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)