Overview of GPORCA

GPORCA extends the planning and optimization capabilities of the Postgres Planner. GPORCA is extensible and achieves better optimization in multi-core architecture environments. Greenplum Database uses GPORCA by default to generate an execution plan for a query when possible.

GPORCA also enhances Greenplum Database query performance tuning in the following areas:

Queries against partitioned tables
Queries that contain a common table expression (CTE)
Queries that contain subqueries

In Greenplum Database, GPORCA co-exists with the Postgres Planner. By default, Greenplum Database uses GPORCA. If GPORCA cannot be used, then the Postgres Planner is used.

The following figure shows how GPORCA fits into the query planning architecture.

Note: All Postgres Planner server configuration parameters are ignored by GPORCA. However, if Greenplum Database falls back to the Postgres Planner, the planner server configuration parameters will impact the query plan generation. For a list of Postgres Planner server configuration parameters, see Query Tuning Parameters.