Re: Building app around Flashback Versions Query

<mimmo.briganti_at_route1.com> wrote in message news:1133462411.054541.98940_at_f14g2000cwb.googlegroups.com...
> Volumes are low and the same record does not get changed very often --
> it's a small database, about 1 gb right now. I don't see it ever
> getting really big. If I enable block change tracking, incremental
> backups should be pretty fast if the undo tablespace gets huge. Thanks
> for your comments.
>
> Mimmo
>

Read consistency works at the block level - which includes index blocks. You don't have to change a record often to end up doing a lot of work getting a read-consistent copy of that record, you only have to change the rows in the same block, or the rows in the index block(s) which are going to help you identify that block.

Incremental backups can be pretty fast - especially if the rate of data change is low - but if you only take incremental backups, how long will a recovery take after six and a half years; so how often are you going to take a full backup to keep recovery time to a reasonable level.

This is a case of the technology making it look simple on paper, but not necessarily being realistic when you try to work out how to use it to meet your actual requirements. Make sure you do the arithmetic up front.

-- 
Regards

Jonathan Lewis

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