4D Doc Center : Get table fragmentation

4D v13.4

Get table fragmentation


Get table fragmentation ( aTable ) -> Function result

Parameter	Type	Description
aTable	Table	Table for which to get the fragmentation rate
Function result	Real	Percentage of fragmentation

Description

The Get table fragmentation command returns the percentage of logical fragmentation for the records of the table designated by the aTable parameter.

The rate of logical fragmentation of the records indicates whether the records are stored in an ordered manner in the data file. If the fragmentation becomes too high, this can considerably slow down sorts and sequential searches on the table. A fragmentation percentage of 0 corresponds to no fragmentation. Beyond a rate of 20%, it may be useful to compact the data file.

Example

This maintenance method lets you request the compacting of the data file in the case where there is considerable fragmentation in at least one table of the database:

 ToBeCompacted:=False

 For($i ;1;Get last table number)

    If(Is table number valid($i))

       If(Get table fragmentation(Table($i)->)>20)

          ToBeCompacted:=True

       End if

    End if

 End for

 If(ToBeCompacted)

  // Places a marker requesting compacting

 End if