Help Center/ GaussDB/ Feature Guide(Distributed_8.x)/ Partitioned Table/ Introduction to Partitioned Tables/ Basic Concepts/ Partitioned Table
Updated on 2024-06-07 GMT+08:00
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Partitioned Table

A table that is displayed to users. Users can add, delete, query, and modify data in the table using common DML statements. Generally, it is defined by explicitly running the PARTITION BY statement when DDL statements are used for creating a table. After the table is created, an entry is added to the pg_class table, and the content in the parttype column is 'p', indicating that the entry is a partitioned table. The partitioned table is usually a logical form, and does not store any data.

Example: t1_hash is a partitioned table whose partitioning type is hash. 
gaussdb=# CREATE TABLE t1_hash (c1 INT, c2 INT, c3 INT)
PARTITION BY HASH(c1)
(
    PARTITION p0,
    PARTITION p1,
    PARTITION p2,
    PARTITION p3,
    PARTITION p4,
    PARTITION p5,
    PARTITION p6,
    PARTITION p7,
    PARTITION p8,
    PARTITION p9
);

gaussdb=# \d+ t1_hash
                      Table "public.t1_hash"
Column |  Type    | Modifiers | Storage | Stats target | Description
--------+---------+-----------+---------+--------------+-------------
c1     | integer |              | plain   |                 |
c2     | integer |              | plain   |                 |
c3     | integer |              | plain   |                 |
Partition By HASH(c1)
Number of partitions: 10 (View pg_partition to check each partition range.)
Distribute By: HASH(c1)
Location Nodes: ALL DATANODES
Has OIDs: no
Options: orientation=row, compression=no

-- Query the partitioning type of table t1_hash.
gaussdb=#  SELECT relname, parttype FROM pg_class WHERE relname = 't1_hash';
relname | parttype
---------+----------
t1_hash | p           
(1 row)

-- Drop table t1_hash.
gaussdb=# DROP TABLE t1_hash;
Parent topic: Basic Concepts