Vishal Shukla

When it comes to performance issues most of the time it’s the code

2010-07-18T01:41:41-05:00:00

For the past 4 weeks I have been assigned on a project with lot of performance issues. It’s an asp .net 3.5 project based on DNN 4.9 framework. The project is quite complex and the team has already put in almost 50 man years in the project and as usual most of the efforts were towards getting functional part working as per requirements.

At first I tried to verify the server configurations and other parameters to make sure that there was no issue with any of that. After couple of days of research and making sure everything looked ok, I decided to take a look at the code and the real problems started popping up, I will summarize some of the issues that we discovered during the last 2 weeks, the purpose of this blog entry is not to pin point what all was wrong in the code but some of the areas that might get neglected in many projects

Looking at the performance counters I noticed that the number of CLR exceptions where really high (300% of total requests) and the acceptable value is anything below 5%. So we started an exercise to run the project in debug mode with stop on debugger option and found out that
- one of the common module which was called on all pages was trying to set value of a property (int32) with database column that was BigInt. This small change took care of 60-70% of total exceptions. An ORM like EF would have avoided these kind of errors at development time itself.
- The Response.Redirect causes ThreadAbortExcpetion as the normal processing of page has been terminated. The same applies to Response.End and Server.Transfer To avoid this exception you have to use Response.Redirect(Page, False), but this will cause the execution to continue after the redirect statement. To avoid this use HttpContext.ApplicationInstance.CompleteRequest(). This took care of another 10% of the exceptions. For more on this issue refer to MSDN article.
- We found few more pages where the exceptions were used to determine business process flow, we replaced the logic by adding out parameter and using it to determine the flow.
- Still there are about 6% exceptions, but that’s way down from 300% of the total requests. so for now we have stopped looking further. The whole process took just 2 days from 2 developers and we were able to improve the web server health significantly.

Another counter that we noticed is the active sessions. The number of active sessions was steadily going high, ideally in load test after the test has been run for one user with logout the session should be released (aborted) for that user. And in fact the sign out code was doing that but the culprit was default page with login screen where after logout user was getting redirected. In the default page the dropdown for language was getting loaded and it was storing the default language in the session variable so that it will be available to the next page after user clicks login. So the session was getting aborted after user clicks sign out but then as soon as the default page was being processed a new session was being created, and this one would have stayed alive on the server till it times out. This issue was causing lot of unused sessions at the server and was forcing application restart after few continuous load tests.

The last area that we targeted on web side is the grid control. The application required totally configurable grid controller with customization on row level, filters, business rules and security. And using MS grid and relying on their events to perform this customization was getting expensive. So we wrote our own server grid control and put all the customizations on this grid control. This also gave us improvement of 50-60% on web side.

Finally we have reached a situation were our web server is in good health and now the whole attention is on database side as the CPU utilization on database server is going up to 100%. We have identified some queries and SPs and are working on them. There might still be some issues with the asp .net code but unless we bring the database to the level where it will perform at the same level as current web it will be difficult to find those areas. In coming post I will try to put down findings from database side.

But the key to the whole process was just monitoring some key performance indicators and doing a code review of some core modules. There is an excellent book online at MSDN on the whole process and specially Chapter 15 and chapter 17.

FL .Net Speaker Idol

2010-01-13T09:29:46-06:00:00

FL Dot Net User groups are conduction the Florida Microsoft Community Speaker Idol competition through out various dot net groups. The purpose of the Microsoft Speaker Idol competition is to enable lesser known members of the technical community to be recognized for their talents and speaking abilities. For more details on the competition please visit

Florida Microsoft Community Speaker Idol

As part of the first phase of the competition we are holding a speaker Idol competition at the Fort Lauderdale user group on Jan 19th and at West Palm user group on Jan 26th.

If you are in south Florida and want to take advantage of this opportunity please visit FL Dot Net and register.

SSWUG vConference

2009-10-19T13:30:51-05:00:00

Last week I did my session recordings for the SSWUG vConference and it was great, this time I am doing 4 sessions and I kept all of them at level 100 as I remembered when I started looking at these topics few months back I was struggling myself. There is so much information on the Internet but its hard to find introductory topics, topics which will tell you in short what the technology is all about, in what case you need it. I hope I have done a good job at that :)

BTW if anyone wants to register for the event they can use "SPVSUVC09" coupon code and that should save them $25, not bad. Plus the total cost is also very less compare to other conferences so great opportunity for all of us to save some bucks and attend the great sessions seating at home or office in comfort.

SQL Saturday – Miami

2009-08-08T13:35:23-05:00:00

Wow what an event considering that it was first SQL Saturday event in South Florida, now the next event we have to setup is where Scott Klein will jump in a pool full of alligators, (he had promised in one of the SQL PASS meetings that he would do that if we have more than 300 registered attendees, and it was way more than that).

I did a session on ADO .Net sync services (my favorite), one thing that surprises me is that it’s been out for well over 2 years and still has not found a big user base. It’s a great product; imagine the capability of making your application work in offline mode is great. But I guess it’s mainly because most of us are still busy in churning out applications that are over kill for a poor browser, we have a complicated ERP applications running on a browser; which was meant for publishing static information. Hopefully in future people will start going back to the Rich client applications when WPF, click once and WCF takes off in real sense. I developed my first smart client application in 2002 using win-forms and web services and haven’t looked back.

Below are the links for the ppt and my code project article.

Presentation

Sync in 2 Tier

Sync in Multitier

And for those of you who attended the session and had question regarding insert with duplicate primary key, I promise to come up with example on that one.

