警告日志里頻繁出現(xiàn)以下報錯：WARNING: inbound connectiontimed out (ORA-3136)

先去mos查詢文檔：

The following are the most likely reasons for this error -

• Very often this error is thrown because a client or application is attempting to connect using the wrong userid or password.
  See the following: Note: 793259.1 ORA-1017 May Cause ORA-3136 WARNING : Inbound Connection Timed Out in Alert Log

• The server receives a valid client connection request but the client takes a long time to authenticate more than the default 60 seconds.

• The DB server is heavily loaded due to which it cannot finish the client logon within the timeout specified.

To understand what is causing this issue, following checks can be done

The default value of 60 seconds is good enough in most conditions for the database server to authenticate a client connection. If it is taking longer, then it's worth checking the following items before implementing the workaround:
1. Check whether local connection on the database server is successful & quick.
2. If local connections are quick ,then check for underlying network delay with the help of your network administrator.
3. Check whether your Database performance has degraded.
4. Check alert log for any critical errors for eg, ORA-600 or ORA-7445 and get them resolved first.
These critical errors might have triggered the slowness of the database server.

To set these parameters to use values higher than the default of 60 seconds, follow these instructions:
Edit the server side sqlnet.ora file and add this parameter. It is important to note that in RAC the database
will reference a sqlnet.ora file in its own home and not in Grid where the listener is running.

So to be clear, add this line to the sqlnet.ora file in $RDBMS_HOME/network/admin:
SQLNET.INBOUND_CONNECT_TIMEOUT=<n> Where <n> is the value in seconds.

大概意思就是主要為在指定時間（默認為60秒）內(nèi)客戶端沒有成功連接上服務(wù)器導(dǎo)致，可能是DB負載比較高，或者網(wǎng)絡(luò)延時等造成。

解決辦法是：

修改sqlnet.ora文件，添加
SQLNET.INBOUND_CONNECT_TIMEOUT=180參數(shù)。