Jerry: Are you sure. Please make sure that what you are saying is correct. The SSELECT statement has traditionally sorted on the @ID last for the last 30 years. It would be news to me to learn that it sorts BY @ID automatically first because of the double S in SSELECT.
Thus SSELECT FILE BY CITY should be different than SSELECT FILE BY @ID BY CITY as the first would gather all the records BY CITY then within each CITY, they would be sorted by @ID (the default). Using @ID anywhere but the last sort field (or implied) would not make sense as they are guaranteed to be unique and not need a tie breaker. Please check again. Thanks Mark Johnson ----- Original Message ----- From: "Jerry Banker" <[EMAIL PROTECTED]> To: <u2-users@listserver.u2ug.org> Sent: Thursday, August 09, 2007 9:39 AM Subject: RE: [U2] [UV] Speeding up a big BY.EXP select > The way I see it the first one will take longer than the second, > although it would have to be a large file you are selecting on. The > reason would be that the first one sorts the ID's, redundantly, twice > before it gets to the BY.EXP whereas the second one sorts by the ID only > once. > > -----Original Message----- > From: Boydell, Stuart [mailto:[EMAIL PROTECTED] > Sent: Thursday, August 09, 2007 2:27 AM > To: u2-users@listserver.u2ug.org > Subject: [U2] [UV] Speeding up a big BY.EXP select > > I have a large file with an MV set I need to do an exploding sort > against (about 2 million records, about 20 MVs per record). I'm not > actually after any particular sort order but it's taking hours. > I'm wondering if there is any efficiency advantage by telling it to use > a primary sort on the ID or just to sort on the MV attribute? > My (probably flawed) reasoning is that if the primary sort is on the id > then the sort process wouldn't have to build up one big explode - as it > would have a primary sort by record, it then only needs to explode each > record at a time. > > Eg. > SSELECT BIGFILE BY @ID BY.EXP MV.ATTRIBUTE > Or > SSELECT BIGFILE BY.EXP MV.ATTRIBUTE > > Anyone know the answer to that one? > > Stuart Boydell > > > > ********************************************************************** > This email message and any files transmitted with it are confidential > and intended solely for the use of addressed recipient(s). If you have > received this communication in error, please reply to this e-mail to > notify the sender of its incorrect delivery and then delete it and your > reply. It is your responsibility to check this email and any > attachments for viruses and defects before opening or sending them on. > Spotless collects information about you to provide and market our > services. For information about use, disclosure and access, see our > privacy policy at http://www.spotless.com.au > Please consider our environment before printing this email. > ********************************************************************** > ------- > u2-users mailing list > u2-users@listserver.u2ug.org > To unsubscribe please visit http://listserver.u2ug.org/ > ------- > u2-users mailing list > u2-users@listserver.u2ug.org > To unsubscribe please visit http://listserver.u2ug.org/ ------- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
