[U2] UV HASH.HELP error
Sorry I forgot the subject line the first time. I've also tested this on our Linux system running the same revision with the same results. Jerry -Original Message- From: Jerry Banker [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 20, 2007 8:58 AM To: u2-users@listserver.u2ug.org Subject: I just came across what may be a bug in HASH.HELP. I ran HASH.HELP on a static hash file and it told me the smallest modulus should be 80015 (yes, not a prime number), smallest separation or 4, and the best type of 10. I then ran HASH.HELP.DETAIL on the same file and got 80021, 4, and 18 respectively. In this second case the modulus is a prime number. No changes were being made on the system because it is our test system and I was the only one on it at the time. This was on Solaris 8 running Universe 10.1.12 in Reality flavor. --- 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/
RE: [U2] UV HASH.HELP error
Actually, this could be a VERY OLD feature ... :-) I seem to remember it being documented that HASH.HELP and HASH.HELP.DETAIL (or similar) had a habit of disagreeing with each other on Prime INFORMATION. Now that's going back some ... ! Anyway, the advice always was don't trust HASH.HELP. Suck it and see Cheers, Wol -Original Message- From: Jerry Banker [mailto:[EMAIL PROTECTED] Sent: 20 June 2007 15:12 To: u2-users@listserver.u2ug.org Subject: [U2] UV HASH.HELP error Sorry I forgot the subject line the first time. I've also tested this on our Linux system running the same revision with the same results. Jerry -Original Message- From: Jerry Banker [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 20, 2007 8:58 AM To: u2-users@listserver.u2ug.org Subject: I just came across what may be a bug in HASH.HELP. I ran HASH.HELP on a static hash file and it told me the smallest modulus should be 80015 (yes, not a prime number), smallest separation or 4, and the best type of 10. I then ran HASH.HELP.DETAIL on the same file and got 80021, 4, and 18 respectively. In this second case the modulus is a prime number. No changes were being made on the system because it is our test system and I was the only one on it at the time. This was on Solaris 8 running Universe 10.1.12 in Reality flavor. --- 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/
RE: [U2] UV HASH.HELP error
HASH.HELP has improved over the years, but I sure wouldn't accept its results blindly! The most interesting part of your post, to me, is the variation in type recommendations -- type 10 v.s. 18. As you suggest, the modulo should be made a prime whether it's calculated by HASH.HELP or some other source. For the type, the basic problem with HASH.HELP is that it uses only an analysis of the record key patterns. This is inferior to a simulation approach. Of the available Universe tools I'd choose HASH.AID, testing all the types 2 through 18, and then looking at the resultant data (LIST HASH.AID.FILE) for smallest overflow and tightest hashing. HASH.AID isn't perfect as it doesn't report empty groups but at least it is a simulation rather than just eyeballing the record keys. Of course, the main thing is to keep those files sized! An implemented non-optimum resize is better than a theoretical perfect solution. Jeff Fitzgerald Fitzgerald Long, Inc. www.fitzlong.com -Original Message- From: Jerry Banker [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 20, 2007 8:58 AM To: u2-users@listserver.u2ug.org Subject: I just came across what may be a bug in HASH.HELP. I ran HASH.HELP on a static hash file and it told me the smallest modulus should be 80015 (yes, not a prime number), smallest separation or 4, and the best type of 10. I then ran HASH.HELP.DETAIL on the same file and got 80021, 4, and 18 respectively. In this second case the modulus is a prime number. No changes were being made on the system because it is our test system and I was the only one on it at the time. This was on Solaris 8 running Universe 10.1.12 in Reality flavor. --- 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/