Addressing OLTP Solutions with CICS: The Transaction Server ... - Ibm

More documents

Recommendations

Info

The ANIMATOR debugging tool enables you to test a Micro Focus COBOL application program online without modifying the program. This tool intercepts execution of the application program at various points before displaying information about the program. Any screens sent by the application program are displayed by the tools, so that you can converse with the application program during testing just as you would on the production system. The IBM Application Debugging Program provides the ability to debug IBM COBOL, C, or PL/I programs. There are a number of new facilities to go with the debugging tool: • A CICS-supplied transaction, CDCN, that turns the debugging tool on and off • A regionwide attribute, AllowDebugging with settings yes and no, to control whether the debugging tool can be used within the region. • Two transaction definitions (TD) entries: − DFHCDCN0 (for the CICS-supplied program) − DFHCDCN (for the CICS-supplied mapset) 10.6.4 Using Transactions to Call Your Program In CICS, the term transaction is used to describe a fundamental unit of work, consisting of one or more application programs, that is initiated by a single request. A transaction is identified by a transaction identifier (tranid), which is used to call your application program in the CICS run-time environment. Given that both the transaction and program are defined to CICS, you can use the cicsterm or cicsteld commands to run the transaction and therefore run your application program. The transaction is executed in the run-time environment under the control of CICS, which provides the services requested by each API command and dynamically changes the control parameters. 10.7 Designing Efficient Applications 10.7.1 CICS Transaction Design 150 CICS for AIX as the Transaction Server As in all design, there is a balance to be struck between the possibly conflicting requirements of performance, efficiency, ease of maintenance, productivity, readability of code, usability, standards, budgets, and schedules. The standards and guidelines of your organization, and the prioritization of design goals, will determine how much of this section you can apply in the applications you are developing. It is assumed here that you have already completed your system design to a logical level and are now trying to divide the application processing into CICS transactions and programs, its input and output into BMS maps, and its data into CICS data areas, files, temporary storage queues, and transient data queues. A primary consideration for online transactions is whether to design conversational or pseudo conversational transactions.
10.7.1.1 Pseudo Conversational and Conversational Transactions Pseudo conversational programming is based on the fact that, in a conversational transaction, the length of time spent in processing each of a user′s responses is extremely short when compared to the amount of time waiting for the input. A conversational transaction is one that involves more than one input from the terminal, so that the transaction and the user enter into a kind of conversation. A nonconversational transaction has only one input (the one that causes the transaction to be invoked). It processes that input, responds to the terminal, and terminates. In a conversational transaction, processor utilization times, even allowing for accessing files, are considerably shorter than terminal transmission times, which are considerably shorter than user response times. This is especially true if users have to think about the entry or enter many characters of input. Consequently, conversational transactions utilize storage and other resources for much longer than nonconversational transactions. A pseudo conversational transaction sequence contains a series of nonconversational transactions that look to the user like a single conversational transaction involving several screens of input. Each transaction in the sequence handles one input, sends back the response, and terminates. Before a pseudo conversational transaction terminates, it can pass data forward to be used by the next transaction initiated from the same terminal, whenever that transaction arrives. A pseudo conversational transaction can specify what the next transaction is to be, and it does this by setting the tranid of the transaction which is to handle the next input. However, be aware that if another transaction is started for that device, it may interrupt the pseudo conversational chain you have designed. No transaction exists for the terminal from the time a response is written until the user sends the next input and CICS starts the next transaction to respond to it. Information that would normally be stored in the program between inputs is passed from one transaction in the sequence to the next using the COMMAREA or one of the other facilities that CICS provides for this purpose. 10.7.1.2 Correspondence of CICS Client Processes and Servers In a typical CICS system there is likely to be a small pool of application servers servicing requests from a much larger pool of CICS cicsterm and cicsteld processes. It is important to understand that a conversational transaction requires exclusive use of an application server, thereby reducing the total number of servers available to process other requests. CICS will create additional servers as dictated by system demand up to a maximum number that you can configure, but once you reach this limit no more will be created. Therefore if you design all of your applications to be conversational, there is a considerable risk that CICS will be unable to service user requests to run transactions. Chapter 10. Application Design Considerations 151
