SQL Server – Windows Debugger ( Windbg) – mdmp file – 2018-June ( Session 1 )

Background

SQL Server is generating mdmp files.

Let us see if the mdmp file has any thing useful in it.

Windbg

Download

My workstation is Windows 10 and so I can download the latest Windows Debugger from here.

download_WindowsSDK_20180626_1125AM

File Information

download_WindowsSDK_20180626_0946AM.png

Extract

Using 7-Zip extracted the ISO file ( 17134.12.180419-0858.rs4_release_svc_prod2_WindowsSDK.iso )

Extracted files

Here is what our files look like once extracted.

WinSDKSetup_20180628_1133AM

Windows Software Developer Kit

Pre-Installer

Rather than install directly, let us stage the files.

This will ensure that we can use them on a machine that does not have Internet access.

Outline

  1. Specify Location
  2. Windows Kit Privacy
  3. Select the features you want to download
    • Features
      • Debugging tools for Windows
  4. Download is complete

 

Image

Specify Location
Specify Location – Original

SpecifyLocation_20180626_0951AM.png

Specify Location – Revised

SpecifyLocation_20180626_0952AM.png

Windows Kits Privacy
Windows Kits Privacy – Original

WindowsKitPrivacy_20180626_0952AM.png

Select features you want to download
Select features you want to download – Original

SelectFeaturesToDownload_20180626_0953AM.png

Select features you want to download – Revised

SelectFeaturesToDownload_20180626_0954AM.png

Download Is Complete

DownloadIsComplete_20180626_0955AM.png

x86 and x64 Debugger and Tools

Folder – Installers

Please access the extract\Installers folder.

installDebugger_20180626_0957AM.png

Install

Install your OS bitness binary.

For us X64 Debuggers And Tools-x64_en-us.msi

Usage

Initiate Windbg

Initiate Windbg though :

  1. Accessing start menu
    • Windows Kits \ Windbg ( x64 )
  2. Running windbg.exe

Open Crash Dump

Open Crash dump file via the menu option “File \ Open Crash dump…”

OpenCrashDump_20180626_0102PM.png

Analysis – Initial

Once the mdmp is selected and loaded, the debugger performs an un-prompted quick analysis.

Image

analysis_04_20180626_0105PM.png

Image


Microsoft (R) Windows Debugger Version 10.0.17134.12 AMD64
Copyright (c) Microsoft Corporation. All rights reserved.

Loading Dump File [C:\SQLDump\LAB\Prod\mdmp\SQLDump0004.mdmp]
User Mini Dump File with Full Memory: Only application data is available

Comment: 'Stack Trace'
Comment: 'Non-yielding Resource Monitor'
Symbol search path is: srv*
Executable search path is:
Windows 8 Version 9200 MP (8 procs) Free x64
Product: Server, suite: TerminalServer SingleUserTS
Machine Name:
Debug session time: Fri May  4 23:13:16.000 2018 (UTC - 7:00)
System Uptime: 48 days 1:10:57.645
Process Uptime: 48 days 1:01:52.000
................................................................
................................................................
.........
Loading unloaded module list
................................................................
This dump file has an exception of interest stored in it.
The stored exception information can be accessed via .ecxr.
(660.750): Unknown exception - code 00000000 (first/second chance not available)
ntdll!NtWaitForSingleObject+0xa:
00007ffd`005f079a c3   

Explanation

  1. Comment
    • Non-yielding Resource Monitor
  2. Time Occured
    • Debug session time: Fri May 4 23:13:16.000 2018 (UTC – 7:00)
  3. Stored Exception
    • The stored exception information can be accessed via .ecxr.
      (660.750): Unknown exception – code 00000000 (first/second chance not available)
      ntdll!NtWaitForSingleObject+0xa:

Summary

We are able to tell that an mdmp file was generated due to a resource contention.

The illuminating indicator is ntdll!NtWaitForSingleObject.

In follow up posts, we will dig deeper to see which resources are pinpointed.

 

One thought on “SQL Server – Windows Debugger ( Windbg) – mdmp file – 2018-June ( Session 1 )

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s