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Tom Kyte

Thanks for the question, Anthony.

Asked: May 18, 2000 - 9:36 am UTC

Last updated: September 20, 2004 - 8:59 am UTC

Version: 8.1.5

Viewed 1000+ times

You Asked

Hi ,
I try to increase data block size in oracle version 8.1.5. But when I finished modify the parameter of data block size in init.ora and restart the database , an error occured "mismatch block size in control file ".
Could you tell me how to modify the block size properly ? And how to do it ?



and Tom said...

You cannot modify the data block size after a database is created. You can only create a new database with the correct block size, export the old database and do a full import into the new database.

Changing the block size would require the entire database to be rewritten block by block -- each index would have to be rebuilt as well (since the rowids they contain would be invalid). Given that -- the only way to do a block size change is a total rebuild from scratch.

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Comments

How to change block size correctly

vijay, July 17, 2004 - 2:20 am UTC

It was really a useful answer for me

Tom Kyte
July 17, 2004 - 2:40 pm UTC

should mention multi-block size databases are feasible in 9i -- however, they would not be a recommended configuration -- there were implemted to permit the transporting of data from a database with a Nk blocksize to an Mk blocksize for extract/transform/load processing.

How is multi-block size handled in RMAN ?

Anil Pant, September 20, 2004 - 8:43 am UTC

The book says "each file in a backup set must have same oracle block size". Then how is multi-block size handled in RMAN ?

Tom Kyte
September 20, 2004 - 8:59 am UTC

which "book", pointers please (otn.oracle.com -> documentation, give a URL like I do)

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