當設置了resource_limit=true 。通過idle_time限制session idle 時間。session idle超過設置時間，狀態為sniped (v$session).,然而OS下的process并不會釋放，當session(user process) 再次與server process 通訊，將關閉相應的server process.

sqlnet.expire_time 的原理不一樣，Oracle Server 發送包探測dead connection ，如果連接關閉，或者不再用，則關閉相應的server process.

以上兩者組合使用，減少server process,防止process超過init$ORACLE_SID極限值。

#查找長時間不用的session.
SELECT?s.username,s.status,s.machine,osuser,spid,
'kill -9 '||spid UNIX_level_kill,
'alter system kill session '?||''''||s.sid||','||s.serial# ||?''';'?Oracle_level_kill,
TO_CHAR (logon_time,?'dd/mm/yyyy hh24:mi:ss') logon_time,
last_call_et idle_time,
TO_CHAR (TRUNC (last_call_et?/?3600,?0))||' '||' HRS '||TO_CHAR (TRUNC ((last_call_et?-?TRUNC(last_call_et?/?3600,?0)?*?3600)?/?60,?0)) ||' MINS'?idle_time_hour_minute,
module?
FROM?v$session?s, v$process p
WHERE?TYPE?=?'USER'
AND?p.addr?=?s.paddr
AND?status?=?'SNIPED'?
-- AND SUBSTR (machine, 1, 19) NOT IN ('machine')
AND?last_call_et?>?60?*?60?*?2
-- session idle time more than 1 hour
ORDER?BY?last_call_et?desc;

##寫了一個腳本,kill sniped session
##kill_sniped_session.sh
#! /bin/bash
ORACLE_SID=xxxxprod
export ORACLE_SID
ORACLE_HOME=`cat /var/opt/oracle/oratab|grep ^$ORACLE_SID:|cut -f2 -d':'`
export ORACLE_HOME
SQLPATH=/apps/oracle/sql
export SQLPATH
#
$ORACLE_HOME/bin/sqlplus -s "/ as sysdba"<<!
@sniped_session.sql?
exit
!
if [ -s /apps/oracle/sql/kill_sniped_session.lst ]?
then
echo "have a list of sniped_session"
grep kill /apps/oracle/sql/kill_sniped_session.lst
grep kill /apps/oracle/sql/kill_sniped_session.lst | awk '{ print $3 }' | xargs kill -9 2>/backup/oracle/kill_sniped_session.log
fi
if [ $? -ne 0 ]
then
cat /backup/oracle/kill_sniped_session.log | mailx -s "xxxxprod kill sniped session failed"?xx@@ss.com
else
sessions_count=`grep kill /apps/oracle/sql/kill_sniped_session.lst | wc -l`
echo "sessions:${sessions_count}" | mailx -s "xxxxprod kill sniped session successful"?xx@@ss.com
touch /backup/oracle/kill_sniped_session.sh
fi

oracle@xxxxprod$?more sniped_session.sql?
rem sniped_session.sql?
rem DESCRIPTION
rem kill sniped session
rem MODIFIED
set pagesize 1000
set heads off
set verify off
set heading off?
set termout off?
set echo off
set feedback off?
spool on
spool /apps/oracle/sql/kill_sniped_session.lst
select 'kill -9 '||spid UNIX_level_kill
FROM v$session s, v$process p
WHERE TYPE = 'USER'
AND p.addr = s.paddr
AND status = 'SNIPED'?
AND last_call_et > 60 * 60 * 3
ORDER BY last_call_et desc;
spool off

##btw

What does 'SNIPED' status in v$session mean?

When IDLE_TIME is set in the users' profiles or the default profile. This will kill the sessions in the database (status in v$session now becomes SNIPED) and they will eventually disconnect. It does not always clean up the Unix session (LOCAL=NO sessions). At this time all oracle resources are released but the shadow processes remains and OS resources are not released. This shadow process is still counted towards the parameters of init.ora.

This process is killed and entry from v$session is released only when user again tries to do something. Another way of forcing disconnect (if your users come in via SQL*Net) is to put the file sqlnet.ora on every client machine and include the parameter "SQLNET.EXPIRE_TIME" in it to force the close of the SQL*Net session

sqlnet.expire_time

sqlnet.expire_time actually works on a different principle and is used to detect dead connections?as opposed to?disconnecting(actually 'sniping') a session based on idle_time which the profile accomplishes.?

Sqlnet.expire_time basically instructs the Server to send a probe packet every set minutes to the client , and if it finds a terminated connection or a connection that is no longer in use, causes the associated server process to terminate on the server.?
A valid database connection that is idle will respond to the probe packet causing no action on the part of the Server , whereas the resource_limit will snipe the session when idle_time is exceeded.?The 'sniped' session will get disconnected when the user(or the user process) tries to communicate with the server again.
But again,as you mentioned, expire_time works globally while idle_time profile works for that user.?You can use both of them to make sure that the client not only gets sniped but also gets disconnected if the user process abnormally terminates.

總結

以上是生活随笔為你收集整理的sqlnet.expire_time and idle_time的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。