| BEA WebLogic Server 9.1 Domain Configuration Schema Reference | ||||||
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Determines whether the JMS server delivers smaller messages
before larger ones when a destination has exceeded its maximum
number of messages. FIFO
prevents the JMS server from
delivering smaller messages when larger ones are already waiting
for space. Preemptive
allows smaller send requests to
preempt previous larger ones when there is sufficient space for
smaller messages on the destination.
This policy is defined only for the JMS server; it cannot be set on individual destinations.
Additional information on the FIFO
and
Preemptive
policies is provided below.
FIFO
(first in, first out) indicates that all send
requests for the same destination are queued up one behind the
other until space is available. No send request is permitted to
successfully complete if there is another send request waiting for
space before it. When space is limited, the FIFO policy prevents
the starvation of larger requests because smaller requests cannot
continuously use the remaining available space. Smaller requests
are delayed, though not starved, until the larger request can be
completed. When space does become available, requests are
considered in the order in which they were made. If there is
sufficient space for a given request, then that request is
completed and the next request is considered. If there is
insufficient space for a given request, then no further requests
are considered until sufficient space becomes available for the
current request to complete.
Preemptive
indicates that a send operation can
preempt other blocking send operations if space is available. That
is, if there is sufficient space for the current request, then that
space is used even if there are other requests waiting for space.
When space is limited, the Preemptive policy can result in the
starvation of larger requests. For example, if there is
insufficient available space for a large request, then it is queued
up behind other existing requests. When space does become
available, all requests are considered in the order in which they
were originally made. If there is sufficient space for a given
request, then that request is allowed to continue and the next
request is considered. If there is insufficient space for a given
request, then that request is skipped and the next request is
considered.
"FIFO", "Preemptive"
| BEA WebLogic Server 9.1 Domain Configuration Schema Reference | ||||||
DETAILS: DOCUMENTATION | ELEMENTS | ATTRIBUTES | FRAMES | NO FRAMES |
Version: 9.1