From: r...@lynden.com
To: u2-users@listserver.u2ug.org
Date: Tue, 3 Jul 2012 10:21:16 -0700
Subject: Re: [U2] RESIZE - dynamic files
(record + id / 4096 or 2048)
You need to factor in overhead & the split factor: (records + ids) * 1.1 * 1.25 / 4096 (for 80%)
If you use a 20% merge factor and a 80% split factor, the file will start
merging unless you delete 60 percent of your records. If you use 90% split
factor, you will have more overflowed groups. These numbers refer to the total
amount of data in the file, not to any individual group.
For records of the size that you have, I do not see any advantage to using a
larger, 4096, group size. You will end up with twice the number of records per
group vs 2048 (~ 13 vs ~ 7 ), and a little slower keyed access.
-Rick
-----Original Message-----
From: u2-users-boun...@listserver.u2ug.org
[mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Chris Austin
Sent: Tuesday, July 03, 2012 9:48 AM
To: u2-users@listserver.u2ug.org
Subject: Re: [U2] RESIZE - dynamic files
File name .................. GENACCTRN_POSTED
Pathname ................... GENACCTRN_POSTED
File type .................. DYNAMIC
File style and revision .... 32BIT Revision 12
Hashing Algorithm .......... GENERAL
No. of groups (modulus) .... 92776 current ( minimum 31, 89 empty,
28229 overflowed, 2485 badly )
Number of records .......... 1290469
Large record size .......... 3267 bytes
Number of large records .... 180
Group size ................. 4096 bytes
Load factors ............... 80% (split), 50% (merge) and 80% (actual)
Total size ................. 500600832 bytes
Total size of record data .. 287035391 bytes
Total size of record IDs ... 21508449 bytes
Unused space ............... 192048800 bytes
Total space for records .... 500592640 bytes
----
Using the record above, how would I calculate the following?
1) MINIMUM.MODULUS (Is there a formula to use or should I add 20% to the
current number)?
2) SPLIT - would 90% seem about right?
3) MERGE - would 20% seem about right?
4) Large Record Size - does 3276 seem right?
5) Group Size - should I be using 4096?
I'm just a bit confused as to how to set these, I saw the formula to calculate
the MINIMUM.MODULUS which is (record + id / 4096 or 2048) but I always get a
lower number
than my current modulus..
I also saw where it said to simply take your current modulus # and add 10-20%
and set the MINIMUM.MODULUS based on that..
Based on the table above I'm just trying to get an idea of what these should be
set at.
Thanks,
Chris
From: cjausti...@hotmail.com
To: u2-users@listserver.u2ug.org
Date: Tue, 3 Jul 2012 10:28:17 -0500
Subject: Re: [U2] RESIZE - dynamic files
Doug,
When I do the math I come up with a different # (see below):
File name .................. TEST_FILE
Pathname ................... TEST_FILE
File type .................. DYNAMIC
File style and revision .... 32BIT Revision 12
Hashing Algorithm .......... GENERAL
No. of groups (modulus) .... 82850 current ( minimum 24, 104 empty,
26225 overflowed, 1441 badly )
Number of records .......... 1157122
Large record size .......... 2036 bytes
Number of large records .... 576
Group size ................. 4096 bytes
Load factors ............... 80% (split), 50% (merge) and 80% (actual)
Total size ................. 449605632 bytes
Total size of record data .. 258687736 bytes
Total size of record IDs ... 19283300 bytes
Unused space ............... 171626404 bytes
Total space for records .... 449597440 bytes
------
258,687,736 bytes - Total size of record data
19,283,300 bytes - Total size of record IDs
===========
277,971,036 bytes (record + id's)
277,971,036 / 4,084 = 68,063 bytes (minimum modulus)
------
68,063 is less than the current modulus of 82,850. Something with this formula doesn't seem right because if I use that formula I always calculate a
minimum modulus of less than the current modulus.
Thanks,
Chris
Date: Mon, 2 Jul 2012 16:08:16 -0600
From: dave...@gmail.com
To: u2-users@listserver.u2ug.org
Subject: Re: [U2] RESIZE - dynamic files
Hi Chris:
You cannot get away with not resizing dynamic files in my experience. The
files do not split and merge like we are led to believe. The separator is
not used on dynamic files. Your Universe file is badly sized. The math
below will get you reasonably file size.
Let's do the math:
258687736 (Record Size)
192283300 (Key Size)
========
450,971,036 (Data and Key Size)
4096 (Group Size)
- 12 (32 Bit Overhead)
====
4084 Usable Space
450971036/4084 = Minimum Modulo 110424 (Prime is 110431)
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Regards,
Doug
www.u2logic.com/tools.html
"XLr8Resizer for the rest of us"
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