How to Update or Drop a Hive Partition?
- Update Hive Partition. You can use the Hive ALTER TABLE command to change the HDFS directory location of a specific...
- Rename Hive Partition. You can also use ALTER TABLE with PARTITION RENAME to rename the Hive partition. ... When you...
- Drop or Delete Hive Partition. Hive drop or delete partition is performed using ALTER TABLE...
How to drop multiple partitions in hive?
Drop multiple partitions in Hive 1 Components Involved 2 Sample Data. Here, 1 record belongs to 1 partition as we will store data partitioned by the year of joining. ... 3 Solution. If you already have a partitioned table, then skip this step else read this post for creating a table and loading data into it. 4 Wrapping Up. ...
How do I update a hive partition?
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.
How do I rename a hive partition?
Rename Hive Partition You can also use ALTER TABLE with PARTITION RENAME to rename the Hive partition. The below example rename partition state=’AL’ to state=’NY’ jdbc:hive2://127.0.0.1:10000 > ALTER TABLE zipcodes PARTITION (state ='AL') RENAME TO PARTITION (state ='NY');
How to remove external table Partition from hive metastore?
Note: Data moving to .Trash directory happens only for Internal/Managed table. For the external table, DROP partition just removes the partition from Hive Metastore and the partition is still present on HDFS. You need to run explicitly hadoop fs -rm commnad to remove the partition from HDFS.
How do I drop a partition?
Use the DROP_PARTITIONS function to drop one or more partition keys for a given table. You can specify a single partition key or a range of partition keys. If the WOS contains data for the target table, DROP_PARTITIONS first invokes a moveout operation.
Can we drop partition?
You cannot drop a partition from a reference-partitioned table. Instead, a drop operation on a parent table cascades to all descendant tables.
How do I drop a column from a partitioned table in Hive?
You cannot drop column directly from a table using command ALTER TABLE table_name drop col_name; The only way to drop column is using replace command.
How do I change the partition on a Hive table?
You have alter the partition column using simple swap method.Create a new temp table which is same schema as current table.Move all files in the old table to newly create table location. ... Alter the schema of the original table (Rename or drop the partitions)More items...
What happens when you drop a partition?
Dropping a partition will discard the rows stored in that partition as a DDL statement. This cannot be rolled back. It executes quickly and uses few system resources (Undo and Redo). You must be the owner of the table or have the DROP ANY TABLE privilege to drop a partition.
Does drop partition release space?
It is the ALTER TABLE TRUNCATE PARTITION, where you can either specify DROP STORAGE or REUSE STORAGE clause (in case of reuse, the space is not freed and can be used only by new rows inserted in the same partition). The DROP STORAGE should be the default option. But for partition drop, you do not have to worry.
How do I delete a partition on an external table?
This can be achieved as below.Alter external table as internal table -- by changing the TBL properties as external =false.Drop the partitions -- when you drop the partitions, data pertained to the partitions will also be dropped as now this table is managed table.Alter back the table as external=True.
How do I drop a column in a table?
Syntax. The syntax to drop a column in a table in MySQL (using the ALTER TABLE statement) is: ALTER TABLE table_name DROP COLUMN column_name; table_name.
How do I use alter command in Hive?
ALTER TABLE name RENAME TO new_name ALTER TABLE name ADD COLUMNS (col_spec[, col_spec ...]) ALTER TABLE name DROP [COLUMN] column_name ALTER TABLE name CHANGE column_name new_name new_type ALTER TABLE name REPLACE COLUMNS (col_spec[, col_spec ...])
How do you delete a table in Hive?
DROP TABLE command in the hive is used to drop a table inside the hive. Hive will remove all of its data and metadata from the hive meta-store. The hive DROP TABLE statement comes with a PURGE option.
What is Hive default partition?
Hive creates a default partition when the value of a partitioning column does not match the defined type of the column (for example, when a NULL value is used for any partitioning column). In Hive, any query that includes a filter on a partition column excludes any data that is stored in the table's default partition.
How does Hive partition work?
Hive organizes tables into partitions. It is a way of dividing a table into related parts based on the values of partitioned columns such as date, city, and department. Using partition, it is easy to query a portion of the data.