Greenplum Connector

The Greenplum connector allows querying and creating tables in an external Greenplum database. This can be used to join data between different systems like Greenplum and Hive, or between two different Greenplum instances. The Greenplum connector is extended from PostgreSQL connector, and We enable query push down feature for Greenplum connector.

Configuration

The base configuration of Greenplum connector is the same as PostgreSQL connector. For example, you can mount the Greenplum connector by creating a file named greenplum.properties in configuration directory etc/catalog. And create the file with the following contents, replacing the connection properties with correct string.

connector.name=greenplum
connection-url=jdbc:postgresql://example.net:5432/database
connection-user=root
connection-password=secret

Table modification

We can set the greenplum.allow-modify-table in the greenplum.properties to allow to modify the table or not. If greenplum.allow-modify-table is set to false, you can not create/rename/add column/rename column/drop column. And greenplum.allow-modify-table is set to true by default.

greenplum.allow-modify-table=true

Enable query push down in Greenplum connector

The query push down feature help you to push filter, project or other sql operators down to the Greenplum database which can reduce data transmission volume between openLooKeng and Greenplum data source. If jdbc.pushdown-enabled is set to false, query push down is disabled. Or jdbc.pushdown-enabled is set to true, query push down is enabled. The query push down feature is turn on by default. For example, to disable query push down, you can set connection properties in the catalog file as follows:

jdbc.pushdown-enabled=false
  • Mode for the push-down feature

By default, the push-down mode of the Greenplum connector is BASE_PUSHDOWN. If you want to enable all push-down, you can also set the parameter as follows:

jdbc.pushdown-module=FULL_PUSHDOWN  
#FULL_PUSHDOWN: All push down. BASE_PUSHDOWN: Partial push down, which indicates that filter, aggregation, limit, topN and project can be pushed down.

Others

About the other configurations and how to query greenplum, You can refer to the document of PostgreSQL connector for more details.