Page 1:
Addressing OLTP Solutions with CICS
Page 4 and 5:
Take Note! Before using this inform
Page 6 and 7:
iv CICS for AIX as the Transaction
Page 8 and 9:
9.4 Security Issues on the Internet
Page 10 and 11:
viii CICS for AIX as the Transactio
Page 12 and 13:
x CICS for AIX as the Transaction S
Page 14 and 15:
xii CICS for AIX as the Transaction
Page 16 and 17:
The Team That Wrote This Redbook xi
Page 18 and 19:
xvi CICS for AIX as the Transaction
Page 20 and 21:
2 CICS for AIX as the Transaction S
Page 22 and 23:
1.2 Complex OLTP Business Environme
Page 24 and 25:
Figure 2. OLTP Complex for XYZ Insu
Page 26 and 27:
By using common application program
Page 28 and 29:
1.5 OLTP Market 10 CICS for AIX as
Page 30 and 31:
Figure 5. OLTP Market Segmentation
Page 32 and 33:
14 CICS for AIX as the Transaction
Page 34 and 35:
2.1 IBM Software Servers 2.1.1 Lotu
Page 36 and 37:
2.2.1 CICS Clients V1.1.0 A Transac
Page 38 and 39:
2.2.4 CICS Internet Gateway for AIX
Page 40 and 41:
3.1 Services CICS for AIX is a very
Page 42 and 43:
3.1.2 CICS API 24 CICS for AIX as t
Page 44 and 45:
3.1.3.1 Terminal Users and CICS Reg
Page 46 and 47:
3.2 Implementation 3.2.1 Components
Page 48 and 49:
3.2.2 Processes 3.2.1.3 Application
Page 50 and 51:
3.3.1 DCE RPC 3.3.2 TCP/IP 32 CICS
Page 52 and 53:
Figure 9. Interconnection Using Enc
Page 54 and 55:
connect to a PPC Gateway server mac
Page 56 and 57:
Figure 12. Interconnection Using TC
Page 58 and 59:
3.4.3 Configuration 3.4.4 Managing
Page 60 and 61:
3.4.6 Intersystem Communication CIC
Page 62 and 63:
3.4.8 Data Location 44 CICS for AIX
Page 64 and 65:
3.4.11 Operations plan to cope with
Page 66 and 67:
3.5 Summary 48 CICS for AIX as the
Page 68 and 69:
Figure 13. Application Server Model
Page 70 and 71:
4.2.1 CICS External Call Interface
Page 72 and 73:
By means of mapping files, you can
Page 74 and 75:
4.3 Versions 56 CICS for AIX as the
Page 76 and 77:
4.4 Sample Network Configurations 4
Page 78 and 79:
4.5.1 CICS Client for OS/2 60 CICS
Page 80 and 81:
4.5.2 CICS Client for DOS 62 CICS f
Page 82 and 83:
4.5.5 CICS Client for AIX CICS Clie
Page 84 and 85:
Page 86 and 87:
4.6 Summary 68 CICS for AIX as the
Page 88 and 89:
5.1.1 DCE Threads 5.1.2 Remote Proc
Page 90 and 91:
The GDS is based on the CCITT X.500
Page 92 and 93:
egion or server it is looking for.
Page 94 and 95:
Page 96 and 97:
6.1.2 Encina Toolkit Server Core 6.
Page 98 and 99:
Page 100 and 101:
is also necessary to use native AIX
Page 102 and 103:
Page 104 and 105:
7.1 X/Open XA Interface 7.1.1 X/Ope
Page 106 and 107:
Page 108 and 109:
Communication between the transacti
Page 110 and 111:
Page 112 and 113:
7.2.2 Single-Phase and Two-Phase co
Page 114 and 115:
Page 116 and 117:
Figure 28. Switching Access among D
Page 118 and 119: 100 CICS for AIX as the Transaction
Page 120 and 121: Figure 30. CICS Access to Remote DB
Page 122 and 123: emote DRDA database. Information ab
Page 124 and 125: As the COMMAREA has an allowable ma
Page 126 and 127: 7.5 Summary 108 CICS for AIX as the
Page 130 and 131: 8.2 Workload Management 112 CICS fo
Page 134 and 135: 8.4.2 System Management Application
Page 136 and 137: Figure 36. The CICS SM GUI 8.4.6 Di
Page 138 and 139: Figure 37. CICS SM Component Distri
Page 140 and 141: Figure 38. Combining Resources 122
Page 142 and 143: 8.5.2 The Reference System 124 CICS
Page 146 and 147: 8.6 Planning Considerations for CIC
Page 152 and 153: 9.1 Some Terminology 9.2 Services 1
Page 154 and 155: Figure 41. CICS Internet Gateway fo
Page 156 and 157: 9.3.3 Data Integrity The Web was or
Page 158 and 159: 9.3.5 High Availability The drawbac
Page 160 and 161: or employee records, eavesdropping
Page 164 and 165: • Type, size, and quantity of rec
Page 166 and 167: 10.3.3 Writing ECI and EPI Applicat
Page 172 and 173: 10.8 Summary 154 CICS for AIX as th
Page 176 and 177: 11.1 The Big Picture 158 CICS for A
Page 178 and 179: 11.2 User Access 160 CICS for AIX a
Page 180 and 181: Figure 44. Access to Various DB2 Da
Page 184 and 185: takes place over TCP/IP or SNA comm
Page 186 and 187: provide greater protection in the u
Page 194 and 195: How Customers Can Get ITSO Redbooks
Page 198 and 199: design. The process of composing a
Page 200 and 201: A year later ISC gave SQL formal in
Page 204 and 205: designing efficient applications 15
Page 206: IBML ® Printed in U.S.A. SG24-4752
show all

Addressing OLTP Solutions with CICS: The Transaction Server ... - Ibm

Create successful ePaper yourself

Delete template?

Save as template?