ReadyBoost feature in Windows Vista and Windows 7

2009-07-13T19:22:36-05:00:00

REadyBoost is one of the very usefull feature that was introduced in Windows Vista. Recently I asked few of my colleagues and friends about this feature and only couple of them knew about it, so thought of adding a blog post on this one.

You can increase the performance of your machine by using a high speed USB flash drive to supplement your RAM. Upgrading RAM on a machine can be expensive plus the machines have their limitations on how much can you add more. Even though it won’t be same as upgrading RAM on the machine, it can be as fast as 10 times reading from physical disk. You can go to MSDN to find out how you will configure your Vista or Window 7 to take advantage of ReadyBoost.

What I don't like about Windows OS

2009-07-08T17:44:31-05:00:00

Today the news about Google coming out with its own operating system "Chrome" is all over the Internet and I was wondering can they make an in-road into the OS field which is basically been dominated by Microsoft for decades. And the answer to that is possibly yes, if not as a full fledge OS for desktops and servers but for portable devices.

There are 2 things that I hate most about windows OS first it takes forever to boot the OS, since I had SP1 installed on my Vista it takes more than 5 minutes just to boot the machine (I have dual core CPU with 4 GB of Ram with high speed HDD), it seems that the OS has gone into some kind of comma, and it's frustrating. Windows 7 seems to be lot better but I still have to see one with all the applications and junk loaded on it. Here Google is giving indications that it wants to keep its OS simple and lighter for the faster boot up. Vista may have many features that are great and that's the reason it may be taking forever to load, but 90% of the users are not even aware of those Features, so why load them by default, let the user turn it on as they need it.

Second feature that I use to hate about windows is that currently it lacks security against spy ware and viruses which they have finally decided to take care by offering Microsoft Security Essentials. I feel that security should always have been part of OS, Windows did have Windows defender but it did not have protection against viruses and spy-wares. One could get the anti-virus with Live One care plan but not many people were aware of the plan and it was like buying a car first and then buying it's warranty plan (here we are not even talking about the extended warranty :) ). Microsoft has promised to release the Security Essentials during the second half of 2009 and one can download the Beta from Microsoft site . Reviews on CNet are mixed, will have to wait and see how the final product turns out.

>> Update: I just checked the Microsoft site and they are not accepting any more participants for the Beta testing of Security Essentials so if you have not downloaded already you may have to wait for some time.

It may take years for Google to come up with a serious OS for the desktops and laptops but for the portable devises and netbooks it may come up with a good solution.

SQL Server 2008 New Data types

2009-07-01T12:15:26-05:00:00

Yesterday I was trying to create my first database on SQL 2008 and thought let me check out if there are any new data types that I can take advantage of and yes in fact there are. The best I liked is Date and Time data type, how many times we needed a field just to store either the date part or just the time part and we ended up using DateTime data type which stores both date and time when you don't need both. Besides saving space in storage it saves the hurdle of reformatting or massaging the code while displaying, comparing or manipulating. I use Oracle more often then SQL sever (not by my choice) and each time we have to compare the date part we have to remember to do the TRUNC to remove the time part, same applies while displaying the fields on screen. Some time we just want to store the time part like Shift start and end time, we still end up storing both date and time and then remove date before displaying. It's just annoying. Also on storage side the date field just takes up 3 bytes instead of 8, one may say that in current time when we are dealing with Tera bytes of data how much does 5 bytes matter; I would say there is no alternative to responsive design.

When I designed my tables first time I added the fields with SQL 2005 in mind, good that I checked the new types and even though I had to redesign some of my tables I think it's worth the efforts :)

Check out TechNet for nice article explaining the types in detail.

That's the fun being in IT field you can never say you know the it, every time you cross check you will learn something new. Happy learning.

Virtual Earth development with silverlight

2009-06-24T08:41:39-05:00:00

Yesterday Telmo Sampaio of Blue Dasher Technologies presented Virtual Earth development with silverlight at the West Palm Beach .net user group and it was more than amazing. During his presentation he demonstrated how one can take the mapping applications to next level with the help of silverlight, now the maps on your application need not be just plain maps with zoom in and zoom out, you can plot any custom silverlight objects on the map and play with them. Enough said take a look at this cool application they have developed at Blue Dasher

http://www.bluedashertech.com/

You can learn more about SDK download and updates from Bing Maps team blog.

SSWUG virtual conference discount code

2009-02-19T21:10:19-06:00:00

Recently I received a discount code for the virtual conference by SSWUG group, the organizers call it VIP code :) I am going to present 3 sessions under the .net conference sessions and really liked the whole concept; for less than 5% cost of what one would pay at VS live or Teched one can get same quality of session at the comfort of home or office and you can pause the session or replay them when you think it’s getting way over your head to understand the accent of guys like me.

Check out the sessions at SSWUG vConference

And if you plan to register you can save $10 on registration by using SPVVSHSP09

code. They have over 140 session in 4 different tracks.

SF Code camp 2009, Links to code and presentation for ADO .net Sync Services

2009-02-07T16:46:10-06:00:00

It was another great code camp event at Miami with so many great speakers and .net enthusiasts. The only difficult thing is to choose between tracks that you want to go.

In today's session of Sync services I saw more interest than in past which is always good and fun. For a presenter there is nothing is more satisfying than having a presentation more like a group discussion.

Below are the link for presentation and code example

ADO .Net Sync Services Presentation

2 Tier Example

N Tier Example using WCF Service