>From the 'jstat', this file has 45,883 frames that are 'full', requiring a 'linked' frame :
Total Frames = 175074 Total Frames - original modulo 175074 - 129191 = 45,883 linked frames So the jBASE 4.1.4.19 'recommendation' of '132087' is too small, even for the existing records in this file Even with a perfect spread of items within the 132087 groups, giving 21 items per group, each 4096 byte frame has a header of 52 bytes and each item has a header of 16 bytes, leaving 3708 bytes in each frame for the 'data' [ this calculation also ( naively ) assumes that every item is of identical length ] So for the 484,741,937 bytes of data currently in this file, with a perfect spread of identically sized items, this will require a minimum of 130729 frames Unfortunately, unless your item ids are purely numeric and range sequentially from 1 thru 2761824, then Hash Method 3 will NOT give a perfect spread of items throughout these groups So the jBASE 5.0 recommendation is a more realistic value for resizing this file If the item ids are the usual combination of Alphanumeric characters, then Hash method 5 will give a more even spread of items throughout the groups, without any empty buckets, unless the modulo exceeds the number of records within the file The correction to the simplistic and original jrf has been available in all jBASE Releases since November 2006 [ jBASE 4.1.4.19 was released in February 2006 ] Pat. On 11 May, 16:59, Christophe <[email protected]> wrote: > Hi All, > > We are experiencing huge JRF modulo differences between JBase 5.0.13 > and JBase 4.4.19. See below the result of the JRF -RV on the > FBNK.RE.CONSOL.PROFIT file run in both version of JBase... Which one > is right ? We haven't experienced any performance problem with the > output provided by 4.4.19 (T25 R05). We are in the process of > upgrading to r08 with JBase 5.0.13 and a bit concerned about the new > modulo to use. 3 times bigger! > > Regards, > > Christophe > > >>>>>>>>>>>>>>>> Output from jBASE 5.0.13 <<<<<<<<<<<<<<<<<< > > jsh t6mpg ~ -->jrf -Rv FBNK.RE.CONSOL.PROFIT > FBNK.RE.CONSOL.PROFIT (../bnk.data/re/FBNK.RE.C003) Type J4, > 2761940 records at size 175, Resize from modulo 129191 to 453949. > ------------------------------------------------------------------------------- > > jsh t6mpg ~ -->COUNT FBNK.RE.CONSOL.PROFIT > 2761940 Records counted > > jsh t6mpg ~ -->jstat -v FBNK.RE.CONSOL.PROFIT > File ../bnk.data/re/FBNK.RE.C003 > Type=J4 , Hash method = 3 > Created at Sat Jan 10 22:14:06 2009 > Groups = 129191 , Frame size = 4096 bytes , Secondary Record Size = 8192 bytes > Restore re-size parameters : (none) > File size = 717107200 bytes , Inode = 55002364 , Device = Id > 9223372234423271426 > Last Accessed Fri Apr 3 16:49:53 2009 , Last Modified Fri Apr 3 16:49:53 > 2009 > Backup = YES , Log = YES , Rollback = YES , Network = AUTO > Record Count = 2761940 , Record Bytes = 484745401 > Bytes/Record = 175 , Bytes/Group = 3752 > Primary file space: Total Frames = 175074 , Total Bytes = 484745401 > Secondary file space: Total Frames = 0 , Total Bytes = 0 > > >>>>>>>>>>>>>>> output from jBASE 4.4.19 <<<<<<<<<<<<<<<<<<<<<< > > jsh t7mpg ~ -->jrf -Rv FBNK.RE.CONSOL.PROFIT > FBNK.RE.CONSOL.PROFIT (../bnk.data/re/FBNK.RE.C003) Type J4, > 2761824 records at size 175, Resize from modulo 129191 to 132087. > ------------------------------------------------------------------------------- > > jsh t7mpg ~ -->COUNT FBNK.RE.CONSOL.PROFIT > 2761824 Records counted > > jsh t7mpg ~ -->jstat -v FBNK.RE.CONSOL.PROFIT > File ../bnk.data/re/FBNK.RE.C003 > Type=J4 , Hash method = 3 > Created at Sat Jan 10 22:14:06 2009 > Groups = 129191 , Frame size = 4096 bytes , Secondary Record Size = 8192 > bytes > Restore re-size parameters : (none) > File size = 717119488 bytes , Inode = 55120837 , Device = Id 3014658 > Last Accessed Mon Apr 6 14:11:18 2009 , Last Modified Mon Apr 6 14:11:18 > 2009 > Backup = YES , Log = YES , Rollback = YES , Network = AUTO > Record Count = 2761824 , Record Bytes = 484741937 > Bytes/Record = 175 , Bytes/Group = 3752 > Primary file space: Total Frames = 175077 , Total Bytes = 484741937 > Secondary file space: Total Frames = 0 , Total Bytes = 0 --~--~---------~--~----~------------~-------~--~----~ Please read the posting guidelines at: http://groups.google.com/group/jBASE/web/Posting%20Guidelines IMPORTANT: Type T24: at the start of the subject line for questions specific to Globus/T24 To post, send email to [email protected] To unsubscribe, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jBASE?hl=en -~----------~----~----~----~------~----~------~--~---
