Greenplum Database Configuration and Maintenance

You must configure Greenplum Database client host access and role privileges and attributes before using the Greenplum-Spark Connector to transfer data between your Greenplum Database and Spark clusters.

Once you start running Spark applications that use the Greenplum-Spark Connector, you may be required to perform certain Greenplum Database maintenance tasks.

These Greenplum Database configuration and maintenance tasks, described below, must be performed by a Greenplum user with administrative (SUPERUSER) privileges unless otherwise noted.

Configuring Greenplum Database

Client Host Access

You must explicitly configure Greenplum Database to permit access from all Spark nodes and stand-alone clients. Configure access for each Spark node, Greenplum database, and Greenplum Database role combination in the pg_hba.conf file on the master node.

Refer to Configuring Client Authentication in the Greenplum Database documentation for detailed information on configuring pg_hba.conf.

Role Privileges

The Greenplum-Spark Connector uses JDBC to communicate with the Greenplum Database master node. The Greenplum user/role name that you provide when you use the Greenplum-Spark Connector to transfer data between Greenplum Database and Spark must have certain privileges assigned by the administrator:

  • The user/role must have USAGE and CREATE privileges on each non-public database schema in which a table to be transferred resides:

    <db-name>=# GRANT USAGE, CREATE ON SCHEMA <schema_name> TO <user_name>;
    
  • The user/role must have the SELECT privilege on every Greenplum Database table that the user will read into Spark:

    <db-name>=# GRANT SELECT ON <schema_name>.<table_name> TO <user_name>;
    
  • The user/role must have permission to create writable external tables using the Greenplum Database gpfdist protocol:

    <db-name>=# ALTER USER <user_name> CREATEEXTTABLE(type = 'writable', protocol = 'gpfdist');
    

See the Greenplum Database Managing Roles and Privileges documention for further information on assigning privileges to Greenplum Database users.

Greenplum Database Maintenance Tasks

The Greenplum-Spark Connector uses Greenplum Database external tables to load Greenplum data into Spark. Maintenance tasks related to these external tables may include:

  • Periodically checking the status of your Greenplum Database catalogs for bloat, and VACUUM-ing the catalog as appropriate. Refer to the Greenplum Database System Catalog Maintenance and VACUUM documentation for further information.
  • Periodically ANALYZE-ing the Greenplum Database tables that applications using the Greenplum-Spark Connector load into Spark. Refer to the Greenplum Database Updating Statistics with ANALYZE and ANALYZE documentation for further information.
  • Manually removing Greenplum-Spark Connector-created external tables when your Spark cluster shuts down abnormally. Refer to Cleaning Up Orphaned Greenplum External Tables for details related to this procedure.

In addition to users with Greenplum Database SUPERUSER privileges, database or table owners many perform the maintenance tasks identified above.