Vertica Analytics Platform Version 9.2.x Documentation

Unsegmented Clause

Specifies to distribute identical copies of table or projection data across the cluster. Use this clause to facilitate distributed query execution on tables and projections that are too small to benefit from segmentation.

Vertica uses the same name to identify all instances of an unsegmented projection. For more information about projection name conventions, see Projection Naming.

Syntax

UNSEGMENTED {NODE node | ALL NODES}

Parameters

NODE node Creates an unsegmented projection only on the specified node node. To obtain a list of all cluster nodes, query the system table V_CATALOG.NODES.
ALL NODES

Creates instances of the unsegmented projection on all cluster nodes. You must set this option if projection or system K-safety is greater than 0, otherwise Vertica regards the projection as unsafe and does not use it.

Example

This example creates an unsegmented projection for table store.store_dimension:

=> CREATE PROJECTION store.store_dimension_proj (storekey, name, city, state) 
             AS SELECT store_key, store_name, store_city, store_state 
             FROM store.store_dimension 
             UNSEGMENTED ALL NODES;
CREATE PROJECTION

=>  SELECT anchor_table_name anchor_table, projection_name, node_name 
      FROM PROJECTIONS WHERE projection_basename='store_dimension_proj';
  anchor_table   |   projection_name    |    node_name
-----------------+----------------------+------------------
 store_dimension | store_dimension_proj | v_vmart_node0001
 store_dimension | store_dimension_proj | v_vmart_node0002
 store_dimension | store_dimension_proj | v_vmart_node0003
(3 rows)