After adding a partition to an external table in Hive, how can I update/drop it?
You can update a Hive partition by, for example:
ALTER TABLE logs PARTITION(year = 2012, month = 12, day = 18)
SET LOCATION 'hdfs://user/darcy/logs/2012/12/18';
This command does not move the old data, nor does it delete the old data. It simply sets the partition to the new location.
To drop a partition, you can do
ALTER TABLE logs DROP IF EXISTS PARTITION(year = 2012, month = 12, day = 18);
in addition, you can drop multiple partitions from one statement (Dropping multiple partitions in Impala/Hive).
Extract from above link:
hive> alter table t drop if exists partition (p=1),partition (p=2),partition(p=3);
Dropped the partition p=1
Dropped the partition p=2
Dropped the partition p=3
OK
EDIT 1:
Also, you can drop bulk using a condition sign (>,<,<>), for example:
Alter table t
drop partition (PART_COL>1);
Alter table table_name drop partition (partition_name);
You can either copy files into the folder where external partition is located or use
INSERT OVERWRITE TABLE tablename1 PARTITION (partcol1=val1, partcol2=val2...)...
statement.
You may also need to make database containing table active
use [dbname]
otherwise you may get error (even if you specify database i.e. dbname.table )
FAILED Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. Unable to alter partition. Unable to alter partitions because table or database does not exist.
Related
I have a query that I want to execute daily that's to be partitioned by the date it's executed. The results of this query should be appended to a the same table.
My idea was ideally having something similar to the CREATE TABLE IF NOT EXISTS command for adding data by a new partition every day to the existing table if the partition doesn't already exist, but I can't figure out how I'd be able to integrate this in my query.
My query:
CREATE TABLE IF NOT EXISTS db_name.table_name
WITH (
external_location = 's3://my-query-results-location/',
format = 'PARQUET',
parquet_compression = 'SNAPPY',
partitioned_by = ARRAY['date_executed'])
AS
SELECT
{columns_that_I_am_selecting_here_including_'date_executed'}
What this does is create a new table for the first day it's executed but nothing happens for subsequent days, I'm assuming because of the CREATE TABLE IF NOT EXISTS validating that the table already exists and not proceeding with the logic.
Is there a way to modify my query to create a table for the first day executed and append the results by a new partition for each subsequent day?
I'm quite sure ALTER TABLE table_name ADD [IF NOT EXISTS] PARTITION would not apply to my use case here as I'm running a CTAS query.
You can simply use INSERT INTO existing_table SELECT....
Presumably your table is already partitioned, so include that partition column in the SELECT and Amazon Athena will automatically put the data in the correct directory.
For example, you might include hte column like this: SELECT ... CURRENT_DATE as date_executed
See: INSERT INTO - Amazon Athena
I am not able to drop partition in hive table.
ALTER TABLE db.table drop if exists partition(dt="****-**-**/id=**********");
OK
Time taken: 0.564 seconds
But partitions are not getting deleted
Below is the what I get when I check partitions of my table:
hive> show partitions db.table;
OK
dt=****-**-**/id=**********
dt=****-**-**/id=**********
dt=****-**-**/id=**********
dt=****-**-**/id=**********
After running Alter table db.table drop if exists command it should actually delete the partition . But it is not happening so .
Can you please suggest me on this.
Thanks in advance.
Try this:
ALTER TABLE db.table drop if exists partition(dt='****-**-**', id='**********');
As #leftjoin also mentioned, you have to specify partitions with comma seperated.
ALTER TABLE page_view DROP if exists PARTITION (dt='****-**-**', id='**********');
Please note -
In Hive 0.7.0 or later, DROP returns an error if the partition doesn't
exist, unless IF EXISTS is specified or the configuration variable
hive.exec.drop.ignorenonexistent is set to true.
Due to this reason, your query didn't fail and returned OK response.
