go to Start | Run.
2. Type cmd and Click OK.
3. Type in "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\BIN\stsadm.exe" -o setproperty -pn developer-dashboard -pv OnDemand

Reset IIS

After IIS Reset is completed go to your SharePoint site.  Look

Click on the icon in the top right corner and developer dashboard will be visible.

Clicking on the database queries will show us the query in detail.