ORA-12537:TNS:connectionclosed错误处理过程

1，同事说oracle测试换了连接不上了，报错如下

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<code class=" hljs ruby">[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: </code>

检查监听正常，oracle服务也是正常启动的，但是登录不进去

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[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]$

PS：原blog地址：https://blog.csdn.net/mchdba/article/category/3254519，未经过原csdn的博主mchdba允许，谢绝转载

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2，解决方案

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[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

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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

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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：

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<code class=" hljs livecodeserver">        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.</code>

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。

解决方案2：
查看oracle的连接数，果然为150

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<code class=" hljs vhdl">SQL> show parameter processes;   NAME                     TYPE    VALUE ------------------------------------ ----------- ------------------------------ aq_tm_processes              integer     0 db_writer_processes          integer     2 gcs_server_processes             integer     0 global_txn_processes             integer     1 job_queue_processes          integer     1000 log_archive_max_processes        integer     4 processes                integer     150 SQL> SQL> SQL> </code>

分析原因：

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<code class=" hljs asciidoc">SQL> select count(1) from v$session t where t.status='INACTIVE' and t.username='PLAS';   COUNT(1) ----------         88   SQL> SQL> SQL> select count(1) from v$session t where t.status='INACTIVE' and t.username='PLAS';   COUNT(1) ----------          5   SQL> </code>

修改配置文件：

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<code class=" hljs ruby">[oracle@pldb236 ~]$ find /oracle -name *init.ora* /oracle/app/oracle/product/11.2.0/dbhome_1/dbs/init.ora /oracle/app/oracle/product/11.2.0/dbhome_1/srvm/admin/init.ora /oracle/app/oracle/admin/powerdes/pfile/init.ora.7112015171232 [oracle@pldb236 ~]$ </code>

改动连接数，并且写入参数文件

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<code class=" hljs oxygene">alter system set processes=500 scope = spfile; SQL> alter system set processes=500 scope=spfile;   System altered.   SQL> create pfile from spfile;   File created.   SQL> </code>

关闭重启oracle实例，启动就可以看到最大连接数已经变成了500，问题解决

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<code class=" hljs vhdl">SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> exit Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options [oracle@pldb236 ~]$ rlwrap sqlplus / as sysdba   SQL*Plus: Release 11.2.0.1.0 Production on Mon Nov 23 23:09:00 2015   Copyright (c) 1982, 2009, Oracle.  All rights reserved.   Connected to an idle instance.   SQL> startup; ORACLE instance started.   Total System Global Area 6680915968 bytes Fixed Size          2213936 bytes Variable Size        4362078160 bytes Database Buffers     2281701376 bytes Redo Buffers           34922496 bytes Database mounted. Database opened. SQL> SQL> SQL> show parameter processes;   NAME                     TYPE    VALUE ------------------------------------ ----------- ------------------------------ aq_tm_processes              integer     0 db_writer_processes          integer     2 gcs_server_processes             integer     0 global_txn_processes             integer     1 job_queue_processes          integer     1000 log_archive_max_processes        integer     4 processes                integer     500 SQL> </code>