Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>To me it is the difference between being a "developer/programmer" and a "craftsman". Anyone can learn to write code and see how things just "magically happen" for you not knowing why/how. To really be valuable at what you do, I think there is a great importance to find out as much as you can about the Framework you're using. Remember it's not just a <em>language</em>, it's a Framework that you leverage to create the best application to your abilities.</p> <p>I've analyzed many memory dumps over the years and found it extremely helpful knowing the internals and differences between the two. Most of these have been OutOfMemory conditions and unstable applications. This knowledge is absolutely necessary to use WinDbg when looking at dumps. When investigating a memory dump, knowing how memory is allocated between the kernel/user-mode process and the CLR can at least tell you where to begin your analysis. </p> <p>For example, let's take an OOM case: The allocated memory you see in the Heap Sizes, Working Set, Private Memory, Shared Memory, Virtual Memory, Committed Memory, Handles, and Threads can be a big indicator of where to start.</p> <p>There about 8 different heaps that the CLR uses:</p> <ol> <li>Loader Heap: contains CLR structures and the type system </li> <li>High Frequency Heap: statics, MethodTables, FieldDescs, interface map </li> <li>Low Frequency Heap: EEClass, ClassLoader and lookup tables </li> <li>Stub Heap: stubs for CAS, COM wrappers, P/Invoke </li> <li>Large Object Heap: memory allocations that require more than 85k bytes </li> <li>GC Heap: user allocated heap memory private to the app</li> <li>JIT Code Heap: memory allocated by mscoreee (Execution Engine) and the JIT compiler for managed code</li> <li>Process/Base Heap: interop/unmanaged allocations, native memory, etc</li> </ol> <p>Finding what heap has high allocations can tell me if I have memory fragmentation, managed memory leaks, interop/unmanaged leaks, etc.</p> <p>Knowing that you have 1MB (on x86)/ 4MB (on x64) of stack space allocated for each thread that your app uses reminds me that if I have 100 threads you will have an additional 100MB of virtual memory usage.</p> <p>I had a client that had Citrix servers crashing with OutOfMemory problems, being unstable, slow responsiveness when their app was running on it in multiple sessions. After looking at the dump (I didn't have access to the server), I saw that there were over 700 threads being used by that instance of the app! Knowing the thread stack allocation, allowed me to correlate the OOMs were caused by the high thread usage. </p> <p>In short, because of what I do for my "role", it is invaluable knowledge to have. Of course even if you're not debugging memory dumps it never hurts either!</p>
    singulars
    1. This table or related slice is empty.
    1. POStack vs. Heap in .NET
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USDave Black
    1. USDave Black
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POStack vs. Heap in .NET
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload