-Re: Merging different HDFS file for HIVE
Sanjay Subramanian 2013-07-27, 01:23
We have a similar situation like this in production…for your case case I would propose the following steps
1. Design a map reduce job (Job Output format - Text, Lzo, Snappy, your choice)
Inputs to Mapper
-- records from these three feeds
Outputs from Mapper
-- Key = <EMP1> Value = <feed1~field1 field2 field6 field9>
-- Key = <EMP1> Value = <feed2~field5 field7 field10>
-- Key = <EMP1> Value = <feed3~field3 field4 field8>
-- Key = <EMP1> Value = <field1 field2 field3 field4 field5 field6 field7 field8 field9 field10>
2. (Optional) If u use LZO then u will need to run LzoIndexer
3. CREATE TABLE IF NOT EXISTS YOUR_HIVE_TABLE
4. ALTER TABLE ADD PARTITION (foo1 = , foo2 = ) LOCATION 'path/to/files'
From: Stephen Sprague <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Reply-To: "[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>" <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Date: Friday, July 26, 2013 4:37 PM
To: "[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>" <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
Subject: Re: Merging different HDFS file for HIVE
i like #2.
so you have three, say, external tables representing your three feed files. After the third and final file is loaded then join 'em all together - maybe make the table partitioned for one per day.
alter table final add partition (datekey=YYYYMMDD);
insert overwrite table final partition (datekey=YYYYMMDD) select EMP_ID,f1,...,f10 from FF1 a join FF2 b on (a.EMP_ID=b.EMP_ID join FF3 c on (b.EMP_ID=c.EMP_ID)
Or a variation on #3. make a view on the three tables which would look just like the select statement above.
What do you want to optimize for?
On Fri, Jul 26, 2013 at 5:30 AM, Nitin Pawar <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> wrote:
Option 1 ) Use pig or oozie, write a workflow and join the files to a single file
Option 2 ) Create a temp table for each of the different file and then join them to a single table and delete temp table
Option 3 ) don't do anything, change your queries to look at three different files when they query about different files
Wait for others to give better suggestions :)
On Fri, Jul 26, 2013 at 4:22 PM, Ramasubramanian Narayanan <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> wrote:
Please help in providing solution for the below problem... this scenario is applicable in Banking atleast...
I have a HIVE table with the below structure...
For the above table, I will get the values for each feed in different file. You can imagine that these files belongs to same branch and will get at any time interval. I have to load into table only if I get all 3 files for the same branch. (assume that we have a common field in all the files to join)
Feed file 1 :
Feed File2 :
Feed File3 :
Now the question is,
what is the best way to make all these files to make it as a single file so that it can be placed under the HIVE structure.
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