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Fragmentation Factor is calculated incorrectly on large tables

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TitleFragmentation Factor is calculated incorrectly on large tables
URL Namefragmentation-factor-is-calculated-incorrectly-on-large-tables
Article Number000204067
EnvironmentProduct: OpenEdge
Version: 11.x, 12.0,12.1, 12.2, 12.3, 12.4
OS: All supported platforms
Question/Problem Description

TABANALYS Fragmentation Factor is calculated incorrectly on TB size tables / Records above 5,000,000,000
Fragmentation Factor ranges from 4.0 to 8.7 indicates that every record is fragmented into more than 2 pieces which is not the case
When records are larger than the database blocksize, they account for a small percentage of the total records yet the Fragmentation Factor is high

Steps to ReproduceRun TABANALYS on a database with TB size tables / Records above 5,000,000,000
Clarifying Information
Example: All records are less than the database blocksize ( 8KB ), all should have a fragments factor of 1.0 
                                  Record Size (B)----------Fragments--Scatter
Table           Records     Size   Min Max Mean         Count Factor   Factor

PUB.table10  17151878686    1.2T    54 132   77    17152094837    4.0      1.0 
PUB.table11   4560578248    1.2T    55 166   90    14560693639    8.7      1.0 
PUB.table12   5529457222  417.1G    63 111   81     5530256786    4.5      1.0

 
Error Message
Defect NumberOCTA-38480
Enhancement Number
Cause
The idealFragment variable used in the record fragment factor calculation overflows at ~4.3 billion (2^32) fragments, which results in the mis-calculation.
 
Resolution
Fixed version(s): OpenEdge 12.5, OpenEdge 12.2.7, OpenEdge 11.7.11
Workaround
Recalculate Approximation:  These tables should all have a Fragments Factor of 1, the records per block for the area is 128 
Table                 Records   #FRAGS RPB(MEAN)  MIN BLOCKS        SIZE (KB)  SIZE BLOCKS FRAG FACTOR
PUB.table10    17,151,878,686  216,151      106  161,217,610   1,288,490,189   161,061,274       1.00 
PUB.table11    14,560,578,248  115,391       91  159,967,290   1,288,490,189   161,061,274       1.01 
PUB.table12     1,139,248,518  799,564      101   54,673,588     437,361,050    54,670,131       1.00 



 
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Last Modified Date10/23/2023 12:08 PM
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