Accessing SPD Server Using SAS

SPD Server can use SQL pass-through commands. The SPD Server host can perform complete SQL expression evaluation. SPD Server also supports nested SQL pass-through commands. Nested SQL pass-through commands allow you to connect to other SPD Server hosts while you are connected to your SPD Server host. You can use nested pass-through commands to distribute simultaneous SQL queries across multiple SPD Server hosts on your network.

The SQL pass-through facility can be accessed with or without SAS syntax and applications.You can use SAS to connect to an SPD Server host by using pass-through syntax from PROC SQL or from other SQL-aware SAS applications. Accessing and Creating SAS Scalable Performance Data (SPD) Server Tables has more detailed information about the SPD Server pass-through facility and provides examples of the syntax.

SAS users can initiate a client session by issuing a LIBNAME statement using the SASSPDS engine. LIBNAME access is shown in Figure 1.3. Connecting to SAS Scalable Performance Data (SPD) Server explains the mechanics of LIBNAME access to the engine and SPD Server LIBNAME options.

Distributed computing can enrich user resources, but it has an inherent problem. To connect to an SPD Server, you must know its location within your network. Instead of requiring users to memorize long paths or IP addresses, SPD Server software uses a specialized server called a Name Server. The SPD Server Name Server locates active SPD Server hosts on your network. A Name Server recognizes active SPD Server machines because all of the SPD Servers register with the Name Server as they start up and contact the host machine.

The Name Server keeps network addresses and a list of the LIBNAME domains for each SPD Server host. An SPD Server LIBNAME domain is a logical entity that SPD Server creates. A LIBNAME domain maintains domain attributes such as the library name, owner, and contents. Whenever you use a LIBNAME statement to specify a LIBNAME domain, a Name Server can determine the correct directory path to the SPD Server data library and connect your SPD Server client to the SPD Server host for that domain.

SPD Server clients use port addressing to locate a SPD Server Name Server. SPD Server administrators must assign a port address to a Name Server. Most UNIX system clients use their local /etc/services file to register port assignments. The service name for an SPD Server Name Server in an /etc/services file must be SPDSNAME. PC clients use services files to register port assignments. The services files on PC clients vary bsed on the software that the PC network uses.

When a client SPD Server application issues a LIBNAME statement that does not include the port address of the Name Server, SPD Server checks the services file for the SPDSNAME entry and the port address. Registering the Name Server port assignment in your client's network services file relieves you from the responsibility of coding Name Server port numbers when you write SAS jobs. For examples of using a LIBNAME statement to connect, see LIBNAME Example Statements .