12537: TNS:connection closed错误处理过程

1，同事说Oracle测试换了连接不上了，报错如下 [oracle@pldb236 admin]$ rlwrap sqlplus powerdesk/pd141118@PD236 SQL*Plus: Release 11.2.0.1.0 Production on Mon Nov 23 14:16:31 2015 Copyright (c) 1982, 2009, Oracle. All rights reserved. ERROR: ORA-12537: TNS:connection closed Enter user-name:

检查监听正常，Oracle服务也是正常启动的，但是登录不进去

[oracle@pldb236 admin]$ tnsping PD236 TNS Ping Utility for Linux: Version 11.2.0.1.0 - Production on 23-NOV-2015 14:17:22 Copyright (c) 1997, 2009, Oracle. All rights reserved. Used parameter files: Used TNSNAMES adapter to resolve the alias Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.180.236)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = powerdes))) OK (10 msec) [oracle@pldb236 admin]$ 2，解决方案 [oracle@pldb236 bin]$ cd $ORACLE_HOME/bin/ [oracle@pldb236 bin]$ [oracle@pldb236 bin]$ [oracle@pldb236 bin]$ ll oracle -rwsr-s--x. 1 oracle oinstall 210823844 Jul 31 13:21 oracle [oracle@pldb236 bin]$ [oracle@pldb236 bin]$ chmod 6571 oracle [oracle@pldb236 bin]$ [oracle@pldb236 bin]$ ll oracle -r-srws--x. 1 oracle oinstall 210823844 Jul 31 13:21 oracle [oracle@pldb236 bin]$ [oracle@pldb236 bin]$ rlwrap sqlplus / as sysdba SQL*Plus: Release 11.2.0.1.0 Production on Mon Nov 23 14:20:09 2015 Copyright (c) 1982, 2009, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> SQL>

ok可以连接上了，问题初步解决

3，不过3分钟后，又不行了，登录不上去。

SQL*Plus: Release 11.2.0.1.0 Production on Mon Nov 23 14:29:17 2015

Copyright (c) 1982, 2009, Oracle. All rights reserved.

ERROR:
ORA-12537: TNS:connection closed

Enter user-name:

去查看lsnrctl状态：
[oracle@pldb236 bin]$ lsnrctl status

LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 23-NOV-2015 14:30:33 Copyright (c) 1991, 2009, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.180.236)(PORT=1521))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production Start Date 23-NOV-2015 14:30:19 Uptime 0 days 0 hr. 0 min. 13 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /oracle/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora Listener Log File /oracle/app/oracle/diag/tnslsnr/pldb236/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.180.236)(PORT=1521))) (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC0))) Services Summary... Service "PLSExtProc" has 1 instance(s). Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service... Service "powerdes" has 1 instance(s). Instance "powerdes", status UNKNOWN, has 1 handler(s) for this service... The command completed successfully [oracle@pldb236 bin]$

看到后台alert的日志报错如下：

Mon Nov 23 14:32:00 2015 ORA-00020: maximum number of processes 150 exceeded ORA-20 errors will not be written to the alert log for the next minute. Please look at trace files to see all the ORA-20 errors. Mon Nov 23 14:32:47 2015 Process m000 submission failed with error = 20 Mon Nov 23 14:33:02 2015 ORA-00020: maximum number of processes 150 exceeded ORA-20 errors will not be written to the alert log for the next minute. Please look at trace files to see all the ORA-20 errors. Mon Nov 23 14:34:03 2015 ORA-00020: maximum number of processes 150 exceeded ORA-20 errors will not be written to the alert log for the next minute. Please look at trace files to see all the ORA-20 errors.

解决方案1：
lsnrctl stop 5分钟后，再lsnrctl start起来，问题解决了，是应用程序一直不停的连接数据库，占满了连接池导致的。