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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Export sizing
O'Neill, Sean wrote:
>
> Is there some way to calculate or make a realistic guestimate as to what
> size an Export dump file will be for a given schema or indeed a whole
> database. I've not come across anything on this topic before. If result is
> dependant on O.S. I'm particularily interested in NT/W2K O.S.
>
> Sean :)
>
> Rookie Data Base Administrator
> [0%] OCP Oracle8i DBA
> [0%] OCP Oracle9i DBA
> -------------------------------- ------------
> Organon (Ireland) Ltd.
> E-mail: sean.oneill_at_organon.ie [subscribed: Digest Mode]
>
Sean,
It is more guesstimate than calculation. Basically, your export file
contains CREATE statements and data in the internal Oracle format. You
can dismiss CREATE TABLE, CREATE INDEX statements and the like (tiny).
For data, summing up used blocks as computed by the statistics (failing
that, allocated blocks which will give you at least an upper bound) is
reasonably close. In fact it's a little above reality because of block
overhead, but it in a way balances CREATE statements we have ignored.
Besides data (no need to add any other type of block, indexes are
recreated during the import, and so are rollback segments), what takes
up a lot of space in a .dmp file is the source code for stored objects.
You can easily compute how much is needed fo packages, functions and
procedures from DBA_SOURCE. For triggers and views (stored as LONG
values), there is a column in respectively DBA_TRIGGERS and DBA_VIEWS (I
think. Otherwise dig into sys.trig$ and sys.view$) which stores the
actual length.
As a rule of thumb, a .dmp is about 30% of the database volume.
HTH,
Stephane Faroult
Oriole Corporation
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Stephane Faroult INET: sfaroult_at_oriolecorp.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Tue Jun 12 2001 - 04:29:13 CDT
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