Microsoft's LiveSearch cashback program

Ooohhh...is this the Google killer? Are they going to grab market share from Google? Apparently some of the analysts think so. Hahaha is all I can say. I won't be surprised if people search on Google for cash back and then go to the Microsoft's cashback site to take advantage of the offer. Thats still secondary. Here's the kicker....

I picked the very first thing I saw on Live Search - a Canon PowerShot A470 - gray and with Cash back, the lowest offer $107.31.

I did a Google Product search for the same thing - Cheapest Price - $97.99 from Amazon!

Here's the thing, you can offer people all the candy they want, but once the candy runs out, they're not going to stay for a second longer. It's like the politicians and their promises, it only lasts till election day.

So, for Microsoft to "disrupt" the model, I sure hope they come up with a better search engine, not better candy. Otherwise, all they're going to do is spend their money and get nothing for it in return.

Ohh - and by the way - from what I see on Microsoft's site, when the vendor charges you more, you get a bigger cash back (ofcourse, it's not enough to beat the lower price by any margin).

I think I'm going to stick to Google. I'm waiting for Google to announce it's next quarter results. It would be really nice to see Google announcing better returns and more searches, and Microsoft announcing ....well....!

Tools to Evaluate Web Design

I've spoken about how much I like coradiant, especially with the way they can capture all of the Web users session data etc.

On a different note, while thats good to evaluate the response time of pages etc, what about how much users actually like the webpage, or what they're doing on a webpage. I came across this posting from sixrevisions : 7 Incredibly Useful Tools for Evaluating a Web Design. Sixrevisions is going to be come a daily stop for me now!

I already use YSlow and it's pretty neat, especially when you want to track down whats taking the most time, or how best to optimize your webpage, but there are a few more tools that caught my eye.

Also, incase you miss it, there is a note about
Crazy Egg from one of the commenters on sixrevisons :

ncdeveloper

April 22nd, 2008

Crazy Egg is NOT for a production website by any means. I use it for the EPA websites and while it looks nice and flashy, it is not accurate at all after a few weeks. The counts just seem to go loopy after a few weeks. Support is just as weak. Every time I called, it sounded as if I woke the guy up or pulled him away from a tv show. Obviously a small company that was unprepared for moderate to high volume. If you have clients that want a real and accurate heatmap, look elswhere.


Please note, that that comment is there only because I'vnt tried it yet, but its also a fairly significant comment. I'm sure the reader(s) of this blog will understand that I'm in no way for or against using any of the tools on that site. I've tried only YSlow and I highly recommend it though :)

MySQL applications

Well, I've been using MySQL for the past few months now, and I guess, this list is again a good list to keep handy i.e. Handy Applications for a mysql database.

http://sixrevisions.com/tools/applications_mysql_databases/

Some really cool Web Developer tools

Ok....this got "Dugg" and is on my list. I've tried some of the tools provided on these pages, but some of the tools (FireBug & Web Developer for Firefox) are just amazing.

Here's a list of the Top 20 Useful tools for Web Development.
http://sixrevisions.com/tools/20_web_development_tools/

And if you do use IE (ughh)
http://sixrevisions.com/tools/internet_explorer_extensions_addons_web_developers/

Apparently - one of my colleagues who used the Microsoft Web Developer toolbar long time ago had tremendous trouble with it. He doesn't know how it is now.

Anyways - now there's more to look at.

SQL Statements - Always evaluate on the right side of the expression

While trying to tune a SQL Stored procedure, the DBA came across this statement....

select X from where id * -1 = id

That would mean that the optimizer doesn't know what index to use and that simple query took almost 1/2 second with 1000's of reads.

All he did was switch that around
select X from where id = id * -1

It executed in 0 seconds.

The entire stored procedure shed more than 1/2 the time it took to return data!

His simple statement: Always evaluate on the Right Hand Side!

Truesight TCP Timeout

So, this past week when looking at the TrueSight data from Coradiant, something jumped out at me. Though the data was being returned on the screen (from the Web app), truesight was reporting it as a Timeout (Server time out). This was odd.

I put in a call to the friendly Coradiant tech support. In 2 mins, the support tech got to the bottom of it. It turns out that TrueSight's TCP timeout was set to 30 seconds. Well, with our Ajax call, it just didn't work. Getting that time out set to 300 seconds (yes, horrible performance -- I know, we are working on that too) took care of it.

This information on how to make this change is not public, and must be done only by a Truesight tech. So, while its not something that we can change, it's something that the new Truesight image will atleast allow us to change!

Netezza

This is just a quick post....

A colleague of mine was talking about how he was working with Netezza on a project of his, and I thought I'd look it up. It seems to be a super fast Data warehousing database. It's actually a DW Appliance!!!!

They move the analytics right next to the database, and things what you would need to do by pulling out data are instead being done right on the Db. Wow!

Something to check out I guess - and see if it will make sense to your app.


Here's a picture from their website:

Etags - Performance slowdowns / network bandwidth waste

A friend and ex-colleague of mine (Anand) introduced me today to the Firefox plugin YSlow.

