How to verify whether TIMED_STATISTICS changed between the oracle AWR database snapshots ?

To verify whether TIMED_STATISTICS changed between the snapshots used in your AWR Diff report, you can check the historical parameter values stored in AWR.

Method 1: Check Parameter History from AWR

SELECT s.snap_id,

s.instance_number,

TO_CHAR(s.begin_interval_time,'DD-MON-YYYY HH24:MI') begin_time,

p.value

FROM dba_hist_parameter p,

dba_hist_snapshot s

WHERE p.snap_id = s.snap_id

AND p.dbid = s.dbid

AND p.instance_number = s.instance_number

AND p.parameter_name = 'timed_statistics'

ORDER BY s.snap_id;

Look for changes in the VALUE column (TRUE/FALSE).

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Method 2: Check Only the Snapshots Used in the Report

If your report compared snapshots 100-101 with 200-201:

SELECT snap_id,

value

FROM dba_hist_parameter

WHERE parameter_name = 'timed_statistics'

AND snap_id IN (100,101,200,201)

ORDER BY snap_id;

Example output:

SNAP_ID VALUE

------- -----

100 FALSE

101 FALSE

200 TRUE

201 TRUE

This would explain the warning.

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Method 3: Find Exactly When the Value Changed

SELECT snap_id,

value,

LAG(value) OVER (ORDER BY snap_id) prev_value

FROM dba_hist_parameter

WHERE parameter_name = 'timed_statistics'

ORDER BY snap_id;

Or show only the change point:

WITH p AS

(

SELECT snap_id,

value,

LAG(value) OVER (ORDER BY snap_id) prev_value

FROM dba_hist_parameter

WHERE parameter_name = 'timed_statistics'

)

SELECT *

FROM p

WHERE value <> prev_value;

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Method 4: Check Database Restart Between Snapshots

Sometimes the warning appears because the database was restarted and initialization parameters changed.

SELECT snap_id,

startup_time,

begin_interval_time

FROM dba_hist_snapshot

ORDER BY snap_id;

Look for a change in STARTUP_TIME between your snapshot ranges.

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RAC Environment

If this is RAC, check all instances:

SELECT snap_id,

instance_number,

value

FROM dba_hist_parameter

WHERE parameter_name = 'timed_statistics'

ORDER BY instance_number, snap_id;

A change on even one instance can trigger the warning.