Re: export with compress=Y

Bass Chorng wrote:
>
> I have a question about export with compress=Y.
>
> If I have a table using 2 extents with the 2nd
> extent 10% full. Now if I export this table with
> compress=Y and drop the table and import it back
> again, what's my new initial extent size ?
>
> Would it be merging 2 extents into one, still carrying
> that 90% free space, or it would automatically
> size it down to fit the actual data ?
>
> Appreciate any feedback on this.
>
> -Bass Chorng
> DBA
> Octel communications.

Bass,

It sure would carry that 90 percent free space and may be even more because an import also solves any fragmentation and wasted space issues within the table. Compress_extents simply means: calculate the sum of all segments of that object current in use and make that the new INITIAL extent. The first next extent is set to 10 percent of the new initial extent size.
There is a different solution:
compute statistics on the tables involved. This will give accurate values in the dictionary regarding the number of blocks in use. Export the tables normally, drop the old table and precreate the table wih the new values before importing. I know this sounds very tedious, but as far as I know this is the only way to do it.

Hope this helps,

Sybrand Bakker
Senior IS Analyst
Bentley Systems Europe
Sybrand.Bakker_at_Bentley.nl Received on Thu Feb 15 1996 - 00:00:00 CET