I have an external table, now I want to add partitions to it. I have 224 unique city id's and I want to just write alter table my_table add partition (cityid) location /path; but hive complains, saying that I don't provide anything for the city id value, it should be e.g. alter table my_table add partition (cityid=VALUE) location /path;, but I don't want to run alter table commands for every value of city id, how can I do it for all id's in one go?
This is what hive command line looks like:
hive> alter table pavel.browserdata add partition (cityid) location '/user/maria_dev/data/cityidPartition';
FAILED: ValidationFailureSemanticException table is not partitioned but partition spec exists: {cityid=null}
Partition on physical level is a location (separate location for each value, usually looks like key=value) with data files. If you already have partitions directory structure with files, all you need is to create partitions in Hive metastore, then you can point your table to the root directory using ALTER TABLE SET LOCATION, then use MSCK REPAIR TABLE command. The equivalent command on Amazon Elastic MapReduce (EMR)'s version of Hive is: ALTER TABLE table_name RECOVER PARTITIONS. This will add Hive partitions metadata. See manual here: RECOVER PARTITIONS
If you have only not-partitioned table with data in it's location, then adding partitions will not work because the data needs to be reloaded, you need to:
Create another partitioned table and use insert overwrite to load partition data using dynamic partition load:
set hive.exec.dynamic.partition=true;
set hive.exec.dynamic.partition.mode=nonstrict;
insert overwrite table2 partition(cityid)
select col1, ... colN,
cityid
from table1; --partitions columns should be last in the select
This is quite efficient way to reorganize your data.
After this you can delete source table and rename your target table.
I have an HIVE table with daily partitions day wise, something like below (which includes future date's partition as well)
20160901
20160902
........
........
........
20160931
20161001
20161002
I want to pass one date say for example yesterday's date 20160922 and want to drop all partitions dynamically which are >= 20160922 (though today is 20160923, but I want to drop from 20160922 date).
How can I can drop all these partitions dynamically.
You can not do in hive directly as it does not support dynamic sql.
There can be work around using shell script/or any script create file having drop partition script like below.
alter table partition_t drop if exists partition (y=20160922 );
alter table partition_t drop if exists partition (y=20160921 );
alter table partition_t drop if exists partition (y=20160920 );
...
then run hive -v -f ./file.sh
alter table partition_t drop if exists partition
Before Inserting Data Into Table Perform the below steps.
1) Go to Hdfs Folder of that table and delete all the folders Inside
Table Directory using Shell Commands. hadoop fs -rm r <>
2) Run MSCK repair Table to update the metadata about partitions.
above two steps will delete all the available partitions based on pattern.
Now Insert your new data.
You can drop partitions giving a range filter. For reference see that answer : https://stackoverflow.com/a/48422251/3132181
So your code could be like that:
Alter table mytable drop partition (datehour >= '20160922')
I use hive-0.10.0-cdh-4.7.0 in my environment.
I have a table named test store as sequence file and some partitions by date_dim like below:
game=Test/date_dim=2014-07-01
game=Test/date_dim=2014-07-11
game=Test/date_dim=2014-07-21
game=Test/date_dim=2014-07-31
I want to drop partitions between 2014-07-21 and 2014-07-30 in SQL command:
alter table test drop partition (date_dim>='2014-07-11',date_dim<='2014-07-30')
I hope these 2 partitions be deleted:
game=Test/date_dim=2014-07-11
game=Test/date_dim=2014-07-21
But actually, these 3 partitions be deleted:
game=Test/date_dim=2014-07-01
game=Test/date_dim=2014-07-11
game=Test/date_dim=2014-07-21
It seems hive drop partition only use the date_dim<='2014-07-30' condition.
Is there anyway to make hive drop partition as I wish?
You should convert the string to the date type, for that purpose you can use unix_timestamp function:
alter table test drop partition (unix_timestamp(date_dim,'yyyy-MM-dd')>=unix_timestamp('2014-07-11','yyyy-MM-dd'),unix_timestamp(date_dim,'yyyy-MM-dd')<=unix_timestamp('2014-07-30','yyyy-MM-dd'))