解决方案2：
查看oracle的连接数，果然为150
分析原因：
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>修改配置文件：
[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 ~]$改动连接数，并且写入参数文件
alter system set processes=500 scope = spfile; SQL> alter system set processes=500 scope=spfile; System altered. SQL> create pfile from spfile; File created. SQL>关闭重启oracle实例，启动就可以看到最大连接数已经变成了500，问题解决
SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> exit Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options [oracle@pldb236 ~]$ 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>