B4AppD TDP

Appendix D

TDP Operations

After completing this appendix, you will be able to:

Describe how the Teradata database is accessed through channel-attached clients.

Discuss the function of the Teradata Director program (TDP) and how it processes parcels.

Describe how Teradata returns answer sets to the client system.

Describe how the Teradata database is accessed through network-attached clients.

Discuss how to use session pools, including how to start and stop them.

Channel Environment

AS AS AS AS AS

TSO CICS IMS/DC

CLI CLI CLI CLI

ITEQBTEQ

orCoordinated

Products

CICSTransactions

IMSMPP / BMP

Pre-Processed

Batchor

TeradataUtilities

( TDP)Teradata

Director

Program

OS390

SYSTEMCONSOLE

BLOCK MULTIPLEXOR CHANNEL

CROSS MEMORY SERVICES (XMS)

Node

RDBMS

PE16383

PE16382

GatewaySoftware

PE PE

HostNo 52 HostNo 512

16381 16380

Channel DriverSoftware

Sending Parcels to the TDP

USER REGION TDP REGION

APPLICATION TDP

USER

CODE

RESPONSE BUFFER

REQUEST BUFFER

REQ PARCEL(SQL TEXT)

RESPONDPARCEL

FUNCTION CODE

SESSION NUMBER

REQUEST NUMBER

TIMESTAMP FIELDS

CONTEXT AREA

CLIMoves Parcels (SQL statements)into application REQUEST BUFFER.The RESPOND parcel indicatesthe size of the RESPONSE BUFFER.

REQUESTPARCEL

MESSAGEHEADER

OTHERREQUESTS

OTHERREQUESTS

HEADER CHANNEL BLOCK

RDBMS

PE PE

RESPONDPARCEL

HSICB

MESSAGE

Communicating with the TDP

From an MVS host console:

F Tdpid, TDPcommandtext

Where:

• F is the abbreviation for MVS modify.

• Tdpid is the four-character identifier for the TDP subsystem.

• TDPcommandtext is the syntax of the TDP command.

In a VM environment:

Tdpid, TDPcommandtext

Where:

• Tdpid is the four-character identifier for the TDP subsystem.

• TDPcommandtext is the syntax of the TDP command.

TDP Operator Commands

TDP

Display Module

RUNSHUTDOWN

CANCELQUIckOrderly

SET UseridSET CharsetSET Comchar

IFP

ATTachDETachDisplaySTArtSTOp

POOL

ENAbleDISAbleDisplayLOGOFFMODIFYSTArtSTOp

2PC

COMMITENAble IRFDISAble IRFDISPLAY INDoubtROLLBACK

Display TDP

CELLS

DisplayADD CELLS

LOGONS

DISAbleENAble

QUEUES

Display

SMF

ENAbleDISAbleDisplay ADD XMSCELLS

SESsion / JOB

DisplayLOGOFFSET MAXSESSDISABLE SESSION RESERVEENABLE SESSION RESERVEDISABLE SESSION DETAILENABLE SESSION DETAILDISABLE SESSION STATUSENABLE SESSION STATUS

TEST

ENAbleDISAble

EXITS

ENAbleDISAble

USERIDALLJOB

TIME

ENAbleDISAble

AUTHORIZ

MODIFYDISABLEENABLE

SAF

DISPLAY

CHANNEL PROCESSORS

DISPLAY

SESSION PROCESSORS

Sessions and Session Pools

A session is:

– A logical connection between the user and the database that permits a user one request and one response at a time.

– Sessions are explicitly logged on to and off from the database and are identified by a logical client ID and a session number.

A session pool is:

– A number of sessions using the same logon string that are logged on to the database using a START POOL command.

– To log off a session pool, use the LOGOFF or STOP POOL command.

– When you run a session pool, the TDP does not notify the database when an application logs off. It marks the session, “not in use” and makes it available to another application.

