SKIP_PROJS

Specifies which projections to avoid using for a queried table. If SKIP_PROJS excludes all available projections that are valid for the query, the optimizer issues a warning and ignores the projection hints.

Syntax

FROM table-name /*+SKIP_PROJS( [[database.]schema.]projection[,...] )*/

Arguments

[database.]schema

Database and schema. The default schema is public. If you specify a database, it must be the current database.

projection

A projection to skip. You can specify a list of comma-delimited projections.

Examples

In this example, the EXPLAIN output shows that the optimizer uses the projection public.employee_dimension_b0 for a given query:

QUERY PLAN DESCRIPTION:
------------------------------

 EXPLAIN SELECT employee_last_name, employee_first_name, employee_city, job_title FROM employee_dimension;

 Access Path:
 +-STORAGE ACCESS for employee_dimension [Cost: 59, Rows: 10K (NO STATISTICS)] (PATH ID: 1)
 |  Projection: public.employee_dimension_b0
 |  Materialize: employee_dimension.employee_first_name, employee_dimension.employee_last_name, employee_dimension.employee_city, employee_dimension.job_title
 |  Execute on: All Nodes

You can use the SKIP_PROJS hint to avoid using this projection. If another projection is available that is valid for this query, the optimizer uses it instead:

QUERY PLAN DESCRIPTION:
------------------------------

EXPLAIN SELECT employee_last_name, employee_first_name, employee_city, job_title FROM employee_dimension /*+SKIP_PROJS('public.employee_dimension')*/;

 Access Path:
 +-STORAGE ACCESS for employee_dimension [Cost: 156, Rows: 10K (NO STATISTICS)] (PATH ID: 1)
 |  Projection: public.employee_dimension_super
 |  Materialize: employee_dimension.employee_first_name, employee_dimension.employee_last_name, employee_dimension.emplo
yee_city, employee_dimension.job_title
 |  Execute on: Query Initiator