Sweet this makes perfect sense. We are actually already using an ooze job that
wait for input and does some pre-processing on the logs before finally
archiving in HDFS. It would make sense to just attach some job to import this
data and partition it by date at the same time.
Just one last question regarding external tables and tables that Hive manages.
Am I correct to assume that when you let hive manager your table it moves
everything where you want and it takes care of partitioning. But if I want to
manage the directory structure myself, or use an existing one like we have, I
will need to use the external keyword. Does that sound about right?
On Mar 29, 2013, at 12:45 PM, Sanjay Subramanian
<sanjay.subraman...@wizecommerce.com> wrote:
> I agree. BASH is super easy for things like this
>
> I have a daily alter partition script I call thru a java-action in Oozie
> (that Java class calls a HiveClient interface implementation)
> Example script that I run for us where date and server are partitions
> for r in $(hdfs dfs -ls /path/to/directory/in/hdfs |awk '{print $8}')
> do
> datestr=$(echo $r|cut -d "/" -f 10)
> serverstr=$(echo $r|cut -d "/" -f 11)
> $HIVE_HOME/bin/hive -hiveconf hive.root.logger=INFO,console -e "ALTER
> TABLE my_table ADD PARTITION (header_date='$datestr' ,
> header_servername='$serverstr') LOCATION '$r';"
> done
>
> From: Dean Wampler <dean.wamp...@thinkbiganalytics.com>
> Reply-To: "user@hive.apache.org" <user@hive.apache.org>
> Date: Friday, March 29, 2013 11:37 AM
> To: "user@hive.apache.org" <user@hive.apache.org>
> Subject: Re: Noob question on creating tables
>
> That's a drawback of external tables, but it's actually not as difficult as
> it sounds. It's easy to write a nightly "cron" job that creates the partition
> for the next day (or a job per month...), if someone on your team has some
> bash experience. Other job scheduling tools should support this too. Here's
> an example. First, a hive script that uses parameters for the date (Hive v0.8
> or newer):
>
> -- addlogpartition.hql
> ALTER TABLE log ADD IF NOT EXISTS PARTITION (year = ${YEAR}, month =
> ${MONTH}, day = ${DAY});
>
> Then, run this bash script AFTER MIDNIGHT:
>
> #!/bin/bash
> YEAR=$(date +%Y) # returns the string "2013" today.
> MONTH=$(date +%m) # returns the string "03" today, with the leading zero.
> DAY=$(date +%d) # returns the string "29" today. Will prefix with 0
> for dates < 10.
>
> # Assumes /path/to/2013/03/29 is the correct directory name:
> /path/to/hive -f /path/to/addlogpartition.hql -d YEAR=$YEAR -d MON=$MONTH -d
> DAY=$DAY
>
>
> (Of course, all the /path/to will be different...)
>
> So, be careful of how how "03" vs. "3" is handled in both the ALTER TABLE
> statement and the path. Off hand, I don't know if Hive will complain if you
> use 03 as an integer value in the ALTER TABLE statement.
>
>
> On Fri, Mar 29, 2013 at 1:16 PM, Mark <static.void....@gmail.com> wrote:
> Thanks
>
> Does this mean I need to create a partition for each day manually? There is
> no way to have infer that from my directory structure?
>
> On Mar 29, 2013, at 10:40 AM, Sanjay Subramanian
> <sanjay.subraman...@wizecommerce.com> wrote:
>
> > Hi
> >
> > CREATE EXTERNAL TABLE IF NOT EXISTS log_data(col1 datatype1, col2
> > datatype2, . . . colN datatypeN) PARTITIONED BY (YEAR INT, MONTH INT, DAY
> > INT) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t';
> >
> >
> > ALTER table log_data ADD PARTITION (YEAR=2013 , MONTH=2, DAY=27) LOCATION
> > '/path/to/YEAR/MONTH/DAY/directory/ON/HDFS';"
> >
> > Hive will read gzip and bz2 files out of the box.(so suppose you had
> > hourly log files in gzip format in your /YEAR/MONTH/DAY directory then it
> > will be read)
> > Snappy and LZO will need some jar installs and configs
> > https://github.com/toddlipcon/hadoop-lzo
> >
> > https://code.google.com/p/snappy/
> >
> >
> > Note that for example - gzip format is not splittable..so huge gzip files
> > without splits are not recommended as input to maps
> >
> > Hope this helps
> >
> > sanjay
> >
> >
> > On 3/29/13 10:19 AM, "Mark" <static.void....@gmail.com> wrote:
> >
> >> We have existing log data in directories in the format of YEAR/MONTH/DAY.
> >>
> >> - How can we create a table over this table without hive modifying and/or
> >> moving it?
> >> - How can we tell Hive to partition this data so it knows about each day
> >> of logs?
> >> - Does hive out of the box work with reading compressed files?
> >>
> >> Thanks
> >
> >
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>
>
>
> --
> Dean Wampler, Ph.D.
> thinkbiganalytics.com
> +1-312-339-1330
>
>
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> ======================
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