Re: exp DB -> Binary file size??

On Fri, 20 Aug 2004 21:33:15 +0200, Holger Spangardt <Holger.Spangardt_at_web.de> wrote:

>qazmlp wrote:
>
>Hi,
>
>> The size of the Oracle Database that we have in our Solaris machine
>> is:'N' GB. We want to use 'exp' utility to export this DB into a file.
>> What will be the size of that binary file? Does Oracle provide some
>> specification on this?
>
>select sum(bytes/1024/1024) from user_segments
>where segment_type = 'TABLE';
>
>should give you a good estimation in MB.
>
>Hope this helps,
> Holger

Hi Holger and qazmlp,

That estimate is not reliable for 2 reasons :

1. It does not include e.g. IOT's and LOB-segments => estimate too low.
2. It assumes 100% utilization of the table blocks, which is rarely the case => estimate too high. This is of course not the worst harm.

It's not that simple to estimate the size of an export file, but you can find the worst case by summing the bytes of all segments that are in fact known to be included in the export (incl.Tables, Lobs, IOTs etc, but not regular indexes). The export file will not be larger than this sum, and probably a good deal smaller.

• Kenneth Koenraadt