round function not consistent

[ramy19]

hi all,

am running into an inconsistency with simple round function depending on the decimal placing, 
 here's wat am getting 

index=_internal type=usage
| eval totalGB = b/(1024*1024*1024)
| eval roundGB= round (totalGB,5)

one day value = 4.47213

when its

eval roundGB= round (totalGB,3)    -- i get 2.791 

| eval roundGB= round (totalGB,2) -- i get 0.32

for the same day.

any idea what is happening here?

[bowesmana · Accepted solution]

If that is your search, then you are simply calculating the usage value in GB for each event you see - you are not calculating a total or doing any kind of aggregation on that data. When you say 'in the same day' you are not calculating a total for the day.

Are you really looking for something like this?

index=_internal type=usage
| bin _time span=1d
| stats sum(b) as b by _time
| eval totalGB = b/(1024*1024*1024)
| eval roundGB= round (totalGB,5)

which aggregates the total of the bytes value (b) and then calculates total in GB, by day? Or done in a different way using timechart

index=_internal type=usage
| timechart span=1d sum(b) as b 
| eval totalGB = b/(1024*1024*1024)
| eval roundGB= round (totalGB,5)

[ramy19]

thx a lot @bowesmana 
yes actually that's what am after, i didn't mention part in my question (don't know y), but yea, that helps a lot.

my mistake is that i was rounding in gigs before the sum, and since the original values of b are in bytes so rounding the gig value with 2 decimal places was zero for almost all of the events.

lesson learned, no rounding before sum (especially with smaller values)

[venkatasri]

@ramy19 Shouldn't be such big different for rounding 2,3 and 5. As you see they are consistent. It all depends on how your totalGB looks like that might be varying between rounding 2,3 and 5.

See how is your totalGB looks like as below,

---

Hope this reply helps!