We used it to migrate databases... For example.. We would export, compress and send it to a pipe via RSH on a different box... thin that pipe would be used as std input into an import process. The data never hit disk except into the new database.
greg -----Original Message----- Sent: Wednesday, August 14, 2002 9:29 PM To: Multiple recipients of list ORACLE-L I know why i did it in the past, 32 bit os, 2G limitation of single file. i could run an export, compress on the fly and have a uncompressed file that is > 2G. hence you need to work it backwards, since if its > 2G, the uncompress will choke(or truncate). amazingly, that is NOT a stupid idea. joe Pat Howe wrote: >I am trying to work thru the one of the scripts that I inherited and I was >wondering if someone could shed some light on why the author used a UNIX >PIPE to uncompress a file. > >Code : >mknod /tmp/testdb_data_01.dbf_pipe p > >uncompress < /tmp/testdb_data_01.dbf_pipe > >/u06/oracle/oradata/testdb/tbs/data_01.dbf & >sleep 1 > >cp data_01.dbf.Z /tmp/testdb_data_01.dbf_pipe & > >Background : >File 'data_01.dbf.Z' exists in compress format. >We are currently in the directory where this file resides. > >My Confused Analysis : >line 1 : creates a pipe file called 'testdb_data_01.dbf_pipe' in the '/tmp' >directory >line 2 : In the background we start to uncompress from the 'PIPE file' >(FIFO) into my destination directory >'/u06/oracle/oradata/testdb/tbs/data_01.dbf' >line 3 : Puts the script to sleep for 1 second (no idea why) >line 4 : In the background it copies the compressed file (data_01.dbf.Z) to >the PIPE > >Therefore as the copy occurs (line4) - the PIPE (using a First-In-First-Out) >starts to uncompress my file (line2). > >Question : >What does this gain me ? Ie ; Why would the author do this ? >Seems to me to be alot of additional IO copying the file to '/tmp'. >Why not just uncompress the file directly to its destination directory >(/u06/oracle/oradata/testdb/tbs/) ? > >Thanks in advance > >_________________________ > Patrick J. Howe > Oracle DBA > VeriSign, Inc. > 4501 Intelco Loop SE > Olympia, WA 98507 > Phone : 360.493.6284 > Email : [EMAIL PROTECTED] > > > > -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Testa INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Loughmiller, Greg INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
