Hi gurus,

My Unix 2.5.1 server has a file size limitation of 2Gbytes, due to the 32 bit file system. I have a large database that needs exporting, so I have split it into schema level. Problem is, there is a schema with a table in there that produce exp dmp larger than 2Gbytes, so either way I am strapped by this file size limit.

I have tried using background compress while exporting the file, and it works. I am able to send the dmp file straight to a compress pipe, and the final output is a *.Z file. The following is the script that I used:

mknod /tmp/exp_pipe p
compress < /tmp/exp_pipe > export.dmp.Z &
exp file=/tmp/exp_pipe userid=system/manager full=y etc. etc.

My question is as follows:
I split the large database into three seperate exp jobs, and I use the above background compress method on all three segments. The following is the script:

mknod /tmp/exp_pipe p
compress < /tmp/exp_pipe > export1.dmp.Z &
exp file=/tmp/exp_pipe userid=system/manager owner=A full=y etc.
compress < /tmp/exp_pipe > export2.dmp.Z &
exp file=/tmp/exp_pipe userid=system/manager owner=B,C full=y etc.
compress < /tmp/exp_pipe > export3.dmp.Z &
exp file=/tmp/exp_pipe userid=system/manager owner=D,E,F full=y etc.

When I run this script, it seems to be working, but when I go to the tmp directory to look at the *.dmp.Z files as they come out, I notice that ALL THREE export*.dmp.Z files are growing simultaneously. Take a look at the following ls -lta results:

#ls -lta
-rw-r--r-- 1 oracle dba 23240704 Jul 21 11:06 export1.dmp.Z
-rw-r--r-- 1 oracle dba 23666688 Jul 21 11:06 export2.dmp.Z
-rw-r--r-- 1 oracle dba 23109632 Jul 21 11:06 export3.dmp.Z
#ls -lta
-rw-r--r-- 1 oracle dba 44072960 Jul 21 11:15 export1.dmp.Z
-rw-r--r-- 1 oracle dba 43769856 Jul 21 11:15 export2.dmp.Z
-rw-r--r-- 1 oracle dba 42811392 Jul 21 11:15 export3.dmp.Z
#ls -lta
-rw-r--r-- 1 oracle dba 47097739 Jul 21 11:17 export1.dmp.Z
-rw-r--r-- 1 oracle dba 46726417 Jul 21 11:17 export2.dmp.Z
-rw-r--r-- 1 oracle dba 45692955 Jul 21 11:17 export3.dmp.Z
#

Why are all three files growing simultaneously? Isn't Unix scripts supposed to step through one line at a time? I expected to see only the export1.dmp.Z file created and growing, then when it is completed, the next file should be created etc. I am worried that the three export processes are actually not running correctly and that maybe the dmp files are corrupted and unusable.