Investigating memory issues. Additional info.

I'll add here some additional information about memory issues from time to time.

This post is only for those who have already read first and second posts.

I often receive questions if !dumpheap shows real size of the objects. Surely not - it shows only "own" size of the objects, without counting the size of its members. But if you need to know real object size, it can be done by using !objsize command. Only remember, that you need to pass some object address to this command:


0:058> !objsize 13c00824
sizeof(13c00824) =    156261460 (   0x9505c54) bytes (Sitecore.Data.Items.Item)

Without setting a parameter, !objsize will go through all objects in managed memory and count their size. This will take a looooong time. Maybe even a couple of days.

Only note, that all these result sizes may overlap each other, just because we have singletones and (I assume) static objects. So if a lot of objects of some type have huge size, and you have a lot of such objects  - check their members, most of all they have some common member.

One more useful thing. If you want to take a look through all gcroots of objects of some type, it would be great to use Windbg loops:

.foreach (obj { !dumpheap -type System.SomeType -short }) { !gcroot ${obj} }