ORA-00020: No more process state objects available故障一例


今天一网友咨询数据库宕机了，当时数据库出现用户无法登录的症状，为了了解起因，去查看了网友的告警日志alert.log，发现在晚上10:00左右出现大量的ORA-00020: No more process state objects available 错误，具体错误日志如下:

Fatal NI connect error 12170.

  VERSION INFORMATION:
  TNS for Linux: Version 11.2.0.2.0 - Production
  Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.2.0 - Production
  TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.2.0 - Production
  Time: 11-MAY-2015 14:28:28
  Tracing not turned on.
  Tns error struct:
    ns main err code: 12535
   
 TNS-12535: TNS:operation timed out
    ns secondary err code: 12560
    nt main err code: 505
   
 TNS-00505: Operation timed out
    nt secondary err code: 110
    nt OS err code: 0
  Client address: (ADDRESS=(PROTOCOL=tcp)(HOST=192.168.102.150)(PORT=50069))
 Mon May 11 16:21:14 2015
 Thread 1 cannot allocate new log, sequence 1728
 Private strand flush not complete
  Current log# 4 seq# 1727 mem# 0: /oradata/orcl/redo4.log
 Thread 1 advanced to log sequence 1728 (LGWR switch)
  Current log# 3 seq# 1728 mem# 0: /oradata/orcl/redo3.log
 Mon May 11 22:00:00 2015
 Setting Resource Manager plan SCHEDULER[0x3107]:DEFAULT_MAINTENANCE_PLAN via scheduler window
 Setting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter
 Mon May 11 22:00:00 2015
 Starting background process VKRM
 Mon May 11 22:00:00 2015
 VKRM started with pid=83, OS id=27195
 Tue May 12 00:56:23 2015
 Thread 1 cannot allocate new log, sequence 1729
 Private strand flush not complete
  Current log# 3 seq# 1728 mem# 0: /oradata/orcl/redo3.log
 Thread 1 advanced to log sequence 1729 (LGWR switch)
  Current log# 1 seq# 1729 mem# 0: /oradata/orcl/redo01.log
 Tue May 12 02:00:00 2015
 Closing scheduler window
 Closing Resource Manager plan via scheduler window
 Clearing Resource Manager plan via parameter
 Tue May 12 10:46:48 2015
 Thread 1 cannot allocate new log, sequence 1730
 Private strand flush not complete
  Current log# 1 seq# 1729 mem# 0: /oradata/orcl/redo01.log
 Thread 1 advanced to log sequence 1730 (LGWR switch)
  Current log# 2 seq# 1730 mem# 0: /oradata/orcl/redo2.log
 Tue May 12 14:36:13 2015
 Thread 1 cannot allocate new log, sequence 1731
 Private strand flush not complete
  Current log# 2 seq# 1730 mem# 0: /oradata/orcl/redo2.log
 Thread 1 advanced to log sequence 1731 (LGWR switch)
  Current log# 4 seq# 1731 mem# 0: /oradata/orcl/redo4.log
 Tue May 12 16:27:07 2015
 Thread 1 cannot allocate new log, sequence 1732
 Private strand flush not complete
  Current log# 4 seq# 1731 mem# 0: /oradata/orcl/redo4.log
 Thread 1 advanced to log sequence 1732 (LGWR switch)
  Current log# 3 seq# 1732 mem# 0: /oradata/orcl/redo3.log
 Tue May 12 22:00:00 2015
 Setting Resource Manager plan SCHEDULER[0x3108]:DEFAULT_MAINTENANCE_PLAN via scheduler window
 Setting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter
 Tue May 12 22:00:00 2015
 Starting background process VKRM
 Tue May 12 22:00:00 2015
 VKRM started with pid=174, OS id=25804
 Wed May 13 02:00:00 2015
 Closing scheduler window
 Closing Resource Manager plan via scheduler window
 Clearing Resource Manager plan via parameter
 Wed May 13 02:45:10 2015
 Thread 1 cannot allocate new log, sequence 1733
 Private strand flush not complete
  Current log# 3 seq# 1732 mem# 0: /oradata/orcl/redo3.log
 Thread 1 advanced to log sequence 1733 (LGWR switch)
  Current log# 1 seq# 1733 mem# 0: /oradata/orcl/redo01.log
 Wed May 13 09:05:36 2015
 Time drift detected. Please check VKTM trace file for more details.
 Wed May 13 09:15:55 2015
