Enabling and Disabling GPORCA
Enabling and Disabling GPORCA
By default, Greenplum Database uses GPORCA instead of the Postgres Planner.
Server configuration parameters enable or disable GPORCA.
Although GPORCA is on by default, you can configure GPORCA usage at the system, database,
session, or query level using the optimizer parameter. Refer to one of the
following sections if you want to change the default behavior:
Note: You can disable the ability to enable or disable GPORCA with the
server configuration parameter optimizer_control. For information about the
server configuration parameters, see the Greenplum Database Reference
Guide.
Enabling GPORCA for a System
Set the server configuration parameter optimizer for the Greenplum Database system.
- Log into the Greenplum Database master host as gpadmin, the Greenplum Database administrator.
- Set the values of the server configuration parameters. These Greenplum Database
gpconfig utility commands sets the value of the parameters to
on:
$ gpconfig -c optimizer -v on --masteronly
- Restart Greenplum Database. This Greenplum Database
gpstop utility command reloads the postgresql.conf
files of the master and segments without shutting down Greenplum Database.
gpstop -u
Enabling GPORCA for a Database
Set the server configuration parameter optimizer for individual Greenplum databases with the ALTER DATABASE
command. For example, this command enables GPORCA for the database
test_db.
> ALTER DATABASE test_db SET OPTIMIZER = ON ;
Enabling GPORCA for a Session or a Query
You can use the SET command to set optimizer server
configuration parameter for a session. For example, after you use the
psql utility to connect to Greenplum Database, this
SET command enables GPORCA:
> set optimizer = on ;
To set the parameter for a specific query, include the SET command prior to running the query.