Memory leak? Private Bytes/Virtual Bytes

[Ronald]

Hi!

As I ran in to errors like "Ran out of memory" and "Out of memory" I
supposed my website might have memoryleaks. To trace a potential memory leak
I isolated the IIS process and monitored the 'Virtual Bytes' and 'Private
Bytes' for a while.

I noticed the private bytes stays 'low' all the time. Sometimes a bit up,
sometimes a bit down. Virtual bytes also follows the same pattern for most
times. But, sometimes it increases to almost 2gb en stays there.

I've been reading for memory leaks an aggressive caching and stuff and was
wondering when there is a memory leak. In short: what does it mean thet the
amount of virtual bytes stays high? Is this probably due to caching or....?

regards,

Ronald

 

[Pat [MSFT]]

What you are describing is memory fragmentation; it is commonly caused by
small memory leaks. What OS are you running?

 

[Ronald]

Windows 2000 Advanced Server with latest updates.

I noticed the problem occurs at 'some' point at once. For days de virtual
bytes remains below 100mb and then suddenly it hits 2gb. So it seems this is
not caused by a 'small' memory leak.

What (except redim in loops) cause memoryfragmentation?

regards,

Ronald

 

[Pat [MSFT]]

From your description below, you probably have a loop that results in a
large amount of allocated memory (i.e. one heap gets extended to eat up the
rest of the VM), and then a different heap (IIS/DLLHost may have 30+ heaps)
needs to extend but can't so even though you aren't technically fragmented,
you are out of VM space so the extension fails.

Pat