TS/MP System Management Manual (H06.05+, J06.03+)

SERVER Commands
HP NonStop TS/MP System Management Manual—541819-007
12-50
Usage Considerations for SET SERVER TIMEOUT
Attribute
Usage Considerations for SET SERVER
TIMEOUT Attribute
If a server process is delayed in its request processing (for example: when it is stuck
behind a lock, is blocked by a higher priority process, or due to any performance
pitfall), TS/MP may time out the request using the timeout value from either the SET
SERVER TIMEOUT configuration parameter or the timeout argument of a
SERVERCLASS_SEND_ call, SERVERCLASS_DIALOG_BEGIN_call or
SERVERCLASS_DIALOG_SEND_call.
Despite being timed out, the server may continue to process the request or continue to
be "stuck". Read-only type processing is especially vulnerable to these conditions.
When insert, update, or delete operations are being performed within a TMF
transaction and a timeout occurs, the TMF transaction will be aborted. Subsequent I/O
operations may then complete with file system error FEINVTRANSID, thereby
terminating processing. Read-only processing has no easy way to know that the server
request was cancelled, unless the server is multi-threaded and monitors $RECEIVE for
incoming messages and cancellations while processing its current request(s).
If MAXLINKS > 1, any requests queued on $RECEIVE will continue to queue there,
possibly up to the point of timing out themselves. Configuring MAXLINKS 1 for a server
class minimizes these additional effects.
Therefore, a single-threaded server is incapable of processing $RECEIVE “message
cancellation” system messages in a timely fashion.