Finished - Radar Chart Google Spreadsheet Gadget, That Is!

I believe I have finished the work on creating a Radar Chart Google Spreadsheet Gadget. Here are the changes since my previous release:

• Added the ability to toggle individual records on and off in the chart. This allows better visual comparison between different records and/or the overall average.
• Added the ability to toggle the competency line on and off. Also, if user does not input a competency value, the line would not be shown at all.
• Added better error handling when any of the user inputs, spreadsheet data is not a number.
• Added a process to determine the real maximum value for scales in radar chart.
• Fixed the alignment problems of labels with various number of radar lines (columns).
• Changed the gadget size to have a default height of 250px so it renders properly in iGoogle.
• Changed the gadget size to use dynamic height for large records set.
• Added a user configurable refresh time for the gadget, and default is 5 minutes.
  
• If "Calculate average" is chosen, then the gadget will draw the radar chart of the overall average by default. Otherwise, it will draw the radar chart of all records.
• Added a comment field.

This is what the current release looks like:

You can use this gadget with your own spreadsheet data. Here is how:

• Open your Google spreadsheet, and choose Gadget on the Insert menu (or right click on the spreadsheet and choose Insert Gadget):
• In the Add a Gadget pop-up window, choose Custom.
• Under URL of your own gadget, put int the following URL: http://hosting.gmodules.com/ig/gadgets/file/115560173853763482292/radar-chart.xml?nocache
  
• Click Add.
• Follow the instructions in the gadget interface to configure the gadget.

You can give me feedback via the comments section.

If it looks good, I will submit it to the Google Gadget Gallery in a couple of weeks.

My First Radar Chart Google Spreadsheet Gadget

The charts and gadgets in Google spreadsheet offer a number of interesting ways to help in visualizing our assessment data. Gadgets further offer a way to present the visualization information into a web page or one's iGoogle page. However, Google spreadsheet does not have a radar chart gadget by default which is an important piece in visualizing data harvested in our transformative assessment effort (currently known as the Harvesting Grade Book). For a brief background information, see my post on Using Google Chart API to Implement Harvesting Grade Book.

I started to look into ways to combine the Google Chart API, Spreadsheet API and Gadget API. While searching around, I found that Greg Schechter had made a spider web google spreadsheet gadget and it is listed in the Google Visualization API Gadget Gallery. Great!

But as it turns out, it does not provide all the functionalities we need, such as calculating the overall average, drawing a competency line, drawing the scales, adding a title to the chart and it also does not work in Internet Explorer at all. But it gives me, the first time developer of Google spreadsheet gadget, a good starting point. And I found myself busy with writing a radar chart google spreadsheet gadget these days.

The program logic is not difficult at all. But woe to the existence of Internet Explorer browser. I estimated spending 3 times more effort just to work around it's problems.

First, Internet Explorer does not support the HTML5 canvas tag for 2D command-based drawing. To bring the same functionality to it, I found the ExplorerCanvas javascript which I could include into the code.

Second, Internet Explorer (specifically the ExplorerCanvas script) does not support dynamic creation of canvas using innerHTML. To work around the problem, I need to use createElement and initElement instead.

if(navigator.appName == "Microsoft Internet Explorer")

{

var chartCanvas = document.createElement("canvas");

chartCanvas.id = "radarchart_canvas";

chartMainDiv.appendChild(chartCanvas);
chartCanvas=window.G_vmlCanvasManager.initElement(chartCanvas);

}

Third, Google gadgets run in browser quirks mode as according to Gadget Specifications. What it means to me is that the gadget renders differently in Internet Explorer. This article Quirks mode and strict mode provides more detail information. To work around the problem, I have to change the css accordingly.

Last (at least for now), Internet Explorer would not draw any arc or circle if the center is a floating point value. To fix the problem, I use parseInt to convert the floating point to integer.

This is the first beta release of my radar chart spreadsheet gadget.

