游标是 SQL 的一个内存工作区，由系统或用户以变量的形式定义。游标的作用就是
用于临时存储从数据库中提取的数据块。在某些情况下，需要把数据从存放在磁盘的表
中调到计算机内存中进行处理，最后将处理结果显示出来或最终写回数据库。这样数据
处理的速度才会提高，否则频繁的磁盘数据交换会降低效率。
游标有两种类型：显式游标和隐式游标，在前述程序中用到的 SELECT…INTO…查询
语句，一次只能从数据库中提取一行数据，对于这种形式的查询和 DML 操作，系统都会
使用一个隐式游标。但是如果要提取多行数据，就要由程序员定义一个显式游标，并通
过与游标有关的语句进行处理。显式游标对应一个返回结果为多行多列的 SELECT 语句。
游标一旦打开，数据就从数据库中传送到游标变量中，然后应用程序再从游标变量
中分解出需要的数据，并进行处理。
MMON和MMNL：在Oracle10g中，有两个后台进程是新增的，
在Oracle不同的文档中，对这两个进程的解释存在歧义。
MMON 应该是 Memory Monitor 的缩写，但是在有的文档中被记录为Manageability Monitor ，这应当是10g早期版本中的称呼，只不过后来发生了变更。
这个进程的主要作用如下：
The memory monitor (MMON) process was introduced in 10g and is associated with the Automatic Workload Repository new features used for automatic problem detection and self-tuning. MMON writes out the required statistics for AWR on a scheduled basis.
另外一个进程是 MMNL ，是 Memory Monitor Light (MMNL) 的缩写，在部分文档中记录为 Manageability Monitor Light .
这个进程的作用如下：
The Memory Monitor Light (MMNL) process is a new process in 10g which works with the Automatic Workload Repository new features (AWR) to write out full statistics buffers to disk as needed.

orcl_mmon_3540.trc
error 1000 happened during job cache initialization
*** 2013-02-21 12:09:27.890
error 1000 happened during job cache initialization
*** 2013-02-21 12:09:51.906
*** KEWUXS - encountered error: (ORA-00604: error occurred at recursive SQL level 2
ORA-01000: maximum open cursors exceeded
) 
*** KEWFADM: Error=13515 encountered by Auto DBFUS Main.
*** KEWUXS - encountered error: (ORA-00604: error occurred at recursive SQL level 2
ORA-01000: maximum open cursors exceeded
) 
*** KEWFACM: Error=13515 encountered by Auto CPU Usage Main.
*** KEWUXS - encountered error: (ORA-00604: error occurred at recursive SQL level 2
ORA-01000: maximum open cursors exceeded
) 
看下游标链接数、最大连接数  
SQL>  show parameter open_cursors;   -->游标最大链接数

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------
open_cursors                         integer     50
SQL> select count(*) from v$open_cursor; -->游标链接数

  COUNT(*)
----------
       207
SQL> alter system set open_cursors=1000 scope=both; -->修改ORACLE最大游标数
系统已更改。
SQL> show parameter open_cursors;
NAME TYPE   VALUE
------------------------------------
open_cursors integer 1000

Error 0 in kwqmnpartition-update_aqs_instance, aborting txn
ORA-0 encountered when generating server alert SMG-3503
ORA-1000 encountered when generating server alert SMG-3503

