9i出現記憶體分配錯誤

在9.2.0.8 RAC環境中，告警日誌頻繁出現記憶體分配錯誤的資訊。

錯誤資訊如下：

Wed May 2 10:20:43 2012
Trace dumping is performing id=[cdmp_20120502102043]
There are 1444 memory allocation errors for object-level stat
in the last 15 minutes
.
.
.
There are 1605 memory allocation errors for object-level stat
in the last 15 minutes

在另外一個節點上則出現了ORA-4031錯誤：

Sun Apr 29 22:30:52 2012
Errors in file /oracle/admin/orcl/bdump/orcl2_j000_1204632.trc:
ORA-12012: error on auto execute of job 527
ORA-04031: unable to allocate 4224 bytes of shared memory ("shared pool","unknown object","sga heap(2,0)","object level s")
ORA-06512: at "PERFSTAT.STATSPACK", line 2479
ORA-06512: at "PERFSTAT.STATSPACK", line 91
ORA-06512: at line 1
Sun Apr 29 23:03:14 2012
Errors in file /oracle/admin/orcl/bdump/orcl2_j001_1528536.trc:
ORA-12012: error on auto execute of job 527
ORA-04031: unable to allocate 4256 bytes of shared memory ("shared pool","unknown object","sga heap(2,0)","obj stat memor")
ORA-06512: at "PERFSTAT.STATSPACK", line 2479
ORA-06512: at "PERFSTAT.STATSPACK", line 91
ORA-06512: at line 1
There is 1 memory allocation error for object-level stat
in the last 15 minutes
There are 66 memory allocation errors for object-level stat
in the last 15 minutes
There are 8 memory allocation errors for object-level stat
in the last 15 minutes
Mon Apr 30 00:07:38 2012
Errors in file /oracle/admin/orcl/bdump/orcl2_j001_942754.trc:
ORA-12012: error on auto execute of job 527
ORA-04031: unable to allocate 4256 bytes of shared memory ("shared pool","unknown object","sga heap(2,0)","obj stat memor")
ORA-06512: at "PERFSTAT.STATSPACK", line 2479
ORA-06512: at "PERFSTAT.STATSPACK", line 91
ORA-06512: at line 1
There are 354 memory allocation errors for object-level stat
in the last 15 minutes
There are 653 memory allocation errors for object-level stat
in the last 15 minutes
Mon Apr 30 02:07:45 2012
Thread 2 advanced to log sequence 71531
Current log# 5 seq# 71531 mem# 0: /dev/rlv_redo22_128m
Mon Apr 30 02:07:45 2012
ARC0: Evaluating archive log 4 thread 2 sequence 71530
ARC0: Beginning to archive log 4 thread 2 sequence 71530
Creating archive destination LOG_ARCHIVE_DEST_1: '/archive2/2_71530.dbf'
ARC0: Completed archiving log 4 thread 2 sequence 71530
There are 41 memory allocation errors for object-level stat
in the last 15 minutes

ORA-4031錯誤比較常見，簡單的說就是記憶體不足所致。從上面的錯誤資訊看，記憶體不足發生在共享池上。而Memory allocation errors同樣是共享池空間不足的表現，可以參考文章Memory Allocation Errors For Object-Level Stat Appearing in the Alert Log File [ID 757895.1]。

針對這個問題，可以透過設定隱含引數_OBJECT_STATISTICS=FALSE來禁用物件級統計資訊，但是最徹底的方法還是增加共享池空間。