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Byte to Char storage change impact on Table & caused performance issue.

User536214 - Oracle-OracleJun 11 2013 — edited Jun 11 2013

Hello Team,

i need you help in resolving the performance issue of database (10.2.0.5 on AIX ).

customer claim that his nightly job which is use to take 1 hr to Complet now it is taking 4 hrs to complete.

when we have anylsed diffrent reports We know those 4 facts about this process:

1) Query was not changed.

2) Stats were not changed.

3) Query Plan was not changed.

only change we have come to know on the database is that 24 columns of table has been changed from bytes to char on varchar2 .some of the columns also having index on it.

below are the sample commands used for changing the columns .

ALTER TABLE      test.data        MODIFY (check               VARCHAR2(35   CHAR));

ALTER TABLE      test.data        MODIFY (test_2              VARCHAR2(120   CHAR));

Now cutsomer wants to know will changing the Table  columns from byte to char has any impact ?

what are the impacts of bytes to char on a table ?

Thanks

Manju

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Locked on Jul 9 2013
Added on Jun 11 2013
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