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Teradata RDBMS Database Administration - NCR

NCR Teradata RDBMS Database Administration - NCR , 2004. - 616 p.
Download (direct link): teradatadatabaseadmin2004.pdf
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• PBSA—PCI Bus ESCON Adapter (ESCON fiber)

• EBCA—EISA Bus Channel Adapter (Bus and Tag)

• PBCA—PCI Bus Channel Adapter (Bus and Tag)

Depending on your workload and required throughput, you do not need to configure one HCA per node. In smaller systems (up to 4 or 6 nodes), you might configure 2 or 3 HCAs. In a two-node system, however, you would configure one HCA per node for redundancy.

CP and CUA

Currently, each pair of devices, whatever their implementation, is now referred to as a Channel Processor (CP). The even and odd address pair is also known as a channel unit address (CUA).

Software Components

The following figure illustrates the software components in channel-attached clients that play important roles in getting requests to and from the Teradata RDBMS.

Teradata RDBMS Database Administration

A - 23 Appendix A: Teradata RDBMS Configuration, Global Defaults, and Client Connections

Channel Environment

Channel-Attached System

Channel

KY01A023

The following table describes these software components:

Component Description
Client application • Written by a developer in your company • Written under contract to you by NCR • One of the Teradata RDBMS-provided utilities Users use these applications to submit SQL statements, maintain files, and generate reports. For details on supported programming languages, the Teradata Preprocessor2, and embedded SQL requirements, see Teradata Preprocessor2 Programmer Guide.
Call-Level Interface Version 2 (CLIv2) A low-level interface to the Teradata RDBMS. It consists of system calls that: • Create sessions • Allocate request and response buffers • Create and deblock parcels of information • Fetch response information for the requesting client. For more information, see Teradata Call-Level Interface Version 2 Reference for Channel-Attached Systems

Teradata RDBMS Database Administration A - 23 Appendix A: Teradata RDBMS Configuration, Global Defaults, and Client Connections

Channel Environment

Component Description
Teradata Director Manages communication between mainframe clients and the
Program (TDP) Teradata server. Functions include the following:
• Session initiation and termination
• Logging, verification, recovery, and restart of client
applications
• Physical input to/output from PE vprocs
• Security
• Session balancing across multiple PEs
• Control of the default client character set to be used during
sessions originating through this TDP (unless overridden by
the user with a BTEQ .SET SESSION CHARSET command)
For more information, see "TDP Functionality" on page A-26
and Teradata Director Program Reference.

Channel Sessions

A session number uniquely identifies the work stream of a session for a given TDP. A logical client number uniquely identifies each TDP within an MVS or VM client or multiple clients. A session number and a logical client number identify each session to the MVS or VM client.

You can request DBCTIME time stamps to record when:

• The TDP receives the request.

• The request was queued to the server.

• The server received the response.

• The response was queued to the cross memory task.

• The response was returned to the user's input (response) buffer.

Session Pools

A session pool is a number of sessions that are logged onto the Teradata RDBMS server as a unit, using the same logon string via a TDP START POOL command.

Unlike ordinary sessions, pool sessions are automatically assigned to applications that initiate a logon using the same logon string as that established for the pool. Every session in a pool is assigned to a specific PE and stays with that PE until the session ends.

When the pool is established, all sessions are not in use. When an application sends a logon request whose string matches that of the session pool, the application is assigned an available session from the pool.

That session is marked in-use and cannot be reassigned to another application until the current application logs off. Sessions pools remain logged on until you log them off with the STOP POOL or LOGOFF POOL commands.

Teradata RDBMS Database Administration

A - 23 Appendix A: Teradata RDBMS Configuration, Global Defaults, and Client Connections

TDP Functionality

TDP Functionality

All messages that a mainframe client sends or receives to Teradata RDBMS normally pass through the TDP. In addition to session, packet, and security control, mainframe TDPs are responsible for:

• Balancing sessions across assigned parsing engines

• Routing responses back to the originating address space

Also, you can request DBCTIME time stamps to record when:

• The TDP receives the request.

• The request was queued to the server.

• The server received the response.

• The response was queued to the cross-memory task.

• The response was returned to the user's input (response) buffer.

TDP Exits

An exit is a point at which a user request temporarily leaves the existing code to perform a user-specified task before continuing on with normal processing. You can define routines to perform some function or alteration of normal processing.
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