If you want to test using this gadget with your own spreadsheet data, you can go to your Google spreadsheet to insert the gadget:

• In the Add a Gadget pop-up window, choose Custom.
• Under URL of your own gadget, put int the following URL:
  http://hosting.gmodules.com/ig/gadgets/file/115560173853763482292/radar-chart.xml?nocache
• Click Add.
• Follow the instructions in the gadget interface to choose your range of spreadsheet data, etc.

Next, I will work on changing the gadget to use checkbox in the selection of graphing data on the right. Then one can choose multiple data (radar area) to be displayed together. This allows easy comparison of one data set to another, or the overall average.

Please give me feedback via the comments section.

SQL Database Point-In-Time Restore of Transaction Log Backup

A Teaching Assistant (TA) deleted all the grades in an assignment in our online learning management system, eLearning (powered by Blackboard Learning System CE). What happened was a series of actions that leaded to this. Here is what was described to me (I'm yet to be able to successfully simulate it):

The TA used the grade book tool to enter the grades of all students in a particular assignment (instead of using the assignment tool). He then changed the due date of that assignment to a later date. The system gave him a warning message, but he simply went ahead to proceed. He subsequently found that all the grades he entered for that assignment were gone.

Now I had to find a way to retrieve the grades from our old backups. But the challenge was he did not remember when (approximate date and time) he entered the grades, and when he modified the assignment properties which caused all the grades to be cleared.

I parsed our web server logs (using Cygwin's gawk) looking for all his POST requests with grade book and other strings in the URL. Yes! I saw the log entires dated April 14 around midnight, with the last update at 0:56am.

Therefore, I restored our elearning database backups (onto a test instance) to the April 14 0:57am state. Here is the SQL script.

restore database webctdatabase from DISK='D:\backupfolder\webctdatabase_backup_200904120005.bak' WITH NORECOVERY, REPLACE

restore database webctdatabase from DISK='D:\backupfolder\webctdatabase_backup_200904140005.dif' WITH NORECOVERY

restore log webctdatabase from DISK='D:\backupfolder\webctdatabase_backup_200904140250.trn' WITH RECOVERY, STOPAT = 'Apr 14, 2009 00:57:00 AM'

restore database webctdatabase$PF from DISK='D:\backupfolder\webctdatabase$PF_backup_200904120005.bak' WITH NORECOVERY, REPLACE

restore database webctdatabase$PF from DISK='D:\backupfolder\webctdatabase$PF_backup_200904140005.dif' WITH NORECOVERY

restore log webctdatabase$PF from DISK='D:\backupfolder\webctdatabase$PF_backup_200904140250.trn' WITH RECOVERY, STOPAT = 'Apr 14, 2009 00:57:00 AM'

A little background info: We ran eLearning full database backup once a week (Sunday), a differential backup nightly (Monday to Saturday), and transaction log backups throughout the day. Therefore, when restoring from backup, I needed to restore the full database backup (as of April 12 Sunday), the last differential backup (as of April 14 Tuesday), and the transaction log backup to the specific point-in-time.

After the restore was completed, I also had to execute the following SQL commands to set the webct and webct$PF users' SID on the test instance properly.

Use webctdatabase

go

sp_change_users_login 'report'

Use webctdatabase

go

sp_change_users_login 'update_one', 'webct', 'webct'

Use webctdatabase

go

sp_change_users_login 'update_one', 'webct$PF', 'webct$PF'

Use webctdatabase$PF

go

sp_change_users_login 'report'

Use webctdatabase$PF

go

sp_change_users_login 'update_one', 'webct', 'webct'

Use webctdatabase$PF

go

sp_change_users_login 'update_one', 'webct$PF', 'webct$PF'

Then I restarted the webct service on the frontend node of the test instance to bring up the application. I logoned to it and could see all the student grades in that section/assignment. We exported them for the TA.

Saved by the transaction log backups.

APC UPS Monitoring using SNMP

I just finished configuring IPSentry to monitor our APC UPS (via SNMP).

