Re: Hot Backups

In article <CH20tM.AAL_at_freenet.carleton.ca>, Doug Harris <ah513_at_Freenet.carleton.ca> wrote:
>
>In a previous article, cds016_at_isadmin1.comm.mot.com (David Schmitt) says:
>
>> When running exports...
>> You can keep the database up, but then you sacrifice
>> logical consistency _between_ tables (logical consistency is maintained
>> _within_ a table, however).
>
> The Oracle7 export has a new option CONSISTENT=Y which provides logical
>consistency between tables. It is unfortunately incompatible with
>incremental exports. exp is essentially performing a SET TRANSACTION
>READ ONLY at the beginning of the export.

Interesting. Does this mean that (1) rollback segments extents can't be freed/reused until the export completes [restrictive], (2) exports fail if a page is out of date and the rollback entry is no longer available [just as can happen in V6 with long transactions], or (3) exports somehow include rollback segment pages in their output [but what about importing on other architectures?]

From what you say about SET TRANSACTION READ ONLY, it sounds like (2) is what they are doing, which would make this ineffective for large databases, right?

-- 
David Schmitt, Manager, Technical Services	Voice:	(708)538-4699
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