Re: db_block_checksum, db_block_checking, dbverify

Don't touch db_block_checksum with a barge pole. It cripples performance, because there's a checksum calculation done on both reads and writes. The 'checkING' version only does it on writes, so the performance impact is negligable.

'CheckSUM' was available in earlier versions, and the advice is only switch it on when Oracle Support tells you to. 'CheckING' was introduced in 8i.

Nice to have two completely different parameters, with wildly different impacts, called by such similar names, I always think!!

Regards
HJR "Gina Dijkhuis" <l.d.dijkhuis_at_ifa.agro.nl> wrote in message news:3b8cdbe3_at_news.wau.nl...
> I'm considering the use of these tools or parameters on an Oracle V8.1.7
> database.
>
> I know that DB_BLOCK_CHECKING is enabled by default on the SYSTEM
> tablespace.
>
> Is it necessarily to use both db_block_checksum and db_block_checking (or
> DBVerify)?
>
> Is the performance decrease measurable?
>
> Does RMAN command VALIDATE BACKUP doing the same as DBVerify?
>
> Thanks,
>
> Gina
>
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>
>
>
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Received on Wed Aug 29 2001 - 15:25:00 CDT