I have my data in data/2011/01/13/0100/file in HDFS, each of thes file contain data in tab separated, say name, ip , url.
I want to create a table in Hive and import the data from hdfs, table should contain time,name, ip and url.
How can I import these using Hive ? r the data should be in some other format so that I can import the time as well ?
You need to create the table to load the files into and then use the LOAD DATA command to load the files into the Hive tables. See the Hive documentation for the precise syntax to use.
Regards,
Jeff
To do this you have to use partitions, read more about them here:
http://wiki.apache.org/hadoop/Hive/LanguageManual/DDL#Add_Partitions
partition column in hive
You can create an external table for such data.
Something like:
CREATE EXTERNAL TABLE log_data (name STRING, ip STRING, url STRING)
PARTITIONED BY (year BIGINT, month BIGINT, day BIGINT, hour BIGINT)
row format delimited fields terminated by '\t' stored as TEXTFILE
location 'data'
Related
On using PARTITIONED BY or CLUSTERED BY keywords while creating Hive tables,
hive would create separate files corresponding to each partition or bucket. But for external tables is this still valid. As my understanding is data files corresponding to external files are not managed by hive. So does hive create additional files corresponding to each partition or bucket and move corresponding data in to these files.
Edit - Adding details.
Few extracts from "Hadoop: Definitive Guide" - "Chapter 17: Hive"
CREATE TABLE logs (ts BIGINT, line STRING) PARTITIONED BY (dt STRING, country STRING);
When we load data into a partitioned table, the partition values are specified explicitly:
LOAD DATA LOCAL INPATH 'input/hive/partitions/file1' INTO TABLE logs PARTITION (dt='2001-01-01', country='GB');
At the filesystem level, partitions are simply nested sub directories of the table directory.
After loading a few more files into the logs table, the directory structure might look like this:
The above table was obviously a managed table, so hive had the ownership of data and created a directory structure for each partition as in the above tree structure.
In case of external table
CREATE EXTERNAL TABLE logs (ts BIGINT, line STRING) PARTITIONED BY (dt STRING, country STRING);
Followed by same set of load operations -
LOAD DATA LOCAL INPATH 'input/hive/partitions/file1' INTO TABLE logs PARTITION (dt='2001-01-01', country='GB');
How will hive handle these partitions. As for external tables with out partition, hive will simply point to the data file and fetch any query result by parsing the data file. But in case of loading data in to a partitioned external table, where are the partitions created.
Hope fully in hive warehouse? Can someone support or clarify this?
Suppose partitioning on date as this is a common thing to do.
CREATE EXTERNAL TABLE mydatabase.mytable (
var1 double
, var2 INT
, date String
)
PARTITIONED BY (date String)
LOCATION '/user/location/wanted/';
Then add all your partitions;
ALTER TABLE mytable ADD PARTITION( date = '2017-07-27' );
ALTER TABLE mytable ADD PARTITION( date = '2017-07-28' );
So on and so forth.
Finally you can add your data in the proper location. You will have an external partitioned file.
There is an easy way to do this.
Create your External Hive table first.
CREATE EXTERNAL TABLE database.table (
id integer,
name string
)
PARTITIONED BY (country String)
LOCATION 'xxxx';
Next you have to run a MSCK command (metastore consistency check)
msck repair table database.table
This command will recover all partitions that are available in your path and update the metastore. Now, if you run your query against your table, data from all partitions will be retrieved.
I have a hive table schema stored in one hdfs file schema.avsc.
I want to create a hive table of the same schema and want to dump a data from another hdfs path where data is stored in HDFS file system.
1 : How can i create a table ?
2 : How can i dump a data stored in hdfs file into created table ?
How can i create a table ?
The Apache Hive documentation on the AvroSerDe shows the syntax for creating a table based on an Avro schema stored in a file. For convenience, I'll repeat one of the examples here:
CREATE TABLE kst
PARTITIONED BY (ds string)
ROW FORMAT SERDE
'org.apache.hadoop.hive.serde2.avro.AvroSerDe'
STORED AS INPUTFORMAT
'org.apache.hadoop.hive.ql.io.avro.AvroContainerInputFormat'
OUTPUTFORMAT
'org.apache.hadoop.hive.ql.io.avro.AvroContainerOutputFormat'
TBLPROPERTIES (
'avro.schema.url'='http://schema_provider/kst.avsc');
This example pulls the schema file from a web server. The documentation also shows other options, such as pulling from a local file, depending on your specific needs.
I recommend reading the entire AvroSerDe documentation page. There is a lot of useful information there about getting the most out of using Hive with Avro.
How can i dump a data stored in hdfs file into created table ?
