one possibility comes to mind: there is not enough room in the original directory for the uncompressed file and the compressed one (both exist while the uncompress is running)
--- Pat Howe <[EMAIL PROTECTED]> 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: Pat Howe > 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). __________________________________________________ Do You Yahoo!? HotJobs - Search Thousands of New Jobs http://www.hotjobs.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Rachel Carmichael 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).
