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SAS/ACCESS 9.2 for Relational Databases: Reference, Fourth Edition

SAS/ACCESS 9.2 for Relational Databases: Reference, Fourth Edition

SAS/ACCESS 9.2 for Relational Databases: Reference, Fourth Edition

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544 Passing Joins to Greenplum 4 Chapter 17Passing Joins to GreenplumFor a multiple libref join to pass to Greenplum, all of these components of theLIBNAME statements must match exactly.3 user ID (USER=)3 password (PASSWORD=)3 host(HOST=)3 server (SERVER=)3 database (DATABASE=)3 port (PORT=)3 data source (DSN=, if specified)3 SQL functions (SQL_FUNCTIONS=)For more in<strong>for</strong>mation about when and how <strong>SAS</strong>/<strong>ACCESS</strong> passes joins to the DBMS,see “Passing Joins to the DBMS” on page 43.Bulk Loading <strong>for</strong> GreenplumOverviewBulk loading provides high-per<strong>for</strong>mance access to external data sources. MultipleGreenplum instances read data in parallel, which enhances per<strong>for</strong>mance.Bulk loading enables you to insert large data sets into Greenplum tables in theshortest span of time. You can also use bulk loading to execute high-per<strong>for</strong>mance SQLqueries against external data sources, without first loading those data sources into aGreenplum database. These fast SQL queries enable you to optimize the extraction,trans<strong>for</strong>mation, and loading tasks that are common in data warehousing.Two types of external data sources, external tables and Web tables, have differentaccess methods. External tables contain static data that can be scanned multiple times.The data does not change during queries. Web tables provide access to dynamic datasources as if those sources were regular database tables. Web tables cannot be scannedmultiple times. The data can change during the course of a query.The following sections show you how to access external tables and Web tables usingthe bulk-loading facility.Using Protocols to Access External TablesUse these protocols to access (static) external tables.gpfdist://To use the gpfdist:// protocol, install and configure the gpfdist (Greenplum filedistribution) program on the host that stores the external tables see “Configuringthe File Server” on page 545. The gpfdist utility serves external tables in parallelto the primary Greenplum database segments. The gpfdist:// protocol isadvantageous because it ensures that all Greenplum database segments are usedduring the loading of external tables.

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