Oracle告警日志ora-04030

一oracle 11g 出现ORACLE ORA-04030之 out of process memory when trying to allocate报错，查询ORACLE官方MOS确定是：BUG11852492，原因是用户会话单进程占用PGA超过4GB异常终止，根据MOS文章1325100.1的建议：可以根据服务器实际情况及SQL运行的实际情况放开PGA单进程使用内存空间的限制到16GB。

相关分析处理过程如下：

ORA4030告警，告警信息如下：**************************** 查看数据库告警日志 ************************** ERROR IN ALERT LOG FILE - LAST 3 DAYS ===================================== 15/12/2016 22:44:13 Thu Dec 15 22:44:13 2016 Thu Dec 15 22:44:13 2016 ORA-04030: out of process memory when trying to allocate 64 bytes (kxs-heap-c,allocator state) ORA-04030: out of process memory when trying to allocate 624 bytes (kxs-heap-c,MSQ2) ORA-04030: out of process memory when trying to allocate 82456 bytes (pga heap,control file i/o buffer) Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl2/incident/incdir_498/orcl_pmon_60993.trc: See Note 411.1 at My Oracle Support for error and packaging details. Use ADRCI or Support Workbench to package the incident.

针对PGA单进程4GB内存空间的限制，查证当前操作系统相关限制参数设置为4GB：

[root@host ~]# more /proc/sys/vm/max_map_count65530[root@host ~]#  more /proc/sys/vm/max_map_count65530[root@host ~]#

针对PGA单进程4GB内存空间的限制，使用如下sql语句查证oracle数据库相关隐含参数设置为4GB：

_realfree_heap_pagesize_hint=65536 select a.ksppinm name, b.ksppstvl value, a.ksppdesc description  from x$ksppi a, x$ksppcv b where a.indx = b.indx and a.ksppinm like '_realfree_heap_pagesize_hint';

如果实际情况可以，oracle官方允许PGA单进程设置为16GB，相关操作如下：

SOLUTION Change the upper limit at either the OS or at the database level: Change the page count at the OS level: more /proc/sys/vm/max_map_count sysctl -w vm.max_map_count=262144 (for example) **Please note the above changes will revert upon host reboot unless the changes are permanently made in the /etc/sysctl.conf file ** Adjust the realfree heap pagesize within the database by setting the following parameters in the init/spfile and restart the database. For versions 11.2.0.4 and lower: _use_realfree_heap=TRUE _realfree_heap_pagesize_hint = 262144 For 12.1 and higher: _use_realfree_heap=TRUE _realfree_heap_pagesize = 262144