On 5th October 2009, at 7:00AM, we have been reported of a problem which is pertaining to the Forecast for HAL. After through analysis, we found that this has occurred because there was double entry HAL records in the EXPECTED_RATIO. Our next concern was at what time this double entry was done.
Was it done by the Planning Engineers when they did the entry on 4th October in the EXPECTED_RATIO table for the forecast of 5th October or Was it done by the Engineers during the night shift as the problem started after the successful completion of the 1:00AM reading.
To Find out this, we are using the Flashback Query Feature of Oracle.
What is Flashback Query :
Flashback Query provides a simple, powerful and completely non-disruptive mechanism for recovering from human errors. It allows users to view the state of data at a point in time in the past without requiring any structural changes to the database.
Or in Simple Terms
Table data can be queried as it existed at a point in time.
We understood from the users that they were experiencing the problem since 2:00 AM. So, we gave the following Query on the Live Database on 7th October at 14:00hrs.
SQL> SELECT * FROM EXPECTED_RATIO AS OF TIMESTAMP TO_TIMESTAMP('05-OCT-2009 01:15:00','DD-MON-YYYY HH24:MI:SS') WHERE RATIO_DATE>'04-OCT-09'
RATIO_DAT RATIO_TIME AREA_ID RATIO_PERCENTAGE RATIO_SEQ
--------- ---------- ---------- ---------------- ----------
05-OCT-09 00:00 HAL 1.01 1
05-OCT-09 00:00 QSM 1.008 1
05-OCT-09 00:00 RUH .986 1
05-OCT-09 01:00 HAL 1.01948052 1
05-OCT-09 01:00 QSM .99559859 1
05-OCT-09 01:00 RUH 1.00820853 1
05-OCT-09 02:00 HAL .99044586 1
05-OCT-09 02:00 QSM .99734748 1
05-OCT-09 02:00 RUH .99171547 1
05-OCT-09 03:00 HAL .97749196 1
05-OCT-09 03:00 QSM .96631206 1
05-OCT-09 03:00 RUH .97580297 1
05-OCT-09 04:00 HAL .97039474 1
05-OCT-09 04:00 QSM .96422018 1
05-OCT-09 04:00 RUH .97830258 1
05-OCT-09 05:00 HAL .99322034 1
05-OCT-09 05:00 QSM .97240723 1
05-OCT-09 05:00 RUH .96394086 1
05-OCT-09 06:00 HAL .86006826 1
05-OCT-09 06:00 QSM .94129159 1
05-OCT-09 06:00 RUH .93817499 1
05-OCT-09 07:00 HAL .97619048 1
05-OCT-09 07:00 QSM .98960499 1
05-OCT-09 07:00 RUH 1.01351351 1
05-OCT-09 08:00 HAL 1.07723577 1
05-OCT-09 08:00 QSM 1.11239496 1
05-OCT-09 08:00 RUH 1.07209877 1
05-OCT-09 09:00 HAL 1.05660377 1
05-OCT-09 09:00 QSM 1.05288008 1
05-OCT-09 09:00 RUH 1.05419929 1
05-OCT-09 10:00 HAL 1.05714286 1
05-OCT-09 10:00 QSM 1.06457399 1
05-OCT-09 10:00 RUH 1.05913195 1
