Try the HASH.HELP command (and related commands) --B
-----Original Message----- From: owner-u2-us...@listserver.u2ug.org [mailto:owner-u2-us...@listserver.u2ug.org] On Behalf Of Andrew Nicholls Sent: Thursday, May 28, 2009 6:17 PM To: u2-users@listserver.u2ug.org Subject: [U2] Resize of large dynamic file Hi All I am trying to resize a large dynamic Unidata file for a customer but am struggling to determine the best modulo/seperation figures to use. I was under the impression that I should try and minimise the amount of overflow files but my latest attempt just seems to have made the file worse. The records are historical going back a number of years and vary widely in size. Because we have had issues in the past with trying to resize large files our standard practice now is to create a new file including indexes with the new modulo/separation and copy all the records into it. The original file had 26,521,431 records and was 62 GB in size with this file structure 25/2/33 (dat/idx/overflow). The new file was created with a modulo/separator of 1300021/4 and having copied roughly 1/2 the data I now have a file with 15,442,816 records, 28 GB and 5/1/22 (dat/idx/overflow). The formula I used to get the new figures was Records per Block = (file block size - pointer array) / (Average record length + Standard deviation from average + Average key length + 9) modulo = Total number of records / records per block I have paused the copy for now because I would like to know whether I should start again or just continue. Any thoughts/assistance would be appreciated. The GUIDE.STATS.LIS from the new file is below Regards Andrew Basic statistics: File type............................... Dynamic Hashing File size [dat001].............................. 1073737728 ... [dat005].............................. 1029955584 [over001]............................. 1073737728 ... [over022]............................. 861589504 File modulo............................. 1300021 File minimum modulo..................... 1300021 File split factor....................... 60 File merge factor....................... 40 File hash type.......................... 0 File block size......................... 4096 Free blocks in overflow file(s)......... 13 Group count: Number of level 1 overflow groups....... 5715317 Primary groups in level 1 overflow...... 1298667 Record count: Total number of records................. 15442816 Average number of records per group..... 11.88 Standard deviation from average......... 3.55 Record length: Average record length................... 55.46 Standard deviation from average......... 1511.47 Key length: Average key length...................... 13.88 Standard deviation from average......... 0.76 Data size: Average data size....................... 79.34 Standard deviation from average......... 1533.38 Total data size......................... 1225203127 ------- 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/
