PowerView and System Health Session–CPU health

Over the past few months, I spent a lot of time using Excel 2013 and the Power View add-in for completing various kinds of analysis on System Health Session data for SQL Server 2012. I thought it would be a good idea to create an Excel sheet with a template which would allow me to do these activities at the click of a button. I had recently written a post on how to retrieve Report Server execution statistics using Power Pivot and Power View. I will use the same philosophy to generate the CPU usage statistics using the System Health Session.

Now, you may ask why not query the data directly into an Excel sheet. The reason I do not do this is because it allows me to add calculated fields. Additionally, it allows me to write a query to fetch the data from the System Health Session that runs on SQL Server 2012 and above instances.

I had written an article on SSWUG on how to parse the scheduler_monitor_system_health_ring_buffer_recorded data and retrieve the CPU usage statistics using a SSRS report. This time around I fetched the data into a PowerPivot table. Then I added a new column for retrieving the day of the month using the DAY function. I also created a new calculated column for tracking the CPU usage of other processes using the SQL process utilization and system idle values. The new column is named “CPU usage (other processes)”.

Now that the PowerPivot table is ready, I used the created table as the source for a PowerView sheet in Excel 2013.

I created clustered column chart to track the following information:

  • Max CPU utilization for the SQL Server instance
  • Max CPU usage of all other processes
  • Average CPU utilization for the SQL Server instance
  • Average CPU usage of all other processes
  • Minimum CPU utilization for the SQL Server instance
  • Minimum CPU usage of all other processes

The clustered column chart uses the calculated Day field to make the chart more reader friendly. The second chart in the sheet is a line graph which tracks the average CPU usage for the SQL Server instance and other processes across a timeline. The slider at the bottom of the chart allows you to zoom in and out interactively of a time window that you are interested in.

Here is a screenshot of the final output as shown in screenshot 1. The Excel file with this visualization is available on SkyDrive at http://sdrv.ms/10O0udO

CPU usage statistics

Stay tuned to TroubleshootingSQL.com for more such visualizations!


Report Server Analytics with PowerPivot

I recently needed to query report execution statistics for a SQL Server Reporting Services instance where the number of rows were quite large. So I decided to use Excel 2013 and PowerPivot to analyze the data. This would allow me to directly pull all of the data into an Excel sheet and then perform analysis on the extracted data without having to query the Report Server database repeatedly.

The first thing to do is to create a connection to your Report Server database table. That can be done using the PowerPivot tab in Excel 2013. Click on the Manage button (Screenshot 1).


Once you are PowerPivot window, you will need to establish a connection with your Report Server database. This can be done using the From Database drop-down list with the From SQL Server option (Screenshot 2).


Create a connection to your SQL Server instance which hosts the Report Server database using the Table Import Wizard. In the Choose How to Import Data screen, select the second option i.e. Write a query that will specify the data to import. Once you click Next, provide a friendly name for the query and copy-paste the query shown below.

WHEN 0 THEN 'Interactive'
WHEN 1 THEN 'Subscription'
WHEN 2 THEN 'Refresh Cache'
ELSE 'Unknown'
END AS RequestType,
a.Format, a.InstanceName,
WHEN 1 THEN 'Render'
WHEN 2 THEN 'BookmarkNavigation'
WHEN 3 THEN 'DocumentMapNavigation'
WHEN 4 THEN 'DrillThrough'
WHEN 5 THEN 'FindString'
WHEN 6 THEN 'GetDocumentMap'
WHEN 7 THEN 'Toggle'
WHEN 8 THEN 'Sort'
WHEN 9 THEN 'Execute'
WHEN 10 THEN 'RenderEdit'
ELSE 'Unknown'
END AS ItemAction,
from dbo.ExecutionLogStorage a
inner join dbo.[Catalog] b
on a.ReportID = b.ItemID 

Now data obtained from the query will be imported into the PowerPivot table. Now I create a new PowerView sheet in the Excel workbook. Add a new column to add the TimeDataRetrieval, TimeProcessing and TimeRendering columns so that the total report duration is available at a single glance.

Now save the PowerPivot data and add a new PowerView Excel sheet called “Execution Stats”. This would allow you to create a view as shown in Screenshot 3.


Leverage PowerView’s interactive capabilities to view the Report execution statistics, the report processed status (failure or success) and the processing, rendering and data retrieval times for each report.

I have uploaded the file to SkyDrive which would allow you to connect to your own Reporting Services database and use the same report format for analysis. Stay tuned for additional PowerView sheets to give you various slicing and dicing options on report execution statistics.

Excel File Download Link: http://sdrv.ms/17ZmbK0 (Filename: SSRS_Exec_Stats.xlsx) Works with Excel 2013 only.

