Hi Pawel,
Short summary from Jim:
"If this is a fairly static file then using J4/JP files with a decent
modulo and the HASHMETHOD of 2 is what you want. 3 and 4 are basically
"Pick" compatible and are not very good compared to 2.
If the file is very dynamic or needs to be bigger than 2GB, you can
now
use J5 files on jBASE 5. These do not need to be resized. However, the
performance of these files is terrible and there are all sorts of
response times issues on writes and so on. I would not use them
myself :-("
>From "jBASE Files.pdf":
"HASHMETHOD
Used when a hash file is to be created. The numeric parameter nnn
specifies the hashing method to be used when accessing the file.
The default method of 2 works very well with all sorts of key types.
However if the record keys will be perfectly uniform numeric keys
then there may be a slight advantage to using method 1 on the file.
TYPE
J3 – files with configurable levels of flushing
J4 – standard hash files (the default)
JP – jPLUS files
UD – Directory files used to access files in the OS"
Yet another useful link:
http://groups.google.pl/group/jBASE/browse_thread/thread/fc4a61d0a5777b50/f2950c5f918cb52a?hl=pl&lnk=gst&q=hash+jbase#f2950c5f918cb52a
Hope that some group member will give some more details, eg. about J3
flushing levels.
Kind regards
Pawel
On 16 Cze, 20:50, pawel <[email protected]> wrote:
> Hi All
>
> Could anybody explain me differences between diferent hash file
> format?
> I mean HASH3(j3), HASH4(j4) and JP.
>
> jsh test ~ -->jstat -v ../bnk.data/pd/FBNK.PD.B001
> File ../bnk.data/pd/FBNK.PD.B001
> Type=J3 , Hash method = 5 , Created Mon Jun 15 18:16:07 2009
> Groups = 280011 , Frame size = 1024 bytes , Secondary Record Size =
> 2048 bytes
> Restore re-size parameters : (none)
> File size = 1532420096 bytes , Inode = 5221128 , Device = Id 2949122
> Last Accessed Mon Jun 15 18:30:02 2009 , Last Modified Mon Jun 15
> 18:30:02 2009
> Backup = YES , Log = YES , Rollback = YES , Secure updates = NO
>
> Record Count = 2430591 , Record Bytes = 1321644218
> Bytes/Record = 543 , Bytes/Group = 4719
> Primary file space: Total Frames = 1238769 , Total Bytes =
> 1100816016
> Secondary file space: Total Frames = 257734 , Total Bytes =
> 220828202
>
> jsh test ~ -->jstat -v FBNK.PD.BALANCES.HIST
> File ../bnk.data/pd/FBNK.PD.B001
> Type=J3 , Hash method = 5 , Created Tue Jun 16 18:41:28 2009
> Groups = 280001 , Frame size = 4096 bytes , Secondary Record Size =
> 8192 bytes
> Restore re-size parameters : (none)
> File size = 1878487040 bytes , Inode = 4887491 , Device = Id 2949122
> Last Accessed Tue Jun 16 18:47:08 2009 , Last Modified Tue Jun 16
> 18:47:08 2009
> Backup = YES , Log = YES , Rollback = YES , Secure updates = NO
>
> Record Count = 2432713 , Record Bytes = 1322414964
> Bytes/Record = 543 , Bytes/Group = 4722
> Primary file space: Total Frames = 458547 , Total Bytes =
> 1322201998
> Secondary file space: Total Frames = 67 , Total Bytes = 212966
>
> jsh test ~ -->jstat -v ../bnk.data/pd/FBNK.PD.B001
> File ../bnk.data/pd/FBNK.PD.B001
> Type=J4 , Hash method = 3
> Created at Mon Jun 15 17:38:02 2009
> Groups = 280005 , Frame size = 4096 bytes , Secondary Record Size =
> 8192 bytes
> Restore re-size parameters : (none)
> File size = 1897713664 bytes , Inode = 5221129 , Device = Id 2949122
> Last Accessed Mon Jun 15 18:03:20 2009 , Last Modified Mon Jun 15
> 18:03:20 2009
> Backup = YES , Log = YES , Rollback = YES , Network = AUTO
>
> Record Count = 2430591 , Record Bytes = 1331151885
> Bytes/Record = 547 , Bytes/Group = 4754
> Primary file space: Total Frames = 463238 , Total Bytes =
> 1330938919
> Secondary file space: Total Frames = 70 , Total Bytes = 212966
>
> jsh test ~ -->jstat -v ../bnk.data/pd/FBNK.PD.B001
> File ../bnk.data/pd/FBNK.PD.B001
> Type=JP , Hash method = 5 , Created Tue Jun 16 18:32:33 2009
> Groups = 280005 , Frame size = 4096 bytes , Secondary Record Size =
> 8192 bytes
> Restore re-size parameters : (none)
> File size = 1881387008 bytes , Inode = 4917579 , Device = Id 2949122
> Last Accessed Tue Jun 16 18:39:51 2009 , Last Modified Tue Jun 16
> 18:39:51 2009
> Backup = YES , Log = YES , Rollback = YES , Network = NO, Secure
> updates = NO
>
> Record Count = 2432713 , Record Bytes = 1322414964
> Bytes/Record = 543 , Bytes/Group = 4722
> Primary file space: Total Frames = 459255 , Total Bytes =
> 1322201998
> Secondary file space: Total Frames = 67 , Total Bytes = 212966
>
> RELEASE Information: Major 4.1 , Minor 5.17 , Patch 5690 (Change
> 52756)
> AIX 5.3
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