应用一直好好的，突然有一天，日志中开始时不时的出现ora-03135，奇了怪。查了一下——
bash-2.05$ oerr ora 3135
03135, 00000, "connection lost contact"
// *Cause: 1) Server unexpectedly terminated or was forced to terminate.
// 2) Server timed out the connection.
// *Action: 1) Check if the server session was terminated.
// 2) Check if the timeout parameters are set properly in sqlnet.ora.
在$ORACLE_HOME/network/admin/sample/sqlnet.ora中找了一下有这一小节——
########################
#sqlnet.expire_time = 10
########################
#
#Possible values: 0-any valid positive integer! (in minutes)
#Default: 0 minutes
#Recommended value: 10 minutes
#
#Purpose: Indicates the time interval to send a probe to verify the
# client session is alive (this is used to reclaim watseful
# resources on a dead client)
#
#Supported since: v2.1
于是，在sqlnet.ora中加入
sqlnet.expire_time = 10
重启listener
bash-2.05$ lsnrctl reload
……
The command completed successfully
观察两天，日志中未再报ora-03135错误了。
文章出处：DIY部落(http://www.diybl.com/course/7_databases/oracle/oraclejs/2008727/134173.html)