In hindsight, I have learned to create external tables so if I get into a
situation like this, I don't have to look up the appropriate alter table
statment (if it exists at all), I can just drop the external table and
re-create it:-)
Mark
----- Original Message -----
From: "Sai Naga" <freshair1...@gmail.com>
To: user@hive.apache.org
Sent: Tuesday, June 19, 2012 6:16:31 PM
Subject: Re: create external table on existing hive partitioned table ?
Thanks Mark,
The reason to create the 2nd table is One of the column is defined as string in
the first table, I wanted to read the string into Map data type.
i.e
Existing table.
{"UY": 2, "BR": 1}
{"LV": 1, "BR": 1}
To
Country Map<Sting, int >
Thanks
Gopi
On Tue, Jun 19, 2012 at 1:37 PM, Mark Grover < mgro...@oanda.com > wrote:
Sai,
Maybe I don't understand your question properly but creating an external table
on a partitioned table is no different than create an external table on a
non-partitioned one.
Your syntax looks right. After table creation, you would have to add all
existing partitions of the table so that the new table's metadata is properly
populated.
You can do that using a command like "ALTER TABLE page_access_m RECOVER
PARTITIONS" on Amazon EMR Hive or using msck on Apache Hive (more details at:
https://issues.apache.org/jira/browse/HIVE-874 )
Does that answer your question?
On a related note, having two tables over the same data could be troublesome.
For example, if one query adds a partition to one table, you would have to
remember to recover partitions on the on the other table before you access your
data through it. If the schema for both the tables is the same (except the fact
that one is managed while other is external), any particular reason you'd like
to create a new table?
Mark
----- Original Message -----
From: "Sai Naga" < freshair1...@gmail.com >
To: user@hive.apache.org
Sent: Tuesday, June 19, 2012 4:19:25 PM
Subject: create external table on existing hive partitioned table ?
Is it possible, to create external table on a existing hive table which is
partitioned.
I have a existing hive table which is partitioned by dt and group like below
desc page_access;
page string
country string
dt string ( Partitioned column )
group string ( Partitioned column )
dfs -tail file /user/hive/warehouse/page_access/dt=2012-06-01/group=a/000003_0
PXXXXX1 {"UY": 2, "BR": 1}
PXXXXX2 {"LV": 1, "BR": 1}
Is it possible to define a external table something like..
create external table page_access_m
(
page string
country map(<string>,<int>)
)PARTITIONED BY(dt STRING, group STRING)
location /user/hive/warehouse/page_access;
currently I'm using hive.0.6
Thanks
Sai
