Github user eminency commented on a diff in the pull request:
https://github.com/apache/tajo/pull/677#discussion_r37380089
--- Diff: tajo-docs/src/main/sphinx/partitioning/alter_partition.rst ---
@@ -0,0 +1,66 @@
+********************************
+Alter partition
+********************************
+
+You can ALTER TABLE to add or drop partitions for partition table.
+
+For example, assume there is a ``student`` table composed of the following
schema.
+
+.. code-block:: sql
+
+ CREATE TABLE student (
+ id INT,
+ name TEXT,
+ grade TEXT
+ ) PARTITION BY COLUMN (country TEXT, city TEXT);
+
+
+========================
+ADD PARTITION
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> [IF NOT EXISTS] ADD PARTITION (<partition
column> = <partition value>, ...) [LOCATION = <partition's path>]
+
+*Description*
+
+You can use ``ALTER TABLE ADD PARTITION`` to ADD PARTITIONs to a table.
The location must be a directory inside of which data files reside. If the
location doesn't exist on the file system, Tajo will make the location by
force. ``ADD PARTITION`` changes the table metadata, but does not load data. If
the data does not exist in the partition's location, queries will not return
any results. An error is thrown if the partition for the table already exists.
You can use ``IF NOT EXISTS`` to skip the error.
+
+*Examples*
+
+.. code-block:: sql
+
+ -- Each ADD PARTITION clause creates a subdirectory in HDFS.
+ ALTER TABLE student ADD PARTITION (country='KOREA', city='SEOUL');
+ ALTER TABLE student ADD PARTITION (country='KOREA', city='PUSAN');
+ ALTER TABLE student ADD PARTITION (country='USA', city='NEWYORK');
+ ALTER TABLE student ADD PARTITION (country='USA', city='BOSTON');
+ -- Redirect queries, INSERT, and LOAD DATA for one partition to a
specific different directory.
+ ALTER TABLE student ADD PARTITION (country='USA', city='BOSTON')
LOCATION '/usr/external_data/new_years_day';
+
+
+========================
+ DROP PARTITION
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> [IF EXISTS] DROP PARTITION (<partition column>
= <partition value>, ...) [PURGE]
+
+*Description*
+
+You can use ``ALTER TABLE DROP PARTITION`` to drop a partition for a
table. This doesn't remove the data for partition table. But if ``PURGE`` is
specified, the partition data will be removed. The metadata is completely lost
in all cases. An error is thrown if the partition for the table doesn't exists.
You can use ``IF EXISTS`` to skip the error.
+
+*Examples*
+
+.. code-block:: sql
+
+ -- Delete just metadata
+ ALTER TABLE table1 DROP PARTITION (country = 'KOREA' , city = 'SEOUL');
+ -- Delete table data and metadata
+ ALTER TABLE table1 DROP PARTITION (country = 'USA', city = 'NEWYORK' )
PURGE
--- End diff --
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