Wednesday, August 13, 2014

Materialized view Last refresh times

The LAST_REFRESH_DATE column of the DBA_MVIEWS or the LAST_REFRESH column of the DBA_MVIEW_REFRESH_TIMES indicates the start refresh time. But what if we’d like to find out how long the refresh of the materialized view really takes. Well, we can query the DBA_MVIEW_ANALYSIS.
For Complete Refresh, the refresh duration will be in the FULLREFRESHTIM column of the DBA_MVIEW_ANALYSIS. For Fast Refresh duration, it will be in the INCREFRESHTIM column.
Both values are in seconds.
SELECT mview_name, last_refresh_date, fullrefreshtim, increfreshtim
FROM dba_mview_analysis
WHERE owner='JOHN';

MVIEW_NAME               LAST_REFRESH_DATE      FULLREFRESHTIM INCREFRESHTIM
------------------------ ---------------------- -------------- -------------
MV_CHANGE_HISTORY        07-JAN-13 04.36.58 PM               0            36
MV_ITEM_HISTORY          07-JAN-13 04.36.58 PM               0             9
This shows that the recent refresh of the MV_CHANGE_HISTORY and MV_ITEM_HISTORY are the fast refreshes for 36 and 9 seconds respectively.
Put in one query to calculate and display the end time.
SELECT 
   mview_name,
   last_refresh_date "START_TIME",
   CASE
      WHEN fullrefreshtim <> 0 THEN
         LAST_REFRESH_DATE + fullrefreshtim/60/60/24
      WHEN increfreshtim <> 0 THEN
         LAST_REFRESH_DATE + increfreshtim/60/60/24
      ELSE
         LAST_REFRESH_DATE
   END "END_TIME",
   fullrefreshtim,
   increfreshtim
FROM all_mview_analysis
WHERE owner='JOHN';

MVIEW_NAME              START_TIME             END_TIME               FULLREFRESHTIM INCREFRESHTIM
----------------------- ---------------------- ---------------------- -------------- -------------
MV_CHANGE_HISTORY       07-JAN-13 04.36.58 PM  07-JAN-13 04.37.34 PM               0            36
MV_ITEM_HISTORY         07-JAN-13 04.36.58 PM  07-JAN-13 04.37.07 PM               0             9
Reference: How To Calculate MVIEW Refresh Duration? What Does DBA_MVIEWS.LAST_REFRESH_DATE and DBA_MVIEW_REFRESH_TIMES.LAST_REFRESH Indicate? [ID 1513554.1]

Some other views:
dba_mviews
dba_mviews_analysis
dba_mviews_logs

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