 DM00 started with pid=352, OS id=4784, job SYSTEM.SYS_EXPORT_SCHEMA_01
 Wed May 13 09:15:56 2015
 DW00 started with pid=353, OS id=4786, wid=1, job SYSTEM.SYS_EXPORT_SCHEMA_01
 Wed May 13 10:11:52 2015
 Thread 1 cannot allocate new log, sequence 1734
 Private strand flush not complete
  Current log# 1 seq# 1733 mem# 0: /oradata/orcl/redo01.log
 Thread 1 advanced to log sequence 1734 (LGWR switch)
  Current log# 2 seq# 1734 mem# 0: /oradata/orcl/redo2.log
 Wed May 13 13:15:38 2015
 Thread 1 cannot allocate new log, sequence 1735
 Private strand flush not complete
  Current log# 2 seq# 1734 mem# 0: /oradata/orcl/redo2.log
 Thread 1 advanced to log sequence 1735 (LGWR switch)
  Current log# 4 seq# 1735 mem# 0: /oradata/orcl/redo4.log
 Wed May 13 14:54:18 2015
 Thread 1 cannot allocate new log, sequence 1736
 Private strand flush not complete
  Current log# 4 seq# 1735 mem# 0: /oradata/orcl/redo4.log
 Thread 1 advanced to log sequence 1736 (LGWR switch)
  Current log# 3 seq# 1736 mem# 0: /oradata/orcl/redo3.log
 Wed May 13 17:39:31 2015
 Thread 1 cannot allocate new log, sequence 1737
 Private strand flush not complete
  Current log# 3 seq# 1736 mem# 0: /oradata/orcl/redo3.log
 Thread 1 advanced to log sequence 1737 (LGWR switch)
  Current log# 1 seq# 1737 mem# 0: /oradata/orcl/redo01.log
 Wed May 13 20:47:10 2015
 ORA-00020: No more process state objects available
 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.
 Process m000 submission failed with error = 20
 Wed May 13 20:52:37 2015
 ORA-00020: No more process state objects available
 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.
 Process m000 submission failed with error = 20
 Wed May 13 20:57:38 2015
 ORA-00020: No more process state objects available
 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.
 Process m000 submission failed with error = 20
 Wed May 13 21:01:35 2015
 ORA-00020: No more process state objects available
 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.
 Process W001 submission failed with error = 20
 Wed May 13 21:02:38 2015
 ORA-00020: No more process state objects available
 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.
 Process m001 submission failed with error = 20
 Wed May 13 21:05:44 2015
 ORA-00020: No more process state objects available
 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.
 Process W001 submission failed with error = 20
 Wed May 13 21:12:38 2015
 ORA-00020: No more process state objects available
 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.
 Process m000 submission failed with error = 20
 Process m001 submission failed with error = 20
 Wed May 13 21:42:39 2015
 ORA-00020: No more process state objects available
 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.
 Process m000 submission failed with error = 20
 Process m001 submission failed with error = 20
 Wed May 13 21:43:00 2015
 Process W001 submission failed with error = 20
 Wed May 13 21:51:13 2015
 Adjusting the default value of parameter parallel_max_servers
 from 1280 to 385 due to the value of parameter processes (400)
 Starting ORACLE instance (normal)
 Wed May 13 21:52:40 2015
 ORA-00020: No more process state objects available
 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.
 Process m000 submission failed with error = 20
 Wed May 13 21:53:33 2015
错误信息一般在Oracle实例在创建一些辅助后台进程(如mmon的子进程m00x或者子进程W00x等)时出现进程启动失败时出现，而造成该错误的可能性有多种，包括Oracle实例资源不足、操作系统资源不足等等。其中较为常见的是实例instance的process使用达到上限，可以通过查询v$resource_limit视图来了解实例生命周期内是否发生过process总数暴满的情况:

我们可以看到processes的MAX_UTILIZATION最大使用数目曾到过LIMIT_VALUE限定的400，
 sessions达到了640.

