Error: Ora-12537:tns: Connection closed

Problem Description:

When I went to work this morning, I was suddenly told by my colleague that yesterday's good database was not connected properly. Connected items on the server did not report a connection failure, but normal data access was not possible. an "error:ORA-12537:TNS connection shutdown" error occurred while connecting through the PL/SQL tool .

Problem Analysis:

Because of the previous occurrence because the database monitoring suddenly hung up, resulting in a connection exception, although at that time through the PL/SQL tool to connect the times of the exception is not this, but in order to exclude this aspect, or check the following database monitoring situation.

by command lsnrctl status, it is normal to view the monitoring of the database.

Because the database cannot be connected through the PL/SQL Connection tool, all of them want to connect to the database through the DBA system user and check. After you execute the "sqlplus/as sysdba" command on the database server, theexception appears as follows:

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/72/29/wKioL1XeeKHTbgXgAADmmjMnc8k351.jpg "title=" Picture 1.png "alt=" Wkiol1xeekhtbgxgaadmmjmnc8k351.jpg "/>

See this error, it is understood that the database connection number is occupied, causing the connection to close the error.

Problem solving:

Immediately let the development side of the colleague, turn off connect this database test users, release some connections. Then, through the PL/SQL tool, connect to the database to see how many connections the current database server occupies.

Selectusername,Count(username) , Machine fromv$sessionGroup  byusername, Machine

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/72/2D/wKiom1XedpqRSh1PAAD2Gpruo2E911.jpg "title=" Picture 2.png "alt=" Wkiom1xedpqrsh1paad2gpruo2e911.jpg "/>

Find a machine with a large number of connections, check the corresponding server background log, found that the number of these connections are due to the program is not released in a timely manner caused.

Contact the developer to optimize the code.

This article is from the "Day of the Cold" blog, please be sure to keep this source http://yangsp.blog.51cto.com/9267470/1688749

Error: Ora-12537:tns: Connection closed