Skip to main content

Managing User Perception in long running operations

Its important to manage User Perception properly and give him feedback if you are doing a long running synchronous operation. In the web world a user can get frustrated/impatient and try to do the same operation again leading to sending even more load on your server.

We recently ran into one issue like this where registration was taking a long time due to some server issue and looking into apache logs it was taking 10 sec but users were reporting it was taking 30-40 sec. Doing registration from a browser with empty cache confirmed that it was not registration but it was the confirmation page that was taking a long time and its a plain html page. It was all because the confirmation page was making 50 requests to the server to download images/js/css. The solution that clicked to me was simple, reduce the no of images, css, JS requests. The confirmation page was downloading all these images to
  1. 25 images/css/JS for rendering Header/Footer
  2. 5 images for rendering rounded corners
  3. 5-6 JS/css/images for google analytics and other stuff.
The solution was simple, we just whacked off the header and footer from confirmation page as it was not necessary and used CSS for rounded corners (Thanks to for implementing rounded corners so easy and fast). Now registration was fast and users were happy. But it was still taking 10 sec that we are still working on to reduce, but to give user some feedback that we are doing some thing heavy on click on Register button, we are adding an Ajax popup to show Registering... (where ... is an animated gif) and we will mask out the entire screen so that user cant click on any of the buttons again.

One more example of user perception is when I was looking at Tomcat access log of one of our production servers and saw the same search request 4 times within 20 secs. The server was loaded heavily and the FullText keyword search was taking long time, due to user's successive 4 clicks it sent even more load on server and sending load average to spike through the roof.

The solution is simple and even applied by Microsoft, have you ever noticed when you are copying over 1G or more data then Windows will tell you it will take 2 min to copy the files and they show a progress bar but depending on your machine configuration and other activities that is going on it can take anywhere from 2 -3 min to do the copy. A normal user wont notice this small difference as he will see that something is going on. In our case things were not easy as Microsoft so for the time being we will disable the search button on the click and reenable it when results are downloaded.


Popular posts from this blog

RabbitMQ java clients for beginners

Here is a sample of a consumer and producer example for RabbitMQ. The steps are
Download ErlangDownload Rabbit MQ ServerDownload Rabbit MQ Java client jarsCompile and run the below two class and you are done.
This sample create a Durable Exchange, Queue and a Message. You will have to start the consumer first before you start the for the first time.

For more information on AMQP, Exchanges, Queues, read this excellent tutorial
import com.rabbitmq.client.Connection; import com.rabbitmq.client.Channel; import com.rabbitmq.client.*; public class RabbitMQProducer { public static void main(String []args) throws Exception { ConnectionFactory factory = new ConnectionFactory(); factory.setUsername("guest"); factory.setPassword("guest"); factory.setVirtualHost("/"); factory.setHost(""); factory.setPort(5672); Conne…

What a rocky start to labor day weekend

Woke up by earthquake at 7:00 AM in morning and then couldn't get to sleep. I took a bath, made my tea and started checking emails and saw that after last night deployment three storage node out of 100s of nodes were running into Full GC. What was special about the 3 nodes was that each one was in a different Data centre but it was named same app02.  This got me curious I asked the node to be taken out of rotation and take a heap dump.  Yesterday night a new release has happened and I had upgraded spymemcached library version as new relic now natively supports instrumentation on it so it was a suspect. And the hunch was a bullseye, the heap dump clearly showed it taking 1.3G and full GCs were taking 6 sec but not claiming anything.

I have a quartz job in each jvm that takes a thread dump every 5 minutes and saves last 300 of them, checking few of them quickly showed a common thread among all 3 data centres. It seems there was a long running job that was trying to replicate pending…

Email slavery

It seems I have become an EmailSlave. The first half of the day is spent in just answering to emails. There are so many emails where I am copied but I need not be. There are many emails  where its a 1-2 page email and somewhere down someone says @KP please answer this.  So it seems daily my work schedule is:
Signin to newrelic and check anomalies for 15 min. Check emails related production exception report and yes there are a ton of these report daily. Need a better tool here as this model is not scalable. I need to reduce the incoming data at me to only see relevant data like what newrelic does. May be I need to create a webapp out of these emails.Check emails for next few minutes before team callsDo team callsThen again back to checking emails until a I have taken a best shot at answering everyone waiting for my reply.Attend team meetings on Tue/Thu
Being an architect and coder at heart I don't feel satisfied at end of the day if there is nothing tangible getting done at the end.…