05-OCT-09 11:00 HAL 1.01013514 1
05-OCT-09 11:00 QSM 1.01179444 1
05-OCT-09 11:00 RUH 1.03492849 1
05-OCT-09 12:00 HAL 1.01003344 1
05-OCT-09 12:00 QSM .97002498 1
05-OCT-09 12:00 RUH .98937018 1
05-OCT-09 13:00 HAL .99668874 1
05-OCT-09 13:00 QSM .98798283 1
05-OCT-09 13:00 RUH 1.00993822 1
05-OCT-09 14:00 HAL 1.05980066 1
05-OCT-09 14:00 QSM 1.04604692 1
05-OCT-09 14:00 RUH 1.01023936 1
05-OCT-09 15:00 HAL 1.02821317 1
05-OCT-09 15:00 QSM 1.02574751 1
05-OCT-09 15:00 RUH 1.01171515 1
05-OCT-09 16:00 HAL .96036585 1
05-OCT-09 16:00 QSM .98218623 1
05-OCT-09 16:00 RUH .97215717 1
05-OCT-09 17:00 HAL .95555556 1
05-OCT-09 17:00 QSM .98598516 1
05-OCT-09 17:00 RUH .9760439 1
05-OCT-09 18:00 HAL .96345515 1
05-OCT-09 18:00 QSM .97073579 1
05-OCT-09 18:00 RUH 1.0076786 1
05-OCT-09 19:00 HAL 1.14137931 1
05-OCT-09 19:00 QSM 1.00861326 1
05-OCT-09 19:00 RUH 1.02054701 1
05-OCT-09 20:00 HAL .96374622 1
05-OCT-09 20:00 QSM .9675491 1
05-OCT-09 20:00 RUH .96773333 1
05-OCT-09 21:00 HAL .98119122 1
05-OCT-09 21:00 QSM .9788173 1
05-OCT-09 21:00 RUH .97451088 1
05-OCT-09 22:00 HAL .99361022 1
05-OCT-09 22:00 QSM .98016231 1
05-OCT-09 22:00 RUH .99773788 1
05-OCT-09 23:00 HAL .96784566 1
05-OCT-09 23:00 QSM .97424103 1
05-OCT-09 23:00 RUH .97775259 1
05-OCT-09 24:00 HAL 1.00996678 1
05-OCT-09 24:00 QSM 1.00849858 1
05-OCT-09 24:00 RUH .98637681 1
75 rows selected.
SQL> SELECT * FROM EXPECTED_RATIO AS OF TIMESTAMP TO_TIMESTAMP('05-OCT-2009 02:15:00','DD-MON-YYYY HH24:MI:SS') WHERE RATIO_DATE>'04-OCT-09'
RATIO_DAT RATIO_TIME AREA_ID RATIO_PERCENTAGE RATIO_SEQ
--------- ---------- ---------- ---------------- ----------
05-OCT-09 00:00 HAL 1.01 1
05-OCT-09 00:00 QSM 1.008 1
05-OCT-09 00:00 RUH .986 1
05-OCT-09 01:00 HAL 1.01948052 1
05-OCT-09 01:00 QSM .99559859 1
05-OCT-09 01:00 RUH 1.00820853 1
05-OCT-09 02:00 HAL .99044586 1
05-OCT-09 02:00 QSM .99734748 1
05-OCT-09 02:00 RUH .99171547 1
05-OCT-09 03:00 HAL .97749196 1
05-OCT-09 03:00 QSM .96631206 1
05-OCT-09 03:00 RUH .97580297 1
05-OCT-09 04:00 HAL .97039474 1
05-OCT-09 04:00 QSM .96422018 1
05-OCT-09 04:00 RUH .97830258 1
05-OCT-09 05:00 HAL .99322034 1
05-OCT-09 05:00 QSM .97240723 1
05-OCT-09 05:00 RUH .96394086 1
05-OCT-09 06:00 HAL .86006826 1
05-OCT-09 06:00 QSM .94129159 1
05-OCT-09 06:00 RUH .93817499 1
05-OCT-09 07:00 HAL .97619048 1
05-OCT-09 07:00 QSM .98960499 1
05-OCT-09 07:00 RUH 1.01351351 1
05-OCT-09 08:00 HAL 1.07723577 1
05-OCT-09 08:00 QSM 1.11239496 1
