Pathway/iTS System Management Manual (G06.24+)

Tuning Your System Using Statistics
HP NonStop Pathway/iTS System Management Manual—426748-002
5-3
Link Management
Requesting a New Link
When a terminal task requests a new link, the task joins both the link queue and the
server-class wait queue inside the TCP:
1. The TCP specifies a timeout value for the LINK queue.
2. After the timeout expires, the TCP issues the link request to the PATHMON
process.
3. The task remains on the LINK queue until:
•
The PATHMON process establishes the link.
•
The PATHMON process denies the request for a new link.
When a link to the server class is available, the task is activated and removed from the
queues. If a link to the server class in denied, control is passed to a SCREEN COBOL
error handling routine (if present); otherwise, the TERM is suspended.
To specify a timeout value, the TCP uses the value specified with the SET SERVER
CREATEDELAY command, but only if the number of existing links to the server class
is greater than 0 and greater than the maximum number of static links available to the
TCP for that server class. Otherwise, the TCP sets the time-out value to 0.
The CREATEDELAY parameter specifies the maximum amount of time a link manager
waits to use an established link to a server class before requesting a new link from the
PATHMON process.
Granting a New Link
For the PATHMON process to grant a new link, the TCP must have enough resources
to support the new link:
•
The number of links from the TCP to all server processes at the time of the request
is fewer than that specified by the SET TCP MAXSERVERPROCESSES
command.
•
The number of server classes represented by processes that are linked to the TCP
is fewer than that specified by the SET TCP MAXSERVERCLASSES command.
If the PATHMON process grants a new link, it designates the link as either static or
dynamic:
•
A static link is usually not dissolved unless an error occurs over that link.
Initially, you set the maximum number of static links for a server class with the SET
SERVER NUMSTATIC command. Later, after examining information returned from
the PATHMON process, you can adjust the maximum number of static links.
•
A dynamic link is dissolved after it remains idle for a specified time period.