I quickly installed it on Firefox since I already had Firebug installed. This is an awesome plugin!

I ran it on our internal website, and found a number of things, but what caught my eye was Etags. I never knew what they were and wanted to dig into it a little more.

So what are Etags?
From Yahoo:

Entity tags (ETags) are a mechanism that web servers and browsers use to determine whether the component in the browser's cache matches the one on the origin server. (An "entity" is another word a "component": images, scripts, stylesheets, etc.) ETags were added to provide a mechanism for validating entities that is more flexible than the last-modified date. An ETag is a string that uniquely identifies a specific version of a component. The only format constraints are that the string be quoted. The origin server specifies the component's ETag using the ETag response header.

Heres the entire article: Etags

Yahoo further goes on to talk about what the problem is with Etags.

The problem with ETags is that they typically are constructed using attributes that make them unique to a specific server hosting a site. ETags won't match when a browser gets the original component from one server and later tries to validate that component on a different server, a situation that is all too common on Web sites that use a cluster of servers to handle requests.

Apparently, the problem exists with both Apache, IIS 5.0 & 6.0 servers. What does this mean to Load Balanced servers? It means that if the request switches from one webserver to another for any reason, then your cached image is now reloaded completely, instead of just sending a quick 304 - waste of bandwidth and perhaps worser performance (Basically by using an Etag on load balanced servers, your proxy caching and content caching don't work as well as intended!).

By removing the Etag completely (especially in LB scenarios), it can instead just validate with the Last-Modified header and not use the Etag.

I'm reiterating here, what's already said very eloquently. Be sure to read the article. They have code for fixing both Apache & IIS (link to Microsoft's article)

Keeping tests short & Data Managable: An Example

A few days ago I wrote up a blog post with some essential points to remember while performance testing. Here's why I wrote it and why I think it's a valid approach.

We had to test a very complicated application, which had many facets, it had a Web component, database component, lots of windows applications, com objects and so and so forth.

I first asked: What is it we want to find out from this test?
The response: Given what we do, and our major transactions how will our application be affected by migrating from Db version X to Db Version X+1.

That was it, simple concise objective.

What did I (we) do?
Background: All our transactions start from the Web Layer i.e the browser.

I used Coradiant to find out the most traversed paths and listed the top 50 use cases. From there, I spoke to the project manager to get a sense of what are the most critical use cases. For this particular test, all I cared were most critical. We came up with 5 (not including ofcourse the Login component)

Next: Develop the scripts and test them in house. We then took this highly portable script (I used VTS in Loadrunner to give me unique users and such) to the Testing Center.

What did we setup: The boxes were all setup by the DBA and Sys admin.
The scripts were so simple, that it took a very short time after the boxes were setup, to kick off the tests (mind you, even the scenario was created at the test center) (around or less than 1/2 hr). This is what I mean by keeping the tests, simple and reusable.

How did we test?
We first tested on Db Version X. We got X number of transactions and looked at critical response times.

Next we tested on Db Version X+1. We got a significantly lesser number of transactions and a much larger response time for a few transactions. We were immediately able to tell the vendor that there is something missing. By keeping the test length small as well as the number of transactions we were able to give this data back immediately. That means right after we validated that our test was not bogus (by resetting all the variables and running the test again) we were able to tell our Db vendor that there is a problem. In less than 2 hrs we were able to do this (2 hrs after we started running tests on the new Db version) from start to finish.

This was because we were able to see our data really quickly. I stress on this a lot, it's important to look at your data soon after the test. The most important part of your test is the data. If you get overwhelmed with it, you're doing your entire team a disservice.

How did we solve it? We got the vendor to give us a patch which was expected in the following service pack. It immediately got out transaction count up and we were off to the races.

This is a simple validation test. There a lot more complicated things in performance testing. The reason I show this as an example is because I believe that when people performance test, we try to get a lot of data, and that is good, if thats what you're looking for, but if you want to validate a build or something like this, getting overwhelmed with data is not a good thing.

Caveat: If you're doing full scale Db X to Db Y then you need to have a much more comprehensive test. Also, if you're going to look for memory leaks in your application or any other kind of leak, you're probably going to need a long running test (may be an hr or even more) to see it. (I should mention here, that my colleague actually reminded me of memory leaks and the use of long running tests after my previous post, and I thought it would be good to note it here)

Coradiant - How I use it

In my previous post Performance Testing I spoke about using Coradiant to figure out what to performance test. I must note here that Coradiant is only good for HTTP / HTTPS applications (basically webapps, for other apps, you can't use this tool)

So, what do I use Coradiant for?

1. Keep an eye on the application as a whole.
2. Figure out why, how and where a User is having trouble. (Especially when they call help and it gets escalated, this is just an awesome way to figure out where the trouble is - is it the network or the server)
3. Figure out what to put in my Loadrunner tests.
4. Help the sys admins by creating some really useful watch points to let us know what the error pages are. We found that our application was so clean (in terms of 404s), the only offending link was a missing css.
5. See if users having trouble are having trouble because of application issues or network issues, so that the correct people are notified.
6. Proactively find where pages are taking too long and let people know.
7. Use their Truesight & TruesightBI product to generate some Before and After fix graphs to validate any particular fix that has been moved into production.