再看alert_oral.log还是每十分钟报错一遍
Thu Feb 21 14:33:08 2013
ALTER SYSTEM SET open_cursors=1000 SCOPE=BOTH;
Thu Feb 21 14:40:12 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 14:50:13 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 15:00:13 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 15:10:14 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 15:20:14 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 15:30:15 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 15:40:15 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 15:50:16 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 16:00:17 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 16:10:18 2013
ORA-1000 encountered when generating server alert SMG-3000
Thu Feb 21 16:14:10 2013
Starting background process EMN0
EMN0 started with pid=23, OS id=5820
Thu Feb 21 16:14:10 2013
Shutting down instance: further logons disabled
Thu Feb 21 16:14:10 2013
Stopping background process QMNC
Thu Feb 21 16:14:11 2013
Stopping background process CJQ0
Thu Feb 21 16:14:12 2013
Stopping background process MMNL
Thu Feb 21 16:14:13 2013
Stopping background process MMON
Thu Feb 21 16:14:14 2013
Shutting down instance (immediate)
License high water mark = 7
Thu Feb 21 16:14:21 2013
ALTER DATABASE CLOSE NORMAL
Thu Feb 21 16:14:21 2013
SMON: disabling tx recovery
SMON: disabling cache recovery
Thu Feb 21 16:14:22 2013
Shutting down archive processes
Archiving is disabled
Thu Feb 21 16:14:27 2013
ARCH shutting down
ARC1: Archival stopped
Thu Feb 21 16:14:32 2013
ARCH shutting down
ARC0: Archival stopped
Thu Feb 21 16:14:33 2013
Thread 1 closed at log sequence 18
Successful close of redo thread 1
Thu Feb 21 16:14:34 2013
Completed: ALTER DATABASE CLOSE NORMAL
Thu Feb 21 16:14:34 2013
ALTER DATABASE DISMOUNT
Completed: ALTER DATABASE DISMOUNT
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
Archive process shutdown avoided: 0 active
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
Archive process shutdown avoided: 0 active
Thu Feb 21 16:15:18 2013
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Picked latch-free SCN scheme 2
Using LOG_ARCHIVE_DEST_10 parameter default value as USE_DB_RECOVERY_FILE_DEST
Autotune of undo retention is turned on.
IMODE=BR
ILAT =10
LICENSE_MAX_USERS = 0
SYS auditing is disabled
ksdpec: called for event 13740 prior to event group initialization
Starting up ORACLE RDBMS Version: 10.2.0.1.0.
System parameters with non-default values:
  __shared_pool_size       = 75497472
  shared_pool_size         = 75497472
  __large_pool_size        = 4194304
  __java_pool_size         = 4194304
  __streams_pool_size      = 0
  sga_target               = 285212672
  control_files            = E:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\CTLF01.CTL
  __db_cache_size          = 192937984
  compatible               = 10.2.0.1.0
  db_recovery_file_dest    = E:\oracle\product\10.2.0\flash_recovery_area
  db_recovery_file_dest_size= 2147483648
  undo_management          = AUTO
  undo_tablespace          = UNDOTBS1
  audit_file_dest          = E:\ORACLE\PRODUCT\10.2.0\ADMIN\ORCL\ADUMP
  background_dump_dest     = E:\ORACLE\PRODUCT\10.2.0\ADMIN\ORCL\BDUMP
  user_dump_dest           = E:\ORACLE\PRODUCT\10.2.0\ADMIN\ORCL\UDUMP
  core_dump_dest           = E:\ORACLE\PRODUCT\10.2.0\ADMIN\ORCL\CDUMP
  db_name                  = orcl
  open_cursors             = 1000
PMON started with pid=2, OS id=8108
PSP0 started with pid=3, OS id=7060
MMAN started with pid=4, OS id=5072
DBW0 started with pid=5, OS id=3380
LGWR started with pid=6, OS id=6356
CKPT started with pid=7, OS id=2100
SMON started with pid=8, OS id=5704
RECO started with pid=9, OS id=4716
MMON started with pid=10, OS id=3932
MMNL started with pid=11, OS id=6604
Thu Feb 21 16:15:18 2013
ALTER DATABASE   MOUNT
Thu Feb 21 16:15:23 2013
Setting recovery target incarnation to 1
Thu Feb 21 16:15:23 2013
Successful mount of redo thread 1, with mount id 1335725718
Thu Feb 21 16:15:23 2013
Database mounted in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
Thu Feb 21 16:15:23 2013
ALTER DATABASE OPEN
Thu Feb 21 16:15:23 2013
LGWR: STARTING ARCH PROCESSES
ARC0 started with pid=13, OS id=3720
Thu Feb 21 16:15:23 2013
ARC0: Archival started
ARC1: Archival started
LGWR: STARTING ARCH PROCESSES COMPLETE
ARC1 started with pid=14, OS id=6468
Thu Feb 21 16:15:23 2013
Thread 1 opened at log sequence 18
  Current log# 1 seq# 18 mem# 0: E:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\REDO01.LOG
Successful open of redo thread 1
Thu Feb 21 16:15:23 2013
MTTR advisory is disabled because FAST_START_MTTR_TARGET is not set
 -->
Thu Feb 21 16:15:23 2013
ARC0: STARTING ARCH PROCESSES
Thu Feb 21 16:15:23 2013
ARC1: Becoming the 'no FAL' ARCH
ARC1: Becoming the 'no SRL' ARCH
Thu Feb 21 16:15:23 2013
SMON: enabling cache recovery
Thu Feb 21 16:15:23 2013
ARC2: Archival started
ARC2 started with pid=15, OS id=4020
Thu Feb 21 16:15:23 2013
ARC0: STARTING ARCH PROCESSES COMPLETE
ARC0: Becoming the heartbeat ARCH
Thu Feb 21 16:15:25 2013
Successfully onlined Undo Tablespace 1.
Thu Feb 21 16:15:25 2013
SMON: enabling tx recovery
Thu Feb 21 16:15:25 2013
*********************************************************************
WARNING: The following temporary tablespaces contain no files.
         This condition can occur when a backup controlfile has
         been restored.  It may be necessary to add files to these
         tablespaces.  That can be done using the SQL statement:
 
