how to speed up decompress process ?

[vas bolpali]

Hello,
I am trying to decompress( to the same directory) a file dc.dmp.Z
it is taking long time.
any suggestions to speedup .thnx in advance.

here is my case.
$compress -d dc.dmp.Z
dc.dmp already exists; do you wish to overwrite dc.dmp (y or n)? y
-- here is taking long time.

[Uday_S_Ankolekar]

hi,

This may sound silly..

Did you try uncompress instead compress -d

Or if the file was compressed in some other format like gunzip then using gunzip option to de-compress would be better.
How big is the file..??

Good Luck

-USA...

[harry d brown jr]

Have you tried to remove the previous file before the decompress? Also, have you looked into using gzip (from gnu)??

[Alan Riggs]

I assume this is a large file. Compress/decompress are CPU intensive processes. You can speed it up by adjusting the nice value (nice, renice). Be aware that this can negatively impact CPU access for all other processes.

[Santosh Nair_1 · Accepted solution]

Looks like you're dealing with an Oracle dump file(?) These files tend to be fairly large. Rather than uncompressing the file and then importing the file, how about using a pipe to decompress and import the file at the same time? Not really sure if you will save any time doing it this way, but you'll definitely save space.

To do this, first create a pipe file:

mkfifo {PIPE FILE}

then run gzip -d on the pipe (gzip can handle both .gz and .Z files natively)

gzip -dc dc.dmp.Z > {PIPE FILE} &

then start your import

imp file={PIPE FILE} other options.

This will uncompress the file into the pipe where the import utility is waiting to receive the file.

-Santosh