecatedLzoTextInputFormat' OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
>LOCATION '/user/myuser/data/in/lzo_compressed';
> 
>It works withouth any problems now to execute SELECT statements on this table with Lzo
data.
> 
>However I also created a table on the same data without this STORAGE clause:
> 
>CREATE EXTERNAL TABLE txt_table_lzo_tst (
>   txt_line STRING
>)
>ROW FORMAT DELIMITED FIELDS TERMINATED BY '||||'
>LOCATION '/user/myuser/data/in/lzo_compressed';
> 
>The interesting thing is, it works as well, when I execute a SELECT statement and this
table.
> 
>Can you help, why the second CREATE TABLE statement works as well?
>What should I use in DDLs? 
>Is it best practice to use the STORED AS clause with a "deprecatedLzoTextInputFormat"?
Or should I remove it?
> 
> (2) Output and Intermediate Compression Settings 
> 
>I want to use output compression .
> 
>In "Programming Hive" from Capriolo, Wampler, Rutherglen the following commands are recommended:
>SET hive.exec.compress.output=true;
>SET mapred.output.compression.codec=com.hadoop.compression.lzo.LzopCodec;
> 
>          However, in some other places in forums, I found the following recommended
settings:
>SET hive.exec.compress.output=true
>SET mapreduce.output.fileoutputformat.compress=true
>SET mapreduce.output.fileoutputformat.compress.codec=com.hadoop.compression.lzo.LzopCodec
> 
>Am I right, that the first settings are for Hadoop versions prior 0.23?
>Or is there any other reason why the settings are different?
> 
>I am using Hadoop 1.1.2 with Hive 0.10.0.
>Which settings would you recommend to use?
> 
>--------------
>          I also want to compress intermediate results.
>         
>         Again, in  "Programming Hive" the following settings are recommended:
>         SET hive.exec.compress.intermediate=true;
>         SET mapred.map.output.compression.codec=com.hadoop.compression.lzo.LzopCodec;
> 
>          Is this the right setting?
>
>          Or should I again use the settings (which look more valid for Hadoop
0.23 and greater)?:
>          SET hive.exec.compress.intermediate=true;
>          SET mapreduce.map.output.compression.codec=com.hadoop.compression.lzo.LzopCodec;
> 
>Thanks
> 
>
>
>
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-- Lefty 
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