从以上V$resource_limit视图的输出来看，极有可能是processes总数达到上限导致了新的后台辅助进程创建失败，其实我们可以很方便地验证这一点:

[oracle@bntjftest ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Thu May 14 15:28:15 2015

Copyright (c) 1982, 2013, Oracle.  All rights reserved.


 Connected to:
 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
 With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> select * from v$version;

BANNER
 --------------------------------------------------------------------------------
 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
 PL/SQL Release 11.2.0.4.0 - Production
 CORE 11.2.0.4.0 Production
 TNS for Linux: Version 11.2.0.4.0 - Production
 NLSRTL Version 11.2.0.4.0 - Production

SQL> show parameter processes

NAME        TYPE  VALUE
 ------------------------------------ ----------- ------------------------------
 aq_tm_processes        integer  1
 db_writer_processes      integer  1
 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> alter system set processes=40 scope=spfile;

System altered.

SQL> startup force;
 ORACLE instance started.

Total System Global Area 1987563520 bytes
 Fixed Size      2254584 bytes
 Variable Size  1224739080 bytes
 Database Buffers  754974720 bytes
 Redo Buffers      5595136 bytes
 Database mounted.
 Database opened.
 SQL> select resource_name,MAX_UTILIZATION,LIMIT_VALUE from v$resource_limit where resource_name in ('processes','sessions');


 RESOURCE_NAME        MAX_UTILIZATION LIMIT_VALUE
 ------------------------------ --------------- --------------------
 processes        24        40
 sessions        25      556

SQL> show parameter proce

NAME        TYPE  VALUE
 ------------------------------------ ----------- ------------------------------
 aq_tm_processes        integer  1
 cell_offload_processing      boolean  TRUE
 db_writer_processes      integer  1
 gcs_server_processes      integer  0
 global_txn_processes      integer  1
 job_queue_processes      integer  1000
 log_archive_max_processes      integer  4
 processes        integer  40
 processor_group_name      string

 SQL> select resource_name,MAX_UTILIZATION,LIMIT_VALUE from v$resource_limit where resource_name in ('processes','sessions');

RESOURCE_NAME        MAX_UTILIZATION LIMIT_VALUE
 ------------------------------ --------------- --------------------
 processes        40        40
 sessions        45      556

SQL>
客户端连接时，报下如的错误。


alter文件中的预警信息如下：
Thu May 14 15:39:32 2015
 SMCO started with pid=37, OS id=19445
 Thu May 14 15:44:30 2015
 ORA-00020: maximum number of processes (40) 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.
 Process m000 submission failed with error = 20
 Thu May 14 15:49:30 2015
 ORA-00020: maximum number of processes (40) 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.
 Process m000 submission failed with error = 20
 Thu May 14 15:59:30 2015
 ORA-00020: maximum number of processes (40) 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.
 Process m000 submission failed with error = 20
 Process m001 submission failed with error = 20
 Thu May 14 16:00:30 2015
 Process m000 submission failed with error = 20
 Thu May 14 16:01:30 2015
 ORA-00020: maximum number of processes (40) 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.
 Process m000 submission failed with error = 20
 Thu May 14 16:03:31 2015
 ORA-00020: maximum number of processes (40) 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.
 Process m000 submission failed with error = 20
 Thu May 14 16:04:31 2015
 Process m000 submission failed with error = 20
例子中我们可以清楚地了解到是因为数据库在实际运行中出现了processes进程总数达到参数设定上限从而导致问题出现，那么可以合理增加初始化参数processes或者通过修正异常频繁的程序客户端登录来解决该问题。

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