La variable statistics level permet des stocker des statistiques dans certaines vues.
La requête suivante permet de voir quelle vue est impactée, à quel niveau de statistique et si le calcul de la statistique peut être modifié au niveau session
select decode(ACTIVATION_LEVEL,1,'Typical','All') "A Level"
, Name
, decode(SESSION_CHANGEABLE,1,'Ok',' -') "Modif"
, decode(SESSION_STATUS,1,'On',' -') "Sess"
, decode(SYSTEM_STATUS,1,'On',' -') "Sys"
, VIEW_NAME
from x$prmsltyx
order by ACTIVATION_LEVEL
/
En 11gR2 on obtient
A Level NAME Mo Se Sy VIEW_NAME
------- ---------------------------------------------------------------- -- -- -- -------------------------
Typical Buffer Cache Advice - On On V$DB_CACHE_ADVICE
Typical V$IOSTAT_* statistics - On On
Typical Timed Statistics Ok On On
Typical MTTR Advice - On On V$MTTR_TARGET_ADVICE
Typical Adaptive Thresholds Enabled - On On
Typical Segment Level Statistics - On On V$SEGSTAT
Typical PGA Advice - On On V$PGA_TARGET_ADVICE
Typical Shared Pool Advice - On On V$SHARED_POOL_ADVICE
Typical Modification Monitoring - On On
Typical Longops Statistics - On On V$SESSION_LONGOPS
Typical Bind Data Capture - On On V$SQL_BIND_CAPTURE
Typical Ultrafast Latch Statistics - On On
Typical Threshold-based Alerts - On On
Typical Global Cache Statistics - On On
Typical Active Session History - On On V$ACTIVE_SESSION_HISTORY
Typical Undo Advisor, Alerts and Fast Ramp up - On On V$UNDOSTAT
Typical Streams Pool Advice - On On V$STREAMS_POOL_ADVICE
Typical Time Model Events Ok On On V$SESS_TIME_MODEL
Typical Plan Execution Sampling Ok On On V$ACTIVE_SESSION_HISTORY
Typical Automated Maintenance Tasks - On On
Typical SQL Monitoring Ok On On V$SQL_MONITORING
All Plan Execution Statistics Ok - - V$SQL_PLAN_STATISTICS
All Timed OS Statistics Ok - -
En 10g on obtient
A Level NAME Mo Se Sy VIEW_NAME
------- ---------------------------------------- -- -- -- ------------------------------
Typical Buffer Cache Advice - On On V$DB_CACHE_ADVICE
Typical Streams Pool Advice - On On V$STREAMS_POOL_ADVICE
Typical Timed Statistics Ok On On
Typical MTTR Advice - On On V$MTTR_TARGET_ADVICE
Typical Undo Advisor, Alerts and Fast Ramp up - On On V$UNDOSTAT
Typical Segment Level Statistics - On On V$SEGSTAT
Typical PGA Advice - On On V$PGA_TARGET_ADVICE
Typical Shared Pool Advice - On On V$SHARED_POOL_ADVICE
Typical Modification Monitoring - On On
Typical Longops Statistics - On On V$SESSION_LONGOPS
Typical Bind Data Capture - On On V$SQL_BIND_CAPTURE
Typical Ultrafast Latch Statistics - On On
Typical Threshold-based Alerts - On On
Typical Global Cache Statistics - On On
Typical Active Session History - On On V$ACTIVE_SESSION_HISTORY
All Plan Execution Statistics Ok - - V$SQL_PLAN_STATISTICS
All Timed OS Statistics Ok - -
En 9i on obtient
A Level NAME Mo Se Sy VIEW_NAME
------- ------------------------------ -- -- -- ------------------------------
Typical Buffer Cache Advice - On On V$DB_CACHE_ADVICE
Typical MTTR Advice - On On V$MTTR_TARGET_ADVICE
Typical Timed Statistics Ok On On
Typical PGA Advice - On On V$PGA_TARGET_ADVICE
Typical Shared Pool Advice - On On V$SHARED_POOL_ADVICE
Typical Segment Level Statistics - On On V$SEGSTAT
All Timed OS Statistics Ok - -
All Plan Execution Statistics Ok - - V$SQL_PLAN_STATISTICS