I think I found the cause of a huge memory leak I was having in one of my apps.
I was rendering graphs from some data I had and was using code like what is found below:
For i As Integer = 0 to Min(Width/BAR_WIDTH,Data.Ubound)
...
End For
I was having quite a horrible memory leak in my webapp (4+gb in less than a few days) and tracked it down to 10’s of 1000’s of empty Double() arrays each with 2-3 references. I had no idea where these were coming from as nowhere in the app do I create empty Double() arrays. When I get the count once first and store it in a variable then use that to loop through, there is no leak. I just wanted to not loop past the data if it were to change while rendering. This also appears to be happing for Max as well.
Dim n As Integer = Min(Width/BAR_WIDTH,Data.Ubound)
For i As Integer = 0 to n
...
End For
Has anyone found that they are having this issue or know of a bug report for it? If not, I will post a bug report.
Interesting, not sure then, a simple project with it happening would be useful, maybe pop a ticket in with the project attached as you mentioned above, I certainly can’t think what could be causing it at this hour of the morning
I’d want to see actual code for this
I’m sure there’ lots of code that uses loops doubles and min max and I dont see anyone else reporting this as an issue
new desktop app
add push button to the window
in ots action event put
System.DebugLog Str(Runtime.MemoryUsed)
For i As Integer = 1 To 1000
Untitled(1,0,2,2)
Next
System.DebugLog Str(Runtime.MemoryUsed)
add a method
Private Sub Untitled(ParamArray data as double)
// Dim width As Double
// Const bar_width = 123
//
// For i As Integer = 0 To Min(Width/BAR_WIDTH,Data.Ubound)
//
// Next
End Sub
run a few times and push the button
seems to have nothing to do with min max etc just a paramarray
fun find
that would explain why this is not seen in other code I’m familiar with
it doesnt use paramarrays
lest you think “Oh no problem I’ll ditch the paramarray and use one I allocated”
swap the button code for this
System.DebugLog Str(Runtime.MemoryUsed)
Dim d() As Double = Array(1.0,0.0,2.0,2.0)
For i As Integer = 1 To 1000
Untitled(d)
Next
System.DebugLog Str(Runtime.MemoryUsed)
the ENDING loop condition is evaluated EVERY TIME through the loop
so with min(100,100) it evaluates min(100,100) each time which creates a new object
the first doesnt because N is computed ONCE
use the first form and you’re fine
you can see it if instead of MIN you do this in pushbutton1
[code]
Dim n As Integer = foo(100,100)
for i as integer = 0 to n
next
CountDoubles[/code]
and this in pushbutton2
For i As Integer = 0 To foo(100,100)
next
CountDoubles
and defined foo as
Public Function foo(d1 as double, d2 as double) as double
System.debuglog currentmethodname
return min(d1,d2)
End Function
FWIW this is expected and has been long standing behaviour
Dont expect it to be changed
