v$statistics_level in Oracle10g
Oracle9205中v$statistics_level返回8行,10gR2中返回17行。控制了更多的统计信息的收集.
如果设置statistics_level=baisc,竟然连V$SESSION_LONGOPS这个有用的功能就无法使用了,不过微调一些underscored参数,可以选择的enable一些statistics.
#############STATISTICS_LEVEL = BASIC###########
col statistics_name for a30 head "Statistics Name"
col session_status for a10 head "Session|Status"
col system_status for a10 head "System|Status"
col activation_level for a10 head "Activation|Level"
col session_settable for a10 head "Session|Settable"
col STATISTICS_VIEW_NAME for a10 head "view_name"
SQL> SELECT STATISTICS_NAME,
2 SESSION_STATUS,
3 SYSTEM_STATUS,
4 ACTIVATION_LEVEL,
5 SESSION_SETTABLE
6 ,STATISTICS_VIEW_NAME from v$statistics_level order by 1;
Session System Activation Session
Statistics Name Status Status Level Settable view_name
------------------------------ ---------- ---------- ---------- ---------- ------------------------
Active Session History DISABLED DISABLED TYPICAL NO V$ACTIVE_SESSION_HISTORY
Bind Data Capture DISABLED DISABLED TYPICAL NO V$SQL_BIND_CAPTURE
Buffer Cache Advice DISABLED DISABLED TYPICAL NO V$DB_CACHE_ADVICE
Global Cache Statistics DISABLED DISABLED TYPICAL NO
Longops Statistics DISABLED DISABLED TYPICAL NO V$SESSION_LONGOPS
MTTR Advice DISABLED DISABLED TYPICAL NO V$MTTR_TARGET_ADVICE
Modification Monitoring DISABLED DISABLED TYPICAL NO
PGA Advice DISABLED DISABLED TYPICAL NO V$PGA_TARGET_ADVICE
Plan Execution Statistics DISABLED DISABLED ALL YES V$SQL_PLAN_STATISTICS
Segment Level Statistics DISABLED DISABLED TYPICAL NO V$SEGSTAT
Shared Pool Advice DISABLED DISABLED TYPICAL NO V$SHARED_POOL_ADVICE
Streams Pool Advice ENABLED ENABLED TYPICAL NO V$STREAMS_POOL_ADVICE
Threshold-based Alerts DISABLED DISABLED TYPICAL NO
Timed OS Statistics DISABLED DISABLED ALL YES
Timed Statistics ENABLED ENABLED TYPICAL YES
Ultrafast Latch Statistics DISABLED DISABLED TYPICAL NO
Undo Advisor, Alerts and Fast DISABLED DISABLED TYPICAL NO V$UNDOSTAT
Ramp up
17 rows selected.
SQL> show parameters
NAME VALUE
------------------------------ -----
statistics_level basic
timed_os_statistics 0
timed_statistics TRUE
_db_cache_advice_batch_size 128
_db_cache_advice_sample_factor 4
_db_mttr_advice OFF
_kglsim_maxmem_percent 5
_library_cache_advice FALSE
_smm_advice_enabled FALSE
_smm_advice_log_size 0
db_cache_advice OFF
_longops_enabled FALSE
col statistics_name for a30 head "Statistics Name"
col session_status for a10 head "Session|Status"
col system_status for a10 head "System|Status"
col activation_level for a10 head "Activation|Level"
col session_settable for a10 head "Session|Settable"
col STATISTICS_VIEW_NAME for a10 head "view_name"
SQL> SELECT STATISTICS_NAME,
2 SESSION_STATUS,
3 SYSTEM_STATUS,
4 ACTIVATION_LEVEL,
5 SESSION_SETTABLE
6 ,STATISTICS_VIEW_NAME from v$statistics_level order by 1;
Session System Activation Session
Statistics Name Status Status Level Settable view_name
------------------------------ ---------- ---------- ---------- ---------- ------------------------
Active Session History DISABLED DISABLED TYPICAL NO V$ACTIVE_SESSION_HISTORY
Bind Data Capture DISABLED DISABLED TYPICAL NO V$SQL_BIND_CAPTURE
Buffer Cache Advice DISABLED DISABLED TYPICAL NO V$DB_CACHE_ADVICE
Global Cache Statistics DISABLED DISABLED TYPICAL NO
Longops Statistics DISABLED DISABLED TYPICAL NO V$SESSION_LONGOPS
MTTR Advice DISABLED DISABLED TYPICAL NO V$MTTR_TARGET_ADVICE
Modification Monitoring DISABLED DISABLED TYPICAL NO
PGA Advice DISABLED DISABLED TYPICAL NO V$PGA_TARGET_ADVICE
Plan Execution Statistics DISABLED DISABLED ALL YES V$SQL_PLAN_STATISTICS
Segment Level Statistics DISABLED DISABLED TYPICAL NO V$SEGSTAT
Shared Pool Advice DISABLED DISABLED TYPICAL NO V$SHARED_POOL_ADVICE
Streams Pool Advice ENABLED ENABLED TYPICAL NO V$STREAMS_POOL_ADVICE
Threshold-based Alerts DISABLED DISABLED TYPICAL NO
Timed OS Statistics DISABLED DISABLED ALL YES
Timed Statistics ENABLED ENABLED TYPICAL YES
Ultrafast Latch Statistics DISABLED DISABLED TYPICAL NO
Undo Advisor, Alerts and Fast DISABLED DISABLED TYPICAL NO V$UNDOSTAT
Ramp up
17 rows selected.
SQL> show parameters
NAME VALUE
------------------------------ -----
statistics_level basic
timed_os_statistics 0
timed_statistics TRUE
_db_cache_advice_batch_size 128
_db_cache_advice_sample_factor 4
_db_mttr_advice OFF
_kglsim_maxmem_percent 5
_library_cache_advice FALSE
_smm_advice_enabled FALSE
_smm_advice_log_size 0
db_cache_advice OFF
_longops_enabled FALSE



















v$parameter中
name=’statistics_level’的那条记录的’isdefault’字段中
true和false分别代表什么意思?
望回答
See OTN exaplainnation:
http://download.oracle.com/docs/cd/B12037_01/server.101/b10755/dynviews_2012.htm
Setting the STATISTICS_LEVEL parameter to BASIC disables the collection of many of the important
statistics required by Oracle Database features and functionality, including:
- Automatic Workload Repository (AWR) Snapshots
- Automatic Database Diagnostic Monitor (ADDM)
- All server-generated alerts
- Automatic SGA Memory Management
- Automatic optimizer statistics collection
- Object level statistics
- End to End Application Tracing (V$CLIENT_STATS)
- Database time distribution statistics (V$SESS_TIME_MODEL and V$SYS_TIME_MODEL)
- Service level statistics
- Buffer cache advisory
- MTTR advisory
- Shared pool sizing advisory
- Segment level statistics
- PGA Target advisory
- Timed statistics
- Monitoring of statistics