         ALTER TABLESPACE ADD TEMPFILE
 
         Alternatively, if these temporary tablespaces are no longer
         needed, then they can be dropped.
           Empty temporary tablespace: TEMP  -->此告警虽然对数据库没啥大影响，但是生产还是要有tempfile的
*********************************************************************
Database Characterset is ZHS16GBK
replication_dependency_tracking turned off (no async multimaster replication found)
Starting background process QMNC
QMNC started with pid=16, OS id=5944
Thu Feb 21 16:15:29 2013
Completed: ALTER DATABASE OPEN
Thu Feb 21 16:15:30 2013
db_recovery_file_dest_size of 2048 MB is 8.33% used. This is a
user-specified limit on the amount of space that will be used by this
database for recovery-related files, and does not reflect the amount of
space available in the underlying filesystem or ASM diskgroup.
Thu Feb 21 16:15:32 2013
Starting background process CJQ0
CJQ0 started with pid=19, OS id=7188
Thu Feb 21 16:21:23 2013
Shutting down archive processes
Thu Feb 21 16:21:28 2013
到这里都一切正常  改完之后没有在报 ORA-01000: maximum open cursors exceeded错
ARCH shutting down
ARC2: Archival stopped
Thu Feb 21 22:00:14 2013
Errors in file e:\oracle\product\10.2.0\admin\orcl\bdump\orcl_j001_5560.trc:
ORA-25153: Temporary Tablespace is Empty

Thu Feb 21 22:00:14 2013
GATHER_STATS_JOB encountered errors.  Check the trace file.
Thu Feb 21 22:00:14 2013
Errors in file e:\oracle\product\10.2.0\admin\orcl\bdump\orcl_j001_5560.trc:
ORA-25153: Temporary Tablespace is Empty

Thu Feb 21 22:00:32 2013
Errors in file e:\oracle\product\10.2.0\admin\orcl\bdump\orcl_j001_5560.trc:
ORA-25153: Temporary Tablespace is Empty
的解决：
表空间存在，但数据文件不在。物理文件确实也是没有的。
先查看temp数据文件
SQL> select * from v$tempfile;
no rows selected
temp表空间可以找到。
SQL> select tablespace_name from dba_tablespaces where tablespace_name like ‘TEMP’;
TABLESPACE_NAME
——————————
TEMP
尝试添加个临时文件。
SQL> alter tablespace temp add tempfile ‘F:\ORADATA\RBCDNOZ\TEMP01.dbf’ size 10M;
Tablespace altered
SQL> select name from v$tempfile;
NAME
——————————————————————————–
F:\ORADATA\RBCDNOZ\TEMP01.DBF
问题解决。