COPY_PARTITIONS_TO_TABLE

Copies partitions from one table to another. This lightweight partition copy increases performance by initially sharing the same storage between two tables. After the copy operation is complete, the tables are independent of each other. Users can perform operations on one table without impacting the other. These operations can increase the overall storage required for both tables.

Although they share storage space, Vertica considers the partitions as discrete objects for license capacity purposes. For example, copying a one TB partition would only consume one TB of space. Your Vertica license, however, considers them as separate objects consuming two TB of space.

Syntax

COPY_PARTITIONS_TO_TABLE (
    '[[database.]schema.]source‑table',
    'min‑range‑value',
    'max‑range‑value', 
    '[[database.]schema.]target‑table'
     [, 'force‑split']
)

Parameters

[database.]schema

Specifies a schema, by default public. If schema is any schema other than public, you must supply the schema name. For example:

myschema.thisDbObject

If you specify a database, it must be the current database.
source‑table The source table of the partitions to copy.
min‑range‑value
max‑range‑value 		The minimum and maximum value of partition keys to copy, where min‑range‑value must be ≤ max‑range‑value. To copy one partition, min‑range‑value and max‑range‑value must be equal.
target‑table

The target table of the partitions to copy. If the table does not exist, Vertica creates a table from the source table's definition, by calling CREATE TABLE with LIKE and INCLUDING PROJECTIONS clause. The new table inherits ownership from the source table. For details, see Replicating a Table..
force‑split

Optional Boolean argument, specifies whether to split ROS containers if the range of partition keys spans multiple containers or part of a single container:

  • true: Split ROS containers as needed.
  • false (default): Return with an error if ROS containers must be split to implement this operation.

Privileges

  • Ownership or USAGE privileges on the source table.
  • CREATE privileges on the target table, if COPY_PARTITIONS_TO_TABLE creates it.

Table Attribute Requirements

The following attributes of both tables must be identical:

  • Column definitions, including NULL/NOT NULL constraints
  • Segmentation
  • Partition clause
  • Number of projections
  • Projection sort order
  • Primary and unique key constraints. However, the key constraints do not have to be identically enabled. For more information on constraints, see Constraints in the Administrator's Guide.

    If the target table has primary or unique key constraints enabled and copying or moving the partitions will insert duplicate key values into the target table, Vertica rolls back the operation.

  • Check constraints. For MOVE_PARTITIONS_TO_TABLE and COPY_PARTITIONS_TO_TABLE, Vertica enforces enabled check constraints on the target table only. For SWAP_PARTITIONS_BETWEEN_TABLES, Vertica enforces enabled check constraints on both tables. If there is a violation of an enabled check constraint, Vertica rolls back the operation.
  • Number and definitions of text indices.

Table Restrictions

The following restrictions apply to the source and target tables:

  • If the source and target partitions are in different storage tiers, Vertica returns a warning but the operation proceeds. The partitions remain in their existing storage tier.
  • The following tables cannot be used as sources or targets:
    • Temporary tables
    • Virtual tables
    • System tables
    • External tables

Examples

If you call COPY_PARTITIONS_TO_TABLE and the target table does not exist, the function creates the table automatically. In the following example, the target table partn_backup.tradfes_200801 does not exist. COPY_PARTITIONS_TO_TABLE creates the table and replicates the partition. Vertica also copies all the constraints associated with the source table except foreign key constraints.

=> SELECT COPY_PARTITIONS_TO_TABLE (
          'prod_trades',
          '200801',
          '200801',
          'partn_backup.trades_200801');
COPY_PARTITIONS_TO_TABLE                          
-------------------------------------------------
 1 distinct partition values copied at epoch 15. 
(1 row)

See Also

Archiving Partitions