Hi Xze, Secondary space is not a bad thing
Secondary space is for storing ( individual ) records that exceed the Primary frame size, eg items that are larger than 4096 bytes The actual item data ( ie the individual item exceeding 4096 bytes, or 8192 bytes in the case of 'F.LOCKING' above( I assume a Seperation of 2 was used when creating the 'F.LOCKING' file ) is held in the Secondary space The Primary space used for such ( large ) items simply holds a 'pointer' to the 'out of group' data, so the 'Primary space' requirement for large items is minimal, and the actual data for the item is efficiently held 'out of group' The 'thing to compare', when deciding whether the file needs resizing, is the 'Groups' ( '250001' in the case of the 'FBNK.EB.CONTRACT.BALANCES' file ) with the current 'Primary file space: Total Frames' ( '259220' in the case of the 'FBNK.EB.CONTRACT.BALANCES' file ) If the 'Primary file space: Total Frames is in excess of the 'Groups', then the 'Primary file space' contains 'linked' frames Meaning for each update / access of an item within any of the 'Groups' , with a 'linked' frame, instead of having a maximum of '4096' bytes to scan in order to find the item within the Group, at least 2 frames of data may be scanned in order to find the required item The higher the ratio of 'Total Frames ( in Primary space)' to the 'Groups' the higher the likelihood that there are more than just one linked frame in each 'Group', eg for the 'FBNK.EB.CONTRACT.BALANCES' file above Groups : 250001 Frames in Primary Space : 259220 So there are at least 9219 linked Frames in Primary space, ie approximately 4% of the Groups in the 'FBNK.EB.CONTRACT.BALANCES' file have a 'linked' frame [ which on the whole is not too bad ], but could be improved by resizing this file with a modulo of 26501 ( say ) Pat. On 2 Mar, 09:18, "[Xze]" <[email protected]> wrote: > Dear all, > > I'm using the jstat utility to check the attributes of hashed files and for > some of them i can see data in primary space but for others in both, primary > and secondary > > My question is how to find whether a file needs resize or not based on jstat > output (for both cases) and if it needs how to calculate the new modulo > > As an example you can consider the following files: > > jsh ~ -->jstat -v F.LOCKING > File ../bnk.data/eb/F.LOCKING > Type=J4 , Hash method = 5 > Created at Wed Jan 6 19:45:35 2010 > Groups = 1629 , Frame size = 8192 bytes , Secondary Record Size = 16384 > bytes > Restore re-size parameters : (none) > File size = 16457728 bytes , Inode = 1248028 , Device = Id > 9223372212948434946 > Last Accessed Tue Mar 2 08:40:18 2010 , Last Modified Tue Mar 2 08:40:18 > 2010 > Backup = YES , Log = YES , Rollback = YES , Network = AUTO > > Record Count = 24207 , Record Bytes = 10265930 > Bytes/Record = 424 , Bytes/Group = 6301 > Primary file space: Total Frames = 1950 , Total Bytes = 9840241 > Secondary file space: Total Frames = 56 , Total Bytes = 425689 > > jsh ~ -->jstat -v FBNK.EB.CONTRACT.BALANCES > File ../bnk.data/re/FBNK_EB_CONTRACT_BALANCES > Type=J4 , Hash method = 5 > Created at Wed Feb 24 10:56:56 2010 > Groups = 250001 , Frame size = 4096 bytes , Secondary Record Size = 8192 > bytes > Restore re-size parameters : (none) > File size = 1061769216 bytes , Inode = 1230014 , Device = Id > 9223372212948434946 > Last Accessed Wed Feb 24 14:34:34 2010 , Last Modified Wed Feb 24 14:34:34 > 2010 > Backup = YES , Log = YES , Rollback = YES , Network = AUTO > > Record Count = 1346947 , Record Bytes = 387310863 > Bytes/Record = 287 , Bytes/Group = 1549 > Primary file space: Total Frames = 259220 , Total Bytes = 387310863 > Secondary file space: Total Frames = 0 , Total Bytes = 0 > > System Information > ================== > > OS AIX 5.3.9.0 > jbase: Major 5.0 , Minor 20 , Patch 0364 (Change 85159) > > Regards, > Xze -- 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
