Well, a simple method to import(export) directly to(from) compressed files using pipes. Its for Unix based systems only, as I am not aware of any pipe type functionality in Windows. The biggest advantage is that you can save lots of space as uncompressing a file makes it almost 5 times or more. (Suppose you are uncompressing a file of 20 GB, it will make 100 GB) As a newbie I faced this problem, so thought about writing a post.
Lets talk about export first. The method used is that create a pipe, write to a pipe(ie the file in exp command is the pipe we created), side by side read the contents of pipe, compress (in the background) and redirect to a file. Here is the script that achieves this:
export ORACLE_SID=MYDB rm -f ?/myexport.pipe mkfifo ?/myexport.pipe cat ?/myexport.pipe |compress > ?/myexport.dmp.Z &amp; sleep 5 exp file=?/myexport.pipe full=Y log=myexport.log
Same way for import, we create a pipe, zcat from the dmp.Z file, redirect it to the pipe and then read from pipe:
export ORACLE_SID=MYDB rm -f ?/myimport.pipe mkfifo ?/myimport.pipe zcat ?/myexport.dmp.Z > ?/myimport.pipe &amp; sleep 5 imp file=myimport.pipe full=Y show=Y log=?/myimport.log
In case there is any issue with the script, do let me know 🙂
Update: If you are on Wintel, you can directly use a compressed folder as an export target. No need to create a pipe as the file system will automatically do it for you. ( Thanks Noons for the tip)
If you are using gunzip:
export ORACLE_SID=MYDB rm -f exp.pipe mknod exp.pipe gzip < exp.pipe > T1.dmp.gz &amp; exp file=exp.pipe full=Y log=myexport.log
export ORACLE_SID=MYDB rm -f imp.pipe mknod imp.pipe gzip < T1.dmp.gz > imp.pipe &amp; imp file=imp.pipe full=Y log=myimport.log
Update: I came across an article that discusses few ways to achieve the same on Windows. Check it here.