You can define an external table that references the existing HDFS files. The documentation page for External Tables shows the syntax. Repeating an example:
CREATE EXTERNAL TABLE page_view(viewTime INT, userid BIGINT,
page_url STRING, referrer_url STRING,
ip STRING COMMENT 'IP Address of the User',
country STRING COMMENT 'country of origination')
COMMENT 'This is the staging page view table'
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\054'
STORED AS TEXTFILE
LOCATION '<hdfs_location>';
After defining the external table, you can then use an INSERT-SELECT query that reads from the external table and writes to the Avro table. The documentation on Inserting data into Hive Tables from queries describes the INSERT-SELECT syntax. For example:
FROM page_view_stg pvs
INSERT OVERWRITE TABLE page_view PARTITION(dt='2008-06-08', country)
SELECT pvs.viewTime, pvs.userid, pvs.page_url, pvs.referrer_url, null, null, pvs.ip, pvs.cnt
I have an hive external table in the HDFS and i am trying to create a hive managed table above it.i am using textfile format with snappy compression but i want to know how it helps the table.
CREATE TABLE standard_cd
(
last_update_dttm TIMESTAMP,
last_operation_type CHAR (1) ,
source_commit_dttm TIMESTAMP,
transaction_dttm TIMESTAMP ,
transaction_type CHAR (1)
)
PARTITIONED BY (process_dt DATE)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '|'
STORED AS TEXTFILE
TBLPROPERTIES ("orc.compress" = "SNAPPY");
Let me know if any issues in creating in this format.
As such their is no issue while creating.
but difference in properties:
Table created and stored as TEXTFILE:
Table created and stored as ORC:
although the size of both tables were same after loading some data.
also check documentation about ORC file format
I am running Hive and Hue on Cloudera.
I have the following text file uploaded to hdfs. And I'm trying to create an external table in hive partitioned by id. For whatever reason, it's not working.
/user/test2/test.csv
id,name,age
1,sam,10
2,john,5
1,rick,4
Hive:
CREATE EXTERNAL TABLE IF NOT EXISTS testDB (
name STRING,
age INT
)
COMMENT 'This is the test database'
PARTITIONED BY (id INT)
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
LOCATION '/user/test2/'
TBLPROPERTIES ("skip.header.line.count" = "1");
On Hue, hive editor, when I tried to look at sample data, it says list index out of range. Not sure what this is. The external table will work correctly if I remove the partitioned by.
Your data located on '/user/test2/test.csv' is structured on three columns, but your schema defined for the table 'testDB' contains two columns, it is normal that you have this error.
You have to update your script, by adding the id column:
CREATE EXTERNAL TABLE IF NOT EXISTS testDB (
id INT,
name STRING,
age INT
)
...
you do not have the data partitioned because you have not created it. You should follow 3 steps:
1- Mount the data pointing to the .csv file.
CREATE EXTERNAL TABLE TableName (id int, name string, age int)
ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n'
STORED AS TEXTFILE LOCATION '/user/test2/';
Create the partitioned data
CREATE EXTERNAL TABLE IF NOT EXISTS testDB (
name STRING,
age INT )
COMMENT 'This is the test database'
PARTITIONED BY (id INT)
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
LOCATION '/user/other/location'
TBLPROPERTIES ("skip.header.line.count" = "1");
Insert the data from your previous table to the final table.
insert into table testDB
partition (archive) select name, age from
TableName;
Hope this help you.
So I finally solved my problem. Below is my solution.
I am using Cloudera vm - 5.4.2, when I started Hue, the Hive setting in Hue is pointing to HiveServer2; But I created the tables using Hive CLI. So basically the table only exists in HiveServer1.
Solution:
Instead of using Hive CLI, create table in beeline, everything in Hue should work then.
I have a partitioned Hive table that i want to load in a Pig script and would like to add partition as column also.
How can I do that?
Table definition in Hive:
CREATE EXTERNAL TABLE IF NOT EXISTS transactions
(
column1 string,
column2 string
)
PARTITIONED BY (datestamp string) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t'
LOCATION '/path';
Pig script:
%default INPUT_PATH '/path'
A = LOAD '$INPUT_PATH'
USING PigStorage('|')
AS (
column1:chararray,
column2:chararray,
datestamp:chararray
);
The datestamp column is not populated. Why is it so?
I am sorry I didn't get the part which says add partition as column also. Once created, partition keys behave like regular columns. What exactly do you need?
And you are loading the data directly from a given HDFS location, not as a Hive table. If you intend to use Pig to load/store data from/into a Hive table you should use HCatalog.
For example :
A = LOAD 'transactions' USING org.apache.hcatalog.pig.HCatLoader();