05-OCT-09 08:00 RUH 1.07209877 1
05-OCT-09 09:00 HAL 1.05660377 1
05-OCT-09 09:00 QSM 1.05288008 1
05-OCT-09 09:00 RUH 1.05419929 1
05-OCT-09 10:00 HAL 1.05714286 1
05-OCT-09 10:00 QSM 1.06457399 1
05-OCT-09 10:00 RUH 1.05913195 1
05-OCT-09 11:00 HAL 1.01013514 1
05-OCT-09 11:00 QSM 1.01179444 1
05-OCT-09 11:00 RUH 1.03492849 1
05-OCT-09 12:00 HAL 1.01003344 1
05-OCT-09 12:00 QSM .97002498 1
05-OCT-09 12:00 RUH .98937018 1
05-OCT-09 13:00 HAL .99668874 1
05-OCT-09 13:00 QSM .98798283 1
05-OCT-09 13:00 RUH 1.00993822 1
05-OCT-09 14:00 HAL 1.05980066 1
05-OCT-09 14:00 QSM 1.04604692 1
05-OCT-09 14:00 RUH 1.01023936 1
05-OCT-09 15:00 HAL 1.02821317 1
05-OCT-09 15:00 QSM 1.02574751 1
05-OCT-09 15:00 RUH 1.01171515 1
05-OCT-09 16:00 HAL .96036585 1
05-OCT-09 16:00 QSM .98218623 1
05-OCT-09 16:00 RUH .97215717 1
05-OCT-09 17:00 HAL .95555556 1
05-OCT-09 17:00 QSM .98598516 1
05-OCT-09 17:00 RUH .9760439 1
05-OCT-09 18:00 HAL .96345515 1
05-OCT-09 18:00 QSM .97073579 1
05-OCT-09 18:00 RUH 1.0076786 1
05-OCT-09 19:00 HAL 1.14137931 1
05-OCT-09 19:00 QSM 1.00861326 1
05-OCT-09 19:00 RUH 1.02054701 1
05-OCT-09 20:00 HAL .96374622 1
05-OCT-09 20:00 QSM .9675491 1
05-OCT-09 20:00 RUH .96773333 1
05-OCT-09 21:00 HAL .98119122 1
05-OCT-09 21:00 QSM .9788173 1
05-OCT-09 21:00 RUH .97451088 1
05-OCT-09 22:00 HAL .99361022 1
05-OCT-09 22:00 QSM .98016231 1
05-OCT-09 22:00 RUH .99773788 1
05-OCT-09 23:00 HAL .96784566 1
05-OCT-09 23:00 QSM .97424103 1
05-OCT-09 23:00 RUH .97775259 1
05-OCT-09 24:00 HAL 1.00996678 1
05-OCT-09 24:00 QSM 1.00849858 1
05-OCT-09 24:00 RUH .98637681 1
05-OCT-09 01:00 HAL 0 202975
05-OCT-09 02:00 HAL 0 202976
05-OCT-09 03:00 HAL 0 202977
05-OCT-09 04:00 HAL 0 202978
05-OCT-09 05:00 HAL 0 202979
05-OCT-09 06:00 HAL 0 202980
05-OCT-09 07:00 HAL 0 202981
05-OCT-09 08:00 HAL 0 202982
05-OCT-09 09:00 HAL 0 202983
05-OCT-09 10:00 HAL 0 202984
05-OCT-09 11:00 HAL 0 202985
05-OCT-09 12:00 HAL 0 202986
05-OCT-09 13:00 HAL 0 202987
05-OCT-09 14:00 HAL 0 202988
05-OCT-09 15:00 HAL 0 202989
05-OCT-09 16:00 HAL 0 202990
05-OCT-09 17:00 HAL 0 202991
05-OCT-09 18:00 HAL 0 202992
05-OCT-09 19:00 HAL 0 202993
05-OCT-09 20:00 HAL 0 202994
05-OCT-09 21:00 HAL 0 202995
05-OCT-09 22:00 HAL 0 202996
05-OCT-09 23:00 HAL 0 202997
05-OCT-09 24:00 HAL 0 202998
99 rows selected.
As can be seen from above, the changes did happen during the Night Shift after 1:00 AM.
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