TS/MP 2.5 Pathsend and Server Programming Manual

Designing Server Programs......................................................................................................42
Design Considerations........................................................................................................42
Server Program Structure.....................................................................................................46
Designing Applications for Batch Processing..............................................................................49
3 Writing Pathsend Requestors......................................................................50
The Pathsend Procedure Calls...................................................................................................50
Interprocess Communication in the Pathsend Environment.............................................................51
Basic Pathsend Programming...................................................................................................51
Programming for Failure Recovery........................................................................................52
Security Issues...................................................................................................................56
Avoiding Coded PATHMON Names....................................................................................57
Context-Sensitive Pathsend Programming....................................................................................57
Using Context-Sensitive Requestors With Context-Free Servers..................................................58
Resource Utilization............................................................................................................58
Programming for Failure Recovery........................................................................................58
ACS Restart Errors..............................................................................................................59
Cancellation of Server-Class Send Operations.......................................................................59
Writing Requestors That Interoperate With NonStop Tuxedo Servers..............................................59
4 Writing Pathway Servers............................................................................61
Basic Pathway Server Programming...........................................................................................61
Servers Shared by Different Types of Requestors.....................................................................61
Guardian Servers and Pathway Servers.................................................................................61
Server Stop Protocol...........................................................................................................62
Handling of Messages from $RECEIVE.................................................................................62
Pathsend Requestor Failures.................................................................................................62
ACS Subsystem Process Failures...........................................................................................62
ACS Subsystem Failures......................................................................................................62
Linkage Space Considerations.............................................................................................62
Considerations for Servers Used With SCREEN COBOL Requestors..........................................63
Consideration for Servers Used With RSC/MP Clients.............................................................63
Nested Servers..................................................................................................................63
Using Context-Free Servers With Context-Sensitive Requestors..................................................63
Considerations for Servers That Use the TMF Subsystem...............................................................64
Recommended Structure for Applications...............................................................................64
Writing a Server to Use the TMF Subsystem...........................................................................65
Using Audited and Nonaudited Files....................................................................................65
Locking Records.................................................................................................................66
Grouping Transaction Operations........................................................................................66
Servers as Process Pairs......................................................................................................67
Transaction Deadlocks........................................................................................................68
Considerations for Debugging Pathway Servers..........................................................................68
ACS Subsystem Process Timeouts.........................................................................................68
PATHMON Process Timeouts...............................................................................................69
Server Timeouts.................................................................................................................69
Avoiding Timeout Errors......................................................................................................69
Writing Context-Sensitive Servers..............................................................................................69
Functions of a Context-Sensitive Server..................................................................................70
Detecting a Newly Established Dialog..................................................................................70
Receiving, Servicing, and Replying to Messages in a Dialog....................................................70
Correlating Messages With a Dialog....................................................................................72
Continuing a Dialog...........................................................................................................72
Aborting a Dialog..............................................................................................................72
Terminating a Dialog..........................................................................................................72
Detecting an Aborted Dialog...............................................................................................72
4 Contents