Starting a Session Pool

Start Pool Num 8 LOGON Orders, xxxxxxxxx16:51:24 T: TDP0865 STARTING POOL ID: POOL000216:51:24 T: TDP0866 ADDING 0008 SESSIONS TO POOL ID: POOL000216:51:25 T: TDP0899 SESSION 1288 STARTED, JOB POOL000216:51:25 T: TDP0899 SESSION 1289 STARTED, JOB POOL000216:51:26 T: TDP0899 SESSION 1290 STARTED, JOB POOL000216:51:26 T: TDP0899 SESSION 1291 STARTED, JOB POOL0002 :

::.;

POOL ID: POOL0002SESSION NUMBERS1288, 1289, 1290, 1291,1292, 1293, 1294, 1295

T D P

PE

SESSION 1288SESSION 1292

PE


PE


PE


Using a Session Pool

.LOGON ORDERS xxxxxxxxx .LOGON ANOTHER, yyyyyyyyy

.POOL ID: POOL0002

SESSION NUMBERS1288, 1289, 1290, 1291,1292, 1293, 1294, 1295

T D P

PE


PE

SESSION 1289SESSION 1293SESSION 1904

PE


PE


.SESSION CONTROL

SESSION NUMBERS1904

• Using a session pool typically saves 2 to 3 seconds logon time.

• If all the sessions in the pool are active, additional logons fail.

• If sessions in the pool are disabled, logons fail.

Ending a Session Pool

Stop Pool ID Pool000220:02:24 T: TDP0867 STOPPING POOL ID: POOL000220:02:24 T: TDP861 POOL ID: POOL002 IS NOW: STOPPED20:02:25 T: TDP0898 SESSION 1295 ENDED, JOB POOL0002 RC=000020:02:25 T: TDP0898 SESSION 1294 ENDED, JOB POOL0002 RC = 000020:02:26 T: TDP898 SESSION 1293 ENDED, JOB POOL0002 RC = 000020:02:26 T: TDP0898 SESSION 1292 ENDED, JOB POOL0002 RC = 000020:02:27 T: TDP0898 SESSION 1291 ENDED, JOB POOL0002 RC = 0000

T D P

PE PE

SESSION 1904

PE PE

.SESSION CONTROL

SESSION NUMBERS1904

DISABLE POOL Disables Logons but does not end pool.

STOP POOL Logs off unused sessions and disables new logons. When all sessions have logged off, the pool is ended.

LOGOFF POOL Logs off active sessions and ends pool.

TDP Memory Management

The TDP typically uses a virtual region of about 4 to 5 Megabytes.

To avoid overhead calls to the operating system, the TDP divides its work areas in cells.

PROGRAMSTORAGE

320K

FREESTORAGE

500K

CELLS

A warning message (TDP0021) displays when 80% of the cells of a certain size are in use. appearing when

D CELLS

TDP0501 CELSZ AVAIL INUSE MXUSE GMAIN XMS #WAITSTDP0528 00064 00062 00002 00003 00000 00000 00000TDP0528 00128 00050 00014 00017 00000 00000 00000TDP0528 00240 00032 00032 00032 00000 00000 00000TDP0528 00256 00320 00056 00077 00000 00200 00000TDP0528 00352 00480 00032 00032 00000 00200 00000TDP0528 00992 01331 00013 00013 00000 00300 00000TDP0528 12272 00009 00001 00006 00000 00000 00000

TDP0529 OVERSIZE CELLS, INUSE : 1, MXUSE: 1, GETMAINS : 1

ADD CELLS SIZE 256 NUMBER 1

This command adds an “extent” of sixteen 256 byte cells.

Client Configuration Overview Summary

The Teradata Channel Interface is an architecture that enables communication between a mainframe clienta Teradata server.

The Teradata Director Program (TDP) resides on themainframe and manages communication between the client application programs and the Teradata server.

The Micro Teradata Director Program resides on the network and parcels user requests. It then sends them to the gateway, and on to the parsing engine (PE).

A session is a logical connection between the userand the database. It permits a user one requestand one response at a time. Users must logon and logoff from sessions; sessions are identified by a client ID and session number.

A session pool is a number of sessions logged on tothe Teradata server as a unit using the same logon string. Session pools are logged on and off from the database. The TDP does not notify the database when an application logs off, but instead marks the session as ‘not in use.’

Review Questions

1. The Teradata Director Program (TDP) facilitates communication between LAN clients and the Teradata database.

2. WorldMark servers can use either ESCON or Bus and Tag channel connections to connect to a mainframe host.

3. You can enter TDP commands from MVS and VM consoles before the RUN command.

T F

T F

T F

Indicate whether a statement is True (T) or False (F).

Module 9 Review QuestionsSolutions

1. The Teradata Director Program (TDP) facilitates communication between LAN clients and the Teradata database.

2. WorldMark servers can use either ESCON or Bus and Tag channel connections to connect to a mainframe host.

3. You can enter TDP commands from MVS and VM consoles before the RUN command.

T F

T F

T F

Indicate whether a statement is True (T) or False (F).

Documents

B4AppD TDP