||Oracle Tips by Burleson
Shared Server Connection
In a shared server or multithreaded server
connection the listener passes the connection request to a
dispatcher process that then passes it to one of several shared
services in a round-robin least busy methodology. Multiple users
share the same server process that connects to the database. For a
shared server connection the configuration of the client is
identical to the configuration of a dedicated client, the real
changes are in the database initialization file.
Under multi-threaded server there are
several server database initialization parameters that must be set
properly for MTS to work. These parameters are:
MTS_CIRCUITS.This is a derived value
from the value of SESSIONS, defaults to 0 if MTS not configured.
The Oracle parameter is CIRCUITS and should be used as this
form is deprecated. The CIRCUITS parameter controls the total
number of virtual circuits allowed in the database.
MTS_DISPATCHERS.This parameter tells
oracle the type and number of dispatchers to create for each
network protocol. This parameter becomes DISPATCHERS in Oracle
and this new form of the parameter should be used beginning with
Oracle release 9.0.1.
MTS_MAX_DISPATCHERS. Sets the maximum
number of dispatcher processes to be allowed to run
concurrently. In Oracle this becomes MAX_DISPATCHERS, This
defaults to 5 but there should be at least one dispatcher for
each protocol defined in the MTS_DISPATCHERS parameter. The
default value applies only if dispatchers have been configured
for the system. The value of MAX_DISPATCHERS should at least
equal the maximum number of concurrent sessions divided by the
number of connections for each dispatcher. For most systems, a
value of 250 connections for each dispatcher provides good
MTS_MAX_SERVERS. Sets the maximum
number of shared server processes. In Oracle this becomes
MAX_SHARED_SERVERS and defaults to either 20 or to twice the
value of SHARED_SERVERS (MTS_SERVERS). If artificial deadlocks
occur too frequently on your system, you should increase the
value of MAX_SHARED_SERVERS.
MTS_SERVERS. Sets the number of
shared connection servers to start when the database is started.
Defaults to one on a MTS configured system, 0 on a normal
system. In Oracle this becomes SHARED_SERVERS. Oracle will
automatically increase this value up to MAX_SHARED_SERVERS so
unless you know you will need more than the default leave it set
at the default.
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