Terminating Oracle connections with connect_time, idle_time, expire_time and
Oracle Database Tips by Burleson Consulting
January 29, 2015 - Updated September 10, 2015
Oracle has several ways to disconnect idle sessions, both
from within SQL*Plus via resources profiles (connect_time, idle_time),
and with the SQL*net expire time parameter.
Using the connect_time parameter
The connect_time parameter will disconnect a session
whose connect time exceed the value for connect_time. The connect_time
is expressed in minutes.
IMPORTANT NOTE: You must set
resource_limit=TRUE to automatically terminate Oracle connections.
system set resource_limit=true scope=both;
You can use profiles to set the connect time and idle time
with "alter profile" statements. Here we set the connect_time
to fire in 90 minutes:
profile senior_claim_analyst limit
Profiles comprise a named set of resource limits.
Also see these notes on the
default, when you create users, they are given the default profile, which
provides unlimited use of all resources.
The syntax to create a profile follows:
profile LIMIT resource_parameters|password_parameters;
By setting resource limits, you can prevent users from performing operations
that will tie up the system, and prevent other users from performing operations.
You can use resource limits for security, to ensure that users log off the
system, so as not to leave the session connected for long periods of time.
The system resource limits can be enforced at the session level, the call level,
or both. The session level is calculated from the time the user logs in to the
database until the user exits. The call level applies to each SQL command
issued. Session-level limits are enforced for each connection. When a session
level limit is exceeded, only the last SQL command issued is rolled back; no
further work can be performed until a commit, rollback, or exit is performed.
The sqlnet.expire_time parameter is used to set a time
interval, in minutes, to determine how often a probe should be sent verifying
that client/server connections are active. If you need to ensure that
connections are not left open indefinitely (or up to the time set by operating
system-specific parameters), you should set a value that is greater than 0. This
protects the system from connections left open due to an abnormal client
When the probe detects a terminated connection or a
connection no longer in use, it signals an error, causing the server process to
exit. This setting is intended for use on the database server side of the
connection, which usually handles multiple connections at any one time.
Limitations on using this terminated (dead) connection detection feature are:
sqlnet.expire_time cannot be used on bequeathed
The SQL*Net expire_time probe packet will
generate additional network traffic that may downgrade the network's
performance, depending on the number of connections.
Depending on the operating system that is in use,
additional server processing may need to be performed to distinguish the
connection probe from other events that occur. This overhead for detection
of probe events can result in downgraded network performance.
To set up these advanced features, simply edit your sqlnet.ora file. If
you are a beginner, follow this procedure:
Start the Oracle Network Manager GUI.
In the GUI navigator pane, expand the icons Local >
From the list on the right hand pane, select General.
Click on the Advanced tab.
Next, enter the values for the fields or options you
want to set.
When you are finished, choose File > Save Network
Configuration to write your changes to the sqlnet.ora file.
The sqlnet.ora inbound_connect_timeout
The sqlnet.ora inbound_connect_timeout parameter is used to
limit the time, set in seconds, for a client to connect with the database server
and provide the required authentication information.
To limit consumption of Oracle resources by unauthorized users and enable
an audit trail, you should set time-limit values for the
sqlnet.inbound_connect_timeout parameter in wall-clock seconds. (This parameter
does not have default values.)
Failure resulting from sqlnet.inbound_connect_timeout will throw a
ORA-03136 inbound connection timed out error.
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