Re: Estimate the Size of an Full Database Export

On HP/UX we have been estimating with an average of 4:1 compression. Only a few tables get worse ratios and many get much better.

Big Al

Billy Verreynne wrote:
>
> Michael Kroh <michael.kroh_at_basf-ag.de> wrote:
>
> >Has anyone a script to estimate the size if a full database export.
> >I need this the check the disk before the export runs.
>
> Auto compress the export (I assume your on Unix).
>
> Something like:
> mkfifo -p pipe.dmp
> compress < pipe.dmp > database.dmp &
> exp userid=sys/password file=pipe.dmp full=y log=export.log
>
> First command above create a FIFO pipe. Second command starts to run
> the compressor in the background, reading from the pipe and writing
> the resultant compressed data into a binary file. The last command
> starts up the exporter and dumps the database down the pipe.
>
> As for determing the size.. guess work will have to do as it depends
> on how well the data can compress. At worse, the export size will be
> the same size as the database, minus of course rollback and temp
> segments. Do a select from dba_data_files, select only the data files
> (exclude the files assigned to the temp and rollback tablespaces) and
> sum the bytes. This should give you a very rough total to play around
> with.
>
> If you need to this on HPUX, give me a shout via private e-mail and I
> can send you my export and import scripts I've got that does
> loading/unloading via pipes to/from compressed files.
>
> Billy
Received on Fri May 26 2000 - 00:00:00 CDT