Currently, IPSentry will send email alerts to us when the UPS batteries need replacing, etc. But if the main power is out and the battery run time remaining is under certain threshold, it will send us alerts to our cell phones instead. We also tested using it to call a script which automate the shutdown of our servers and it works. We may decide to implement it eventually, but I feel we need more observations to verify the reliability of the monitoring before doing so (since that script is so powerful and any false alarm can cause our entire shop to be shutdown).

Anyway, here are the OIDs we are now monitoring:

OID	Description	Date Type
.1.3.6.1.4.1.318.1.1.1.2.1.2	The elapsed time since the UPS has switched to battery power.	timeticks n mins = n*6000 timeticks
.1.3.6.1.4.1.318.1.1.1.2.2.1	The remaining battery capacity expressed in percent of full capacity.	gauge
.1.3.6.1.4.1.318.1.1.1.2.2.2	The current internal UPS temperature expressed in Celsius.	gauge
.1.3.6.1.4.1.318.1.1.1.2.2.3	The UPS battery run time remaining before battery exhaustion.	timeticks n mins = n*6000 timeticks
.1.3.6.1.4.1.318.1.1.1.2.2.4	Indicates whether the UPS batteries need replacing.	integer noBatteryNeedsReplacing (1) batteryNeedsReplacing (2)

More eLearning User Penetration Numbers

In December 2007, I wrote a script to determine the user penetration rate of eLearning, our online Learning Management System (powered by Blackboard Learning System CE6). We have subsequently upgraded the system to CE8 with all the latest service packs. Fortunately, the script continues to work.

Here are the numbers for the main Pullman campus:

Semester	Undergraduate Students			Graduate Students			Undergraduate + Graduate Students
	Total	LMS	%	Total	LMS	%	Total	LMS	%
2007 Fall	15441	12862	83.30	1981	749	37.81	17422	13611	78.13
2008 Spring	14383	12079	83.98	1874	747	39.86	16257	12826	78.90
2008 Fall	15571	14521	93.26	1998	1165	58.31	17569	15686	89.28
2009 Spring	14650	12968	88.52	1939	936	48.27	16589	13904	83.81

Using rsync on Windows

I posted an article on an issue of SQL Memory Paged Out During Large File Copy last month, which documented my effort in finding a way to solve the issue. Yes, rsync (from Cygwin) is still our final choice.

Today I'm going to post some tips on using rsync on Windows.

To install rsync, run the Cygwin setup.exe installer and install rsync package. After that, I would recommend adding Cygwin's bin folder into your environment path. This way, you can call rsync directly from the command line.

• Right click on My Computer. Choose Properties.
• Click on Advanced tab.
  
• Click on Environment Variables button. (The Environment Variables window will be opened)
  
• Under System variables, highlight Path. Click Edit.
  
• At the end of the Variable value, append ;c:\cygwin\bin (or wherever your installation path is. Don't forget the semi-colon in front).
  
• Click OK | OK | OK to finish.
  

Now you can use rsync to copy file in the command window, like the followings:

rsync.exe \\fromserver\share\filename d:\backupfolder\filename

But there is another issue. The destination file (copied via rsync) is owned by the user account running rsync. One may prefer to have the file permissions inherited from the parent folder instead. To fix that, I use the setacl utility from SourceForge.

The following commands first change the file ownership to local Administrators group of the backup server, clear the discretionary and security access control lists (DACL, SACL) of the file, and finally set the ACLs to be inherited from the parent folder.

setacl.exe -on filename -ot file -actn setowner -ownr "n:backupserver\Administrators;s:n"
setacl.exe -on filename -ot file -actn clear -clr dacl,sacl

setacl.exe -on filename -ot file -actn setprot -op "dacl:np;sacl:np"

Put them all into a batch file, and you have a simple script to perform nightly backup using rsync.

Web Slides on Harvesting Grade Book

Diigo has a feature where you can create a "List" of bookmarks. Inside the list, you can order the bookmarks in any sequence you want, and create a slide show from it.

I just created a series called The Evolution of Harvesting Grade Book. It tells the story behind some of the transformative assessment projects our department has been working on - visualized through what is currently called the "Harvesting Grade Book".