recovery when tablespace is with nologging option [message #158028] |
Wed, 08 February 2006 02:07 |
kinjal
Messages: 124 Registered: June 2001
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Senior Member |
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Hello,
I have few question related to redo entries.
If my tablespace is created with nologging option then will I be able to recover the data after some crash?
And whethere I can create any table with logging option in tablespace with nologgin option?
Now if I am creating some table and dropping it, will this be recorded to as redo entry?
If DDLs are not recorded as redo then how can we recover the database?
can anyone please explain this?
Kinjal
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Re: recovery when tablespace is with nologging option [message #158077 is a reply to message #158028] |
Wed, 08 February 2006 07:21 |
orausern
Messages: 826 Registered: December 2005
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Senior Member |
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first , WHICH OPERATIONS are affected by nologging clause, for this see:
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/clauses6a.htm#999783
Now:
1) If my tablespace is created with nologging option then will I be able to recover the data after some crash?
-No certain data you may not. e.g. if you create a table like create table a as select * from b nologging; then you will NOT be able to recover table a.
but if u created another table b like
create table b(b1 date); then you will be able to recover the table.
so all operations included in the link above will not be recovered after a crash..so watch out.. you may keep an export back up to you help you out..
2) whethere I can create any table with logging option in tablespace with nologgin option?
Yes you can. AND that logging option overrides the nologging attribute of the tablespace.
(http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/statements_74a.htm#SQLRF01403)
3) Now if I am creating some table and dropping it, will this be recorded to as redo entry?
-it depends how you create it. as said above in point 1.
4) If DDLs are not recorded as redo then how can we recover the database?
keep a export backup also.
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