The case of the corrupt images

I was recently working on an environment where there was a need to find find out corrupted image streams in a database in the form of BLOBs. You might say why not run a CHECKDB on the entire table and find out if there are any inconsistencies. Well if it were that simple, I probably wouldn’t have started penning this post! 🙂 Let me give you a bit of history here to set things in perspective…. The binary stream was inconsistent when the data was inserted into the database. So this was a clear case of “Garbage In Garbage Out”.

imageWhat made the problem take a convoluted turn was the use of this BLOB data in SQL Server Reporting Services reports. If you have reports which convert BLOB data into images before rendering them into reports, then the rendering would fail if the binary stream is inconsistent. When you have a few images in the table, it’s quite possible to manually identify the inconsistent BLOB data. Now when the number of images stored in the database moves to tens of millions, I am sure the DBA will find it very amusing to spend a years looking through the images manually! So what really shows up as the image when you have a corrupted binary stream in a SSRS report is just a Red “x”! (see left).

Since the manual option didn’t seem very palatable, I thought it might be time for some automation. And that is where C# came to my rescue. The logic was very simple. Pick an image of the database, store it on the filesystem in JPG/PNG/BMP format and then verify it’s validity. There are three ways that the image being rendered can have an issue:

1. There is no image in the BLOB column in the database i.e. the column value is NULL. This is quite easy to circumvent by using the IS NOT NULL filter or the ISNULL function.
2. The image column value is not null but it stores a 0KB image which will again create a problem during the report rendering phase. This still ain’t that bad a problem as we can search for images with binary data values as 0x00 or 0x0 with relative ease!
3. The third type of image is the main problem where there might be a few bit flips or part of the binary stream is inconsistent. This makes it exceptionally difficult to locate beforehand which images will fail to render while generating the report.



If you look at the binary streams above, the last three fall under categories described above. All the image streams in read will create a problem. The first and last streams look valid but the fourth stream is invalid even though if it has a valid header.

Using the code below, you could identify the three different failure scenarios by scanning all the images that are stored as BLOBs in your database. Though if you have the need to undertake this task, then it is advisable that you perform such a validity check during off business hours.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Drawing;
using System.Data;
using System.Data.SqlClient;

namespace ImageCheck

class Program
static void Main(string[] args)
// While loop to iterate through the database table
int ctr = 1;
while (ctr <= 24)

// Wait for user input before exiting

public static void ReValidateImage(int SNo)

bool vImgCheck;
// SQL query to fetch the image
string sql = "SELECT SNo,[Document] from dbo.myTable WHERE SNo = " + SNo.ToString();

SqlConnection con = new SqlConnection("Server=.;Integrated Security=True;database=ReportDB");
SqlDataAdapter da = new SqlDataAdapter(sql, con);
SqlCommandBuilder MyCB = new SqlCommandBuilder(da);
DataSet ds = new DataSet("MyImages");
byte[] MyData = new byte[0];

// Fetch the image into a dataset
da.Fill(ds, "MyImages");
DataRow myRow;

myRow = ds.Tables["MyImages"].Rows[0];

// Store the image on the filesystem
if (myRow["document"] != null)
MyData = (byte[])myRow["document"];
int ArraySize = new int();
ArraySize = MyData.GetUpperBound(0);
// Handle ZERO kb image size
if (ArraySize > 0)
FileStream fs = new FileStream(@"C:\1.jpg", FileMode.OpenOrCreate, FileAccess.Write);
fs.Write(MyData, 0, ArraySize);
// Check image saved on filesystem for validity
using (FileStream fsRead = new FileStream(@"C:\1.jpg", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
using (StreamReader sr = new StreamReader(fsRead))
vImgCheck = IsValidImage(fsRead);
if (vImgCheck == true)
Console.WriteLine("Image is OK for iteration " + SNo.ToString());
Console.WriteLine("Image is corrupt for iteration " + SNo.ToString());
// Report ZERO kb images
Console.WriteLine("Image size is ZERO for iteration " + SNo.ToString());
catch (SystemException ex)
// Handle NULLs extracted from the database
if (ex.GetType().ToString() == "System.InvalidCastException")
Console.WriteLine("Cannot export image for iteration " + SNo.ToString());
// Function to check validity of an image
public static bool IsValidImage(Stream stream)
// Try and check if the seek is possible. If it fails, then we have problems!
stream.Position = 0;
stream.Seek(0, SeekOrigin.Begin);
catch { }
using (Image img = Image.FromStream(stream))
// IF there are no errors, then report success
return true;
return false;


A sample output of the above code when executed against a table which has two columns SNo (int) and Document (image) with SNo being the primary key would look like this:

Image is OK for iteration 1
Image size is ZERO for iteration 2
Cannot export image for iteration 3
Image is corrupt for iteration 4
Image is corrupt for iteration 5
Image is corrupt for iteration 6

So what can you do with the above code1? Firstly, you would need to modify the functions to align with the schema of your table. The second TO-DO item would be to write another function for storing the inconsistent binary stream row details in a text file or into a database table. You could even add an user interface if you want to go all out fancy!