The Ultimate Guide to High Availability with MariaDB

How to use procmon to trace mysqld.exe filesystem access

You are viewing an old version of this article. View the current version here.

This article provides walkthrough on using Process Monitor on Windows, tracing file system access by mysqld.exe during "install plugin" call.

Download

Process Monitor is an advanced monitoring tool for Windows that shows real-time file system, Registry and process/thread activity. It is a part of sysinternals suite developed by Mark Russinovich and Bryce Cogswell. Process monitor can be directly downloaded from http://download.sysinternals.com/files/ProcessMonitor.zip . More description can be found at http:technet.microsoft.com/en-us/sysinternals/bb896645.aspx

Installation

There is no installation necessary, the single executable can be used after unpacking. I suggest to put procmon into a some directory in PATH.

Example of taking a mysqld.exe trace

The purpose of the following exersize is to learn how to use procmon to trace mysqld.exe calls to filesystem.

We assume that mysqld.exe is already started. 1. Start procmon.exe . Dialog will pop up that offers to set filter. Use this dialog to set filter to "Process name" "is" "mysqld.exe", as show in the screenshot below. Filter Setup

Click on "Add" button to mysqld.exe to include it in the filter, "Apply" and "OK".

2. Capture events (Menu File=>Capture Events (Ctrl+E)

3. Start mysql command line client and connect to the server Execute

mysql> install plugin blackhole soname 'ha_blackhole.dll';
Query OK, 0 rows affected (0.03 sec)

4. Saving the trace

Back to Process Monitor Windows, you should see the filesystem events initiated by the "INSTALL PLUGIN" operation

Process Monitor Events

To save it, Chose File/Save.

(Advanced) Seeing stack traces corresponding to events

It is also possible to see stacktraces corresponding to the events. For this to work , symbols support needs to be configured. This needs to be only done once.

1. Install Debugging Tools for Windows (google on how to do that) 2. Switch to Process Monitor's menu Options => Configure symbols. 3. Add dbghelp.dll from your installation of Debugging Tools into "dbghelp.dll path" input field . On my system it is C:\Program Files\Debugging Tools for Windows (x64)\dbghelp.dll

4. In "symbol path" input field,add srv*C:\symbols*http://msdl.microsoft.com/download/symbols;<path\to\you\installation\bin> (substitute last last path element with real path to your installation)

This is how it looks on my machine:

Symbol Config

Once symbols are configured , you'll get stack trace corresponding to filesystem events by simply doubleclicking on the line corresponding to event. This is what I see after clicking on the first event of my tracing session (corresponds to opening my.ini file)

Callstack

Comments

Comments loading...
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.