Performance Testing...

Well, I've left my old job being a Performance Engineer, and into a new job with some Perf Eng responsibilities. I've used Loadrunner to do my performance testing and some of the terminology may be unique to Loadrunner.

Well, this got me reflecting, and thinking how best to implement a process here so that we are able to performance test well and rapidly implement the whole process from scratch.

Here's what I came up with.
0. Figure out WHY you are testing: Response time? Capacity Planning? Figure out WHAT you want to report (Current Performance?, Performance after changes?, Available headroom on hardware?) Now you can plan....

1. First off, identify what you want to test: Sure you know that you want to test your critical use cases, but what about after that? Sit down with some users and figure out what they use the most. Or you can use a really cool tool like Coradiant to do what you need. Using a tool like Coradiant will give you the most accessed pages, and you can get user sessions to see the most used paths. Guessing will get you only so far, but if you want to regularly test your application so that your users are always happy - tools like Coradiant are a very handy.

Test anything new thats going to be added to the application. Most Web applications are always in a constant state of development, and anything new you add, should also be tested, lest you end up with a bunch of very unhappy users.

2. Keep your tests small and repeatable: Testing 100 things at the same time will overload you with data and nothing more. You also will perhaps end up producing conditions that will never occur. That doesn't mean you should test every use case individually (which in my opinion may give you some data, but will probably never catch race conditions, deadlocks etc), it means keep a core number of tests.

When you add something new to the mix, be prepared for changes in numbers. If you are looking for exact same numbers, then you should be doing the exact same tests.

3. Length of Tests: Depending upon the application, you need to define the length of your tests. Too long tests mean that you'll have to wait a long time for results. Really short tests don't give you any reasonable data, because the users have not yet reached a stable state. I used to do 1 hr tests, but now I think that was over kill. 10 Min ramp up (100 VUsers) and 15 min tests would have given us just about the same amount of information as an hr long test.

4. Don't over complicate your testing: Remember your audience. Remember, that you want to prove / test that / whether the application will perform well under load. There are 2 different types of load:
1. Large data set
2. Large number of users on the system.

For regular testing, you need to find some sort of mid point and test. If you have written your performance tests right, you should be able to simulate 2 very easily. For 1, you will have to rely on your developers to provide an adequate data set.

Most important of all, always remember, you need to be providing useful information back to the team. Doing the same test 20 different ways will not give you useful results. Unless you define what & why you're testing, you're perhaps wasting your time.

Spring with ACEGI

There are a number of posts out there that do Spring with ACEGI.
I found this an interesting and useful tutorial when trying to hookup the Password encoder with acegi

http://www.i-proving.ca/space/Technologies/Acegi+Security+System+for+Spring

Firefox Addons for a Performance Engineer

In my life as a performance engineer, I used a few Firefox addons. They're useful in "thin slicing" as my old boss would call it.

1. Firebug
2. Web Developer
3. Live HTTP Headers (I've not used this, but am told is good)
4. Load Time Analyzer.

Spring java.lang.ClassCastException: java.lang.Long

In the error Log, you'll notice it occurs in toLoggableString within the Hibernate code


When you notice that, change your logger settings to INFO from DEBUG. It seems to go away.

This seems to be a bug with Spring / Hibernate.

Originally Where I got this answer from

Spring Hibernate tips

I've started coding in Spring - Hibernate now. I've come across many hurdles, interesting nonetheless.

Here's what I learnt today.

To get hibernate to "actually" perform the update / create on the database
use:

hibernate.hbm2ddl.auto">create
The hibernate suffix is essential.

If that doesn't work this may
http://forum.springframework.org/showthread.php?t=15009



classpath:hibernate.cfg.xml
true

As I grow to become a Performance Engineer ....Essential points to remember

1. Always instrument whats happening.
2. Make a baseline. For eg: if a process is failing at 100 users, start from 10, and create a baseline. See where the user load and memory load change dramatically. That will give you an idea of where to start looking.
3. Know the code. The code is your friend. Logging helps.
4. Don't assume that what the developers think is the probelm is the real cause of the problem. Make your own tests and verifications. More often that not, big words like "Memory Leak" etc may be used, but that may not be the real cause of the problem.

Here are some useful steps
1. Recreate the problem.
2. Create your baseline.
3. Create logging information.
4. Try to find the "breaking point" for the code.
5. Make sure you're looking at the real problem and not a referred problem. Drill down the code. Understand it well. It will help!
6. Memory problems can well be traced using Jprobe or Xloggc in java.

Connection Pooling with Java....

Remember to close the Statement, PrepareStatement & ResultSet before returning the connection back to the connection pool.

Otherwise, you'll more than likely get "Open cursors exceeded" and that connection will be useless. Even if you return it to